Links (Nov 2021)


  1. Lithium theory of obesity epidemic (general overview, more on lithium grease, brine spills, bioaccumulation, well measurement data and city-level data).
  1. Dietary fat may contribute to lipostat ratcheting (leptin resistance).
  1. During the pandemic, childhood obesity has accelerated. Food purchases in the US are also spiking
  1. Death rates increase 10% during the winter. Is it because of the cold (weakened cardiovascular system), or the season (e.g., influenza doesn’t seem affected by temperature)? 
  1. What’s causing the sex recession? New data suggests a change in religious norms.


  1. Intramuscular injections can accidentally hit a vein, causing injection into the bloodstream. This could explain some of the rare adverse reactions to Covid-19 vaccine. Study shows solid link between intravenous mRNA vaccine and myocarditis (in mice). Needle aspiration is one way to prevent this from happening.
  1. Paxlovid, a bespoke protease inhibitor from Pfizer shows 89% protection from hospitalization. It may be possible to combine with molnupiravir, the new 50% protective transcriptase inhibitor from Merck.
  1. After you exclude the fraudulent and statistically illegitimate studies, several meta-analyses still show that Ivermectin can provide a small amount of protection. The effect is small compared to Paxlovid 89% or mRNA vaccines 95%, but non-zero. What’s going on? The strongyloid hypothesis.

Energy & Climate

  1. High-temperature superconductors are accelerating fusion R&D. The MIT startup is forecasting an energy-positive proof of concept as soon as 2025. 
  1. Vox: geothermal energy is poised for a big breakout. One issue with renewables (solar, wind, etc) is they have a low capacity factor: until large-scale energy storage becomes economical they need to be supplemented by high capacity energy sources. Nuclear and geothermal might qualify; main blockers are regulation and R&D, respectively. 
  1. What is France’s secret? Nuclear power.
  1. Interesting, bullish take on SpaceX. Its starship program will likely reduce the transport cost-per-kilogram by two orders of magnitude. 

Basic Science

  1. Inspired by recent neutrino results, a new dark sector theory attempts to jointly explain dark matter, Hubble tension, baryon asymmetry, and cosmic thinness.
  1. Leading candidate axion theory (explanans: CP parity, dark matter) finds preliminary support
  1. The 3D organization of our genome.
  1. The brain senses and controls immune function, as shown by optogenetic manipulations in the insula.
  1. Lead exposure accounts for a loss of 23 million IQ points in a 6-year birth cohort of US children. See also, the lead crime hypothesis.  See also, Did lead poisoning lead to the downfall of Roman Empire? The 2021 Infrastructure Investment and Jobs Act does allocate $15b for lead abatement.

Current Events

  1. China appears to be expanding its nuclear silos from 20 to 250. And increasing its stockpile to 1000 warheads by the end of the decade. And developing maneuverable hypersonic missiles that can evade US missile defense systems (analysis here). 
  2. An interesting tweetstorm investigates the port backlog and discovers anti-stacking regulations as a key bottleneck. The Port of Long Beach rescinds the rule within one day. 


  1. Another 500 ancient Maya and Olmec complexes were discovered by Lidar in southern Mexico. 
  1. Why did the War on Terror happen? One theory points to powerful bureaucrats (“Vulcans”) gaining too much control over interagency dialogue. 
  1. A geographical way of visualizing class differences
  1. In a poll of economists, opportunity cost was found to be the most underrated. Worth applying its lessons to your everyday life!
  1. Biohacking, Level 100:


Links (Oct 2021)


1. Merck claims its COVID-19 treatment molnupiravir cuts risk of hospitalizations and death in half

2. Leaked grant proposal details high-risk coronavirus research.

Obesity Epidemic

3. The future of weight loss – new drug semaglutide shows comparable efficacy to bariatric surgery.

4. The contaminant theory of the obesity epidemic.

5. The torpor (seed oil) theory of the obesity epidemic


6. Better air quality is the easiest way not to die

7. Air filtration dramatically improves hospital outcomes.

8. Syphilis likely originated in Ohio around 0 BCE, and was ultimately brought back to Europe.


9. Can we attribute our problems to a monocausal event in 1970

10. Did social media enable the rise of Trump?

11. Decline in GOP support for childhood vaccine mandates.

12. Update on Havana Syndrome: it is probably caused by “directed, pulsed microwaves”. 


13. Ancient footprints (22.5 kya) in New Mexico comprise more evidence against Clovis-first settlement theory.

14. Dairying played a major role in the rise of the Yamnaya.

15. Was Henrich wrong about his Marriage and Family Program theory of WEIRD psychology?


16. Proof assistants makes the jump to big league math.

17. More on AlphaFold.

For decades, people have considered computational error to be the most likely source of error when a predicted structure and an experimental one don’t match, and quite rightly so. But now, if you have a big mismatch between the two, it is frankly more likely to be an experimental error, because the folding predictions are getting so solid. This is disorienting, to say the least.

Existential Risks

18. The Hanson Grabby Aliens model

19. Remnants from Theia (the collision that created the moon) forever interred in the deep Earth. Tree-like plumes emanating from these LLSVPs are likely responsible for Deccan Trap volcanism and the K-Pg extinction event. 

The team estimates that, in tens of millions of years, a blob of nightmarishly gargantuan proportions will pinch off from the central cusp and rise to meet what is now South Africa’s foundations. This, said Sigloch, would produce cataclysmic eruptions. The Deccan Traps were caused by what we would think of as a solitary mantle plume. This future mega-blob, though, would be capable of producing volcanism so prolific and extensive that the Deccan Traps would be a firecracker in comparison.”

20. Mirror DNA has been successfully engineered.

“If mirror cells acquired the ability to photosynthesize, we’d be screwed. “I suspect that all hell would break loose,” says Jim Kasting, a climate scientist at Penn State University and an expert on the global carbon cycle. All it would take would be a droplet of mirror cyanobacteria squirted into the ocean. After doing some rough calculations on the effects of a mirror cyanobacteria invasion, Jim Kasting isn’t sure which would kill us first—the global famine or the ice age.


21. Like us, non-human primates also choke under pressure

22. The Appalachian mountain chain also extends into Europe. This is possible because plate tectonics separated this mountain range. The Appalachian Mountains are older than the Atlantic Ocean.

23. How a coastline 100 million years ago influences modern election results in Alabama.

24. The evolution of homeothermy.

But why 98.6 specifically? Well, Casadevall has an answer for that too. In humans, 98.6 is the optimal tradeoff between our metabolism and protection from fungal infections. 

But recall global body temperature is declining; one explanation provided by the torpor theory of obesity (Link 5 above)

Habit as Action Chunking

Part Of: Neuroeconomics sequence
Followup To: Basal Ganglia as Action Selector, Intro to Behaviorism
Content Summary: 2600 words, 13 min read

Towards a theory of habit

Life brims with habitual behavior.

All our life is but a mass of habits—practical, emotional, and intellectual—systematically organized for our weal or woe, and bearing us irresistibly toward our destiny, whatever the latter may be.

Ninety-nine hundredths or, possibly, nine hundred and ninety-nine thousandths of our activity is purely automatic and habitual, from our rising in the morning to our lying down each night. Our dressing and undressing, our eating and drinking, our greetings and partings, our hat-raisings and giving way for ladies to precede, nay, even most of the forms of our common speech, are things of a type so fixed by repetition as almost to be classed as reflex actions.

William James

Why do we find ourselves on autopilot so frequently? What happens in our brain when we switch from reflexive to reflective thought? Is there a way to objectively tell which mode your brain is in, right now?

Our brain betray the program they employ by the errors we express.

When you flip on a light switch, your behavior could be a result of the desire for illumination coupled with the belief that a certain movement will lead to it. Sometimes, however, you just turn on the light habitually without anticipating the consequences – the very context of having arrived home in a dark room automatically triggers your reaching for the light switch. While these two cases may appear similar, they differ in the extent to which they are controlled by outcome expectancy. When the light switch is known to be broken, the habit might still persist whereas the goal-directed action might not.

Yin & Knowlton (2006)

At a conceptual level, we can differentiate three cognitive phenomena: stimulus, response, and outcome. Habitual behavior uses the environment to guide its responses (an S-R map); goal-directed behavior directly optimizes the R-O relation. Goal-directed behavior occurs immediately. Habit emerges with overtraining.

In both behavioral modes, reward is used for day-by-day learning. But only goal-directed behavior is sensitive to rapid changes in the anticipated outcome. We can operationalize this with two metrics (Balleine & Dezfouli 2019):

  1. Outcome expectancy: is behavior sensitive to changes in the environment?
  2. Reward devaluation: is it sensitive to changes in intrinsic value?

Habitual behavior exhibits both.

  • Sometimes, we flip the light switch despite knowing the causal path from the light switch to the bulb is severed.
  • Sometimes, we open the refrigerator despite being full.

When a rat becomes sated, a moderately-trained rat will immediately reduce its reward-seeking behavior (e.g., press the lever fewer times). An extensively trained rat, however, will not respond to such devaluation events – a sign it is acting out of habit. Interestingly, habit only occurs in predictable environments. In a more complicated task, habit (and its index, devaluation sensitivity) does not occur.

Adjudicated Competition Theory: Model-Based vs Model-Free

The basal ganglia is an action selector, giving exclusive motor access to the behavioral program with the strongest bid. We have already seen data connecting this structure with reinforcement learning (RL). But in the RL literature, there are two different ways to implement a learner: a tree system which builds an explicit world-model, and a cache system which ignores all that complexity, and just remembers stimulus-response pairings.

These two modeling approaches have different costs and benefits:

  • Tree Systems are very costly to compute, but learn quickly & are more responsive to changes in the environment.
  • Cache Systems are easier to maintain, but learn slowly & are less responsive.

Besides driving behavior, both models also report their own uncertainty (i.e., error bars around the reward prediction). The adjudicated competition theory of habit (Daw et al 2005) suggests that the brain implements both models, and an adjudicator gives the reins to whichever model expresses the least uncertainty.

Because cache systems are more uncertain in novel environments (stemming from their low data efficiency), tree systems tend to predominate early. But as both systems learn, cache systems eventually become more relatively confident and take over behavioral control. This shift in relative uncertainty is thought to be the reason why our brains build habits if exposed to the same environment for a couple weeks.

Overtraining manufactures habits. But only sometimes! There are several quirks with our habit-generating machinery:

  • Ratio intervals (which rewards behaviors as often as they are performed) tend to preclude habit formation. Interval training (which only provides a reward every so often) is much more habitogenic.
  • Even interval training only generates habits in relatively simple circumstances: for certain tasks involves two actions, behavior can remain goal-directed indefinitely.

Amazingly, not only could Daw et al (2005) reproduce the basic phenomena of overtraining, but their model also reproduces these quirks as well!

Which two brain systems underlie goal-oriented and habitual behaviors, respectively? For that, we turn to the basal ganglia.

Three Loops: Sensorimotor, Associative, Limbic

The striatum receives input from the entire cortex. As such, the fibers which comprise the basal ganglia are rather thick. As our tracing technologies matured, anatomists were able to inspect these tracts at higher resolutions. In the 1990s, it was discovered that this “bundle of fibers” actually comprised (at least) three parallel circuits.

These are called the Sensorimotor, Associative, and Limbic loops, based on their respective cortical afferents:

It’s important to note important differences between the rodent and human striatum.

The mesolimbic and nigrostriatal dopaminergic pathways, discussed above, directly map onto the Limbic and Sensorimotor/Associative loops, respectively:

All three circuits (direct, indirect, and hyperdirect) exist in all three loops (Nougaret et al, 2013); however, I omitted hyperdirect from the above for simplicity.

Given its participation in the Limbic Loop, the mesolimbic pathway is also sometimes referred to as the reward pathway. Its component structures, the ventral tegmental area (VTA) and nucleus accumbens (NAc), are particularly important.

There have been attempts to refine these loops into more specific circuits. Pauli et al (2016), using contrastive methods, found a different 5-network parcellation, which doesn’t overlap much with the former paper. Using resting state methods, Choi et al (2012) found five ICNs embedded within the striatum. More recently, Greene et al (2020) localized individual-specific ICNs within the cortical-basal ganglia-thalamic circuit.

For now, we will mostly confine ourselves to a discussion of three loops.

Localizing The Controllers

The associative loop appears to be the basis of the goal-directed action (GD-A) system. If you lesion any component of the system, behavior becomes exclusively habitual. For example, lesions to the posterior dorsomedial striatum (pDMS), behavior becomes insensitive to changes in both reward contingency and reward value. The same effects occurs with lesions to the SNR, and mediodorsal thalamus (MD). Finally, lesions to the basolateral amygdala (BLA) also disrupt goal-directed behavior, plausibly by altering the reward signal provided by the substantia nigra (SNr).

The sensorimotor loop appears to be the basis of the habit system. If you lesion any component of the system, behavior becomes exclusively goal-directed. For example, after lesions to the dorsolateral striatum (DLS), behavior begins to track changes in both reward contingency and reward value. The same effects occurs with lesions to the GPi, and mediodorsal thalamus (MD). Finally, lesions to the posterior central nucleus of the amygdala (pCeN) also disrupt habitual behavior, plausibly by altering the reinforcement signal provided by the substantia nigra (SNc).

These conclusions are derived from both human and rodent behavioral studies (Balleine & O’Doherty 2010). In normal circumstances, these systems interoperate seamlessly. Damage to the either system, however, causes exclusive reliance on the other system.

The infralimbic cortex (IL) plays an important role in habitual behavior. Lesions to this site prevent the formation of habit (Killcross & Coutureau 2003), and even blocks expression of already formed habits (Smith et al 2012). The IL also appears critical for the formation & retention of both Pavlovian and instrumental extinction (Barker et al 2014) But habit-related activity seems to develop first in the dorsomedial striatum and only with overtraining in the IL (Smith & Graybiel 2013). In a similar manner, the prelimbic cortex (PL) appears to play an important role in goal-directed behavior.

Action Chunks and Sequence Learning

We have defined habits with respect to outcome contingency and value. But there is a third component: the sequence learning of motor skills.

Behavior is not produced continuously. Rather, it is emitted in ~200ms atomic chunks, or behavioral syllables. Some 300 syllables have been discovered in mice (Wiltschko et al 2015).

Syllables are not emitted in random order. It often pays to use representations of multi-syllable action chunks. These chunks are, in turn, concatenated into larger sequences.

How do we know this? Chunks can be detected with response time measures: within-chunk actions occur more quickly than actions at chunk boundaries. Statistical methods also exist to detect sequence boundaries (Acuna et al 2014).

Concatenation and execution response times also respond to dissociable events. Execution latencies are preferentially impacted by changing the location of the hand relative to the body; concatenation latencies preferentially respond to transcranial magnetic stimulation (TMS) of the pre-SMA area (Abrahamse et al 2013).

Action chunks tend to emerge organically every three or four keypresses. There exists an interesting analogy here to memory chunks, for example, we remember phone numbers with three or four digit chunks. The similarity between action and memory chunks may derive from a common neurological substrate.

Neural activity in the dorsolateral striatum (DLS, part of the sensorimotor loop) exhibits an interesting task bracketing pattern: firing peaks at the beginning and end of tasks. Martiros et al (2018) find that striatal projection neurons (FPNs) generate this bracketing pattern, and are complemented by fast-spiking striatal interneurons (FSIs) which fire continuously within the bracketing window.

This bracketing saves rewarding behaviors as a package for reuse. D2 antagonists don’t interfere with well-learned sequences, but does disrupt the formation of new chunks (Levesque et al 2007). Parkinson’s disease does too (Tremblay et al 2010).

Graybiel & Grafton (2015) argue that the dorsolateral striatum is specifically involved in developing skills: learning action sequences of particular value to the organism. This explains why both habitual and non-habitual skills are learned in the DLS. Indeed, innate fixed action patterns (e.g., grooming) are mediated here too (Aldridge et al 2004).

The supplementary motor area (SMA) plays a central role in implementing sequences. Rats organize their behavior with sequence learning, and lesions to the SMA disrupt these behaviors (Ostlund et al 2009). Similarly, magnetically interrupting the human SMA during a task blocks expression of the subsequent chunk (Kennerly et al 2004).

Within the SMA, the rostral pre-SMA seems to represent cognitive sequences; the caudal SMA-proper exercises motor sequences (Cona & Semenza 2016). Working memory tasks reliably activates pre-SMA, whereas language production reliably activates both pre-SMA and SMA-proper.

Hierarchy as Loop Integration

We have so far examined theories of loop competition. But consider the impact of dopamine shortages and surpluses in the various loops, per Krack et al (2010):

This data aligns with the organizational principle of hierarchy of the central nervous system. The limbic loop selects a desire, the associative loop explores its beliefs to identify a plan, and the sensorimotor loop translates those plans into motor commands. Here’s one possible interpretation, based on Guyenet (2018).

This hierarchical interpretation nicely complements results from sequence learning.

Hierarchical Collaboration Theory

We have seen computational and neurological evidence in favor of the adjudicated competition theory of habit. But the theory also has three important limitations. First, competitive models can explain devaluation behaviors, but struggles to replicate contingency responses. Second, it doesn’t explain sequence learning: why should habits coincide with the development of motor skill? Third, it doesn’t accord with hierarchy: why should habitual behaviors be concrete responses, rather than abstract actions.

This leads us to the hierarchical collaboration theory of habit. On Balleine & Dezfouli (2019)‘s model, the associative system passes command serially to the sensorimotor system. Changes in the reward environment are noticed immediately. However, as the sensorimotor system learns increasingly complex action sequences, the associative system only notices changes to the reward environment at sequence boundaries. In other words, only after a sequence is being executed will the associative system resume control. This would explain why sequence learning so strongly coincides with habit formation and reward insensitivity.

In order to model this alternative account, one must first extend RL to accommodate chunks. These chunks replace their component parts if the benefits of using that sequence exceeds its costs. This formalism is provided by Dezfouli & Balleine (2012). Dezfouli & Balleine (2013) found that their hierarchical model replicated, and in some cases outperformed, the competition model of Daw et al (2011).

The Balleine lab is not the only group to produce computational models of hierarchical collaboration. Baladron & Hamker (2020) produces an interesting model, which assigns the infralimbic (IL) cortex the role of loop shortcut between associative/goal-directed and sensorimotor/habitual systems. Their model is also interesting in that they localize the reward prediction error (RPE) to the limbic loop, while ascribing action prediction error (APE) and movement prediction error (MPE) to the associative and sensorimotor loops, respectively.

These are early days. I look forward to more granular models of habituation, with more attention to the limbic circuit. As our mechanistic models of habit formation improve, so too does our therapeutic reach. If Graybiel & Grafton (2015) is right, and addictions are simply over-strong habits, such models may someday prove useful in clinical settings.

Until next time.


  1. Abrahamse et al (2013). Control of automated behavior: insights from the discrete sequence production task
  2. Acuna et al (2014). Multi-faceted aspects of chunking enable robust algorithms.
  3. Aldridge et al (2004). Basal ganglia neural mechanisms of natural movement sequences
  4. Baladron & Hamker (2020). Habit learning in hierarchical cortex-basal ganglia loops
  5. Balleine & Dezfouli (2019). Hierarchical action control: adaptive collaboration between actions and habits
  6. Balleine & Dickinson (1998). Goal-directed instrumental action: contingency and incentive learning and their cortical substrates.
  7. Balleine & O’Doherty (2010). Human and Rodent Homologies in Action Control: Corticostriatal Determinants of Goal-Directed and Habitual Action
  8. Barker et al (2014). A unifying model of the role of the infralimbic cortex in extinction and habits
  9. Choi et al (2012). The organization of the human striatum estimated by intrinsic functional connectivity
  10. Cona & Semenza (2016). Supplementary motor area as key structure for domain-general sequence processing: a unified account
  11. Daw et al (2011). Model-based influences on humans’ choices and striatal prediction errors
  12. Dezfouli & Balleine (2012) Habits, action sequences, and reinforcement learning
  13. Dezfouli & Balleine (2013). Actions, Action Sequences and Habits: Evidence That Goal-Directed and Habitual Action Control Are Hierarchically Organized
  14. Graybiel & Grafton (2015). The striatum: where skills and habits meet
  15. Greene et al (2020). Integrative and Network Specific Connectivity of the Basal Ganglia and Thalamus Defined in Individuals.
  16. Guyenet (2018). The Hungry Brain
  17. Holland (2004). Relations between Pavlovian-i9nstrumental transfer and reinforcer devaluation.
  18. Kesby et al (2018). Dopamine, psychosis and schizophrenia: the widening gap between basic and clinical neuroscience
  19. Krack et al (2010). Deep brain stimulation: from neurology to psychiatry?
  20. Levesque et al (2007). Raclopride-induced motor consolidation impairment in primates: role of the dopamine type-2 receptor in movement chunking into integrated sequences.
  21. Martiros et al (2018). Inversely Active Striatal Projection Neurons and Interneurons Selectively Delimit Useful Behavioral Sequences
  22. Pauli et al (2016). Regional specialization within the human striatum for diverse psychological functions
  23. Killcross & Coutureau (2003). Coordination of actions and habits in the medial prefrontal cortex of rats.
  24. Smith et al (2012). Reversible online control of habitual behavior by optogenetic perturbation of medial prefrontal cortex
  25. Smith & Graybiel (2013). A dual operator view of habitual behavior reflecting cortical and striatal dynamics
  26. Tremblay et al (2010). Movement chunking during sequence learning is a dopamine-dependent processs: a study conducted in Parkinson’s disease.
  27. Wiltschko et al (2015). Mapping Sub-Second Structure in Mouse Behavior
  28. Yin et al (2005) The role of the dorsomedial striatum in instrumental conditioning 

Intro to Multilevel Societies

Part Of: Anthropogeny sequence
Content Summary: 6000 words, 30 min read

What is a Multilevel Society?

Many mammals live with others. But for the vast majority of these species, social life revolves around families, or groups – not both.

In group-living species, there are no stable breeding bonds. In such multi-male, multi-female (mm-mf) groups, mating is promiscuous. For example, Wrangham estimates that female chimpanzees copulate between 400 and 3,000 times per conception, and female bonobos between 1,800 and 12,100 times. In such species, children bond with their mother, but cannot hope to recognize their father (who could be any of the males within the group).

In family-living species, the family lives autonomously. There are two prominent kinds of primate family: pair-living families (e.g., gibbons), or in one-male units (OMUs) with one male and several females. 

But some thirteen primate species (5%) live in multifamily groups. For these species, families (polygynous OMUs) not only share the same space, but also participate in group-level relationships and behaviors.  

While some of these multifamily species exhibit two levels (family and clan), other species have more. Sometimes clans coalesce as multilevel societies  – apex levels defined first as spatial tolerance, then full-fledged social affiliation.

These concepts have been operationalized. By GPS tagging individual primates, proximity data can empirically demonstrate the existence of such levels:

Only a few species live as multi-family or multi-level societies. Here is a partial list from Grueter et al (2020):

These species come from a wide diversity of taxa, suggesting that multi-level sociality is a derived trait

Humans are one example of MLS primate. Today, we’ll dive into nonhuman primates. By understanding these species on their own terms, we should improve our ability to understand not just how mammalian societies function, but also gain insight into how our own species evolved. 

So let’s dive in! Our exemplars come from two subfamilies within the Old World Monkeys:


  • Geladas (Theropithecus gelada)
  • Hamadryas baboons (Papio hamadryas), 
  • Guinea baboons (Papio papio), discussed occasionally


  • Golden snub-nosed monkeys (Rhinopithecus roxellana). 
  • Rwenzori colobus (Colobus angolensis ruwenzorii), discussed occasionally
  • Proboscis monkeys (Nasalis larvatus), discussed occasionally

MLS Social Organization

Kappeler & van Schaik (2001) note that primate social systems rest on three pillars:

  1. social organization (typical group size, composition, spacing, and dispersal patterns of a given species)
  2. mating system (patterns of sexual behavior)
  3. social structure (patterns of relationships between individuals)

Let’s discuss social organization first.

  • Hamadryas baboons have all four layers: OMUs, clans, bands, and troops. These layers generate a multilevel allegiance system which mirrors the complexities of a human tribe. Hamadryas clans in the same band mingle while foraging, but males ally with their own clan members in a fight. Members of different clans in the same band will in turn unite against members of alien bands.
  • Geladas only have two stable layers: OMUs and bands. Rarely, when an OMU experiences binary fission, the two separated units may cooperate to form a team (Snyder-Mackler et al 2011), by virtue of the bonds of between-OMU female kinship.  Occasionally, geladas bands come together, at least spatially, into apex level communities. 
  • Golden snub-nosed monkeys have three layers. Many OMUs consistently congregate as bands. Every winter, when local food density peaks, these bands fuse into a single troop (Qi et al 2014). 

Anthropoid primates typically features unisexual dispersal: one sex disperses to preclude inbreeding, the other remains with its natal group (is philopatric). The latter typically has a kinship advantage: it maintains lifelong social ties with their same-sex relatives. 

In several MLS societies, bisexual dispersal occurs – in general, this dispersal regime tends to correspond with strong male-female bonds. Hamadryas baboons are predominantly male philopatric: most often the females disperse. Gelada baboons are female philopatric, and the males disperse. Snub-nosed monkeys are also female philopatric, and the males disperse.

Polygynous species by definition contain a sizable number of bachelor males.  Bachelors have up to three “career paths” available:

  1. Some bachelors join OMUs as followers. Leaders tolerate followers because they are often kin, and also because follower males defend against takeovers, effectively increasing OMU longevity. Followers don’t immediately receive mating access, but they do receive other benefits, detailed below.
  2. In male philopatric MLS species (e.g., hamadryas and Guinea baboons), non-follower bachelors typically become solitary
  3. In female philopatric species (e.g., geladas, snub-nosed monkeys), bachelors can choose a solitary life, but may instead join an all-male band (AMU), which poses an increased threat to OMU security.

In sum, here is how these social organizations differ (more contingent higher levels patterns are omitted for simplicity):

Novel Social Signatures

What are the cognitive demands for life in a multilevel society? For this, we begin with a primate whose cognition we understand quite well: Homo Sapiens.

Human friendships range from casual friends to more intimate associations. But the amount of time we invest in relationships is not continuously graded. Instead, ego networks naturally cluster into four separate groups: support clique (~5 people), sympathy group (~15 people), affinity group (~50 people) and affinity network (~150 people). Willingness to act altruistically tends to stop here, but the number of acquaintances people typically have is ~500, and the number of faces we can recognize may be bounded at ~1500.

These Dunbar graphs also manifest as typical sizes of human groups (Dunbar 2020); indeed, groups that don’t conform to these sizes deteriorate more quickly (Dunbar & Sosis 2018). Human groups have four nested components (family, group, clan, tribe) – is it really so surprising that we have four kinds of friends (best friends, close friends, friends, acquaintances)?

A social signature is the distribution of social effort that people invest in their friends. Individual social signatures are resistant to turnover: the distribution of our social effort doesn’t change even when we lose or add new friends (Saramaki et al 2014). But the modal social signature for multilevel primates converges on four clusters. 

What about the social signature for other primates? Kudo & Dunbar (2001) note

For the majority of the species in this sample, the mean size of networks (i.e. the number of animals linked together by a continuous chain of relationships at the defined discriminant level) is typically around 75% of total group size. This suggests that the majority of individuals are linked together in a single network, with a small number of attached peripheral individuals. These individuals either lead a solitary existence within the group or are members of very small peripheral networks.

Within these bonded networks, primates do develop unusually strong ties to a handful of conspecifics. These cliques are analogous in size and quality to best friendships we see in human beings:

This data (and the agent-based modeling of Sutcliffe et al 2016) suggests three signature archetypes across the primate order:

One benefit from the MLS acquaintance layer is plausibly information transfer. In humans this hypothesis has been explored in seminal Granovetter (1973) The Strength of Weak Ties. Henrich’s excerpt Collapse of Supermind attests to the significance of social network size to sustain cumulative culture

MLS Mating System

On to the second pillar: mating systems! 

For bachelors, there are up to four routes to reproductive success: the initial unit strategy, where a follower befriends (or solitary kidnaps) a juvenile female. The takeover strategy involves physical combat. Followers have access to two other strategies: the opportunistic strategy where you gain a harem when the leader male isn’t around, and the inheritance strategy where females are peacefully transferred from leader to follower.  To illustrate how takeovers often go, here’s Pines et al (2011) describing an April 2008 hamadryas takeover.

Takeover of ‘‘Lizzy’’ (adult female with older infant) from ‘‘Pete’’ (old leader) by ‘‘Skivy’’ (subadult solitary): Skivy was observed following Pete and his female Lizzy (Pete’s only remaining adult female). Flanked by ‘‘Herb’’ (a deposed leader with similar facial features to Pete who became Pete’s follower after his own loss of females described below) and by ‘‘Feet’’ (a young subadult follower of Pete), Pete and Lizzy were observed hastily fleeing from Skivy, who followed but did not physically interact with Pete, Herb, or Feet. Skivy continued to pursue Pete, Lizzy, and Feet the next day. On one occasion that Skivy got close to Pete and his entourage, Feet turned and chased Skivy. Approximately half an hour after this, and with Feet no longer around, Skivy approached the foraging Lizzy and grabbed her. Pete, who was about 8 m away, picked up Lizzy’s infant and fled. After a brief flurry of mounts and grooming, Skivy repeatedly herded Lizzy toward Pete and continued to mount and groom her in full view of the now deposed leader.

From a comparative perspective, hamadryas baboons have unusually enhanced levels of sexual coercion. They exhibit herding: keeping their females within 2m using e.g., neck-biting behaviors (Swedell & Schreier 2009). Male aggression peaks immediately after a takeover, and may function to condition a female. Other species have more robust expressions of female choice. Golden snub-nosed monkeys use paternity confusion to preclude takeover-driven infanticide. Guinea baboon females don’t experience “takeovers” at all; but simply move to different OMUs if their current male doesn’t suit them. 

In contrast with most mm-mf species, males in multi-level societies associate closely with females at all times. This contrasts with mm-mf primates, in which males consort and mate guard only when females are in estrus. 

MLS mating systems varies along other dimensions as well:

Intense Sexual Selection

Sexual selection can be usefully decomposed into intrasexual selection (male-male, female-female), and intersexual selection (male-female). From a male-male competition perspective, strategies vary according to social structure:

In all primates, testes size correlates with body size. However, after controlling for body size, mm-mf species have larger testes in men. This is because females have multiple copulations during estrous, and the male who delivers the most gametes has a fitness advantage (hence the arms race to produce more gametes). For example, despite being much smaller than humans, chimp testes are much larger.

In polygynous societies, where a single male forms stable breeding bonds with multiple females, males don’t have to worry about competing with other males’ sperm. But they do have to worry about bachelors challenging & overtaking their harem. And as harem sizes grow larger (bigger operational sex ratio OSR), bachelor threat becomes increasingly intense (this is polygyny’s math problem). Size and weaponry drive success in contests for sexual access. As the intensity of bachelor contests increases, we see more sexual dimorphism: males whose bodies (and teeth!) are bigger than women (Clutton-Brock et al 1977).

That’s how male-male sexual selection works in traditional primate societies. But what happens in a multilevel sociality? More specifically, what happens when you take spatially autonomous families, and have them co-reside. Two effects manifest immediately:

  1. Nearby OMU males often exacerbate opportunities for contest competition. And Grueter & van Schaik (2009) found that, indeed, sexual dimorphism is even greater in multilevel primates than traditional polygynous societies.
  2. Nearby OMU males often provide females with more opportunities for extra-pair mating (EPM). In polygynous societies, male-driven infanticide is a constant threat (killing an infant terminates lactation, and thereby accelerates oestrus). “Cheating” promotes paternity confusion, and reduces the infanticide threat. Qi et al (2020) found that, while no observed instances of EPMs occurred, paternity tests revealed more than half of all children were sired by non-resident males. 

But not just the OMU males that change the sexual selection calculus. Bachelors behave differently in multilevel societies as well!  Due to the unusually tolerant male-male dispositions required in multilevel societies, and the dramatic expansion of male kin groups outlined above, bachelor males live in unusually cooperative all-male units (AMUs). OMUs congregate together in breeding bands (BBs), AMUs congregate in all-male bands (AMBs). 

For colobus monkeys, Qi et al (2017) showed that AMBs tend to be organized along kinship lines. Their movements tend to shadow that of the breeding band. What’s more, social patterns of grooming tend to correlate with distance between these two groups – this is likely associated with preparations for violence. 

Finally, let’s consider secondary sexual traits (ornaments). These come in three varieties: hairy traits (capes, tufts, beards), fleshy traits (lips, nose, humps), and colorful traits (red hair, blue scrotum, etc). 

Such ornaments serve at least one of the following functions

  1. Status Signaling. Some ornaments signal dominance between males. 
  2. Attractiveness. Some male ornaments are associated with female choice.

In traditional social structures, individuals are well-known to one another. In multilevel societies, which occasionally coalesce into very large groups, anonymity is more prevalent. In contexts of limited social knowledge, the functional value of such ornaments is particularly high. And indeed, multilevel societies are disproportionately likely to exhibit these ornaments.

MLS Social Structure

We’ve discussed social structure and mating systems. Time for the third pillar: social structure.

In hamadryas societies, if a leader male is incapacitated, harem females will often go their own way. But in geladas, females in an OMU will stay together even if the male is deposed. This suggests that in gelada OMUs are bonded by female kin; whereas the pair-bond is the primary core unit glue in hamadryas. 

You can actually predict this pattern with social network analysis (SNA) to evaluate the social bonds of a given society. Matsuda et al (2012) found that females are more network-central to the colobines, whereas males are more central in cercopithecines. Clustering analysis, however, reveals that geladas OMUs become more unstable when females, but not males, are removed from social networks.

Why should these species differ so radically in social structure? These differences are largely driven by philopatry-based kindreds, sexual selection, and dispersal patterns. Recall that in multilevel societies, dispersal risk is lessened by transferring within the super-group. But which level do individuals transfer? Here’s some data:

Interestingly, Rwenzori colobines have a pattern of upper-level female dispersal and lower-level male dispersal. This pattern is rather unusual, and closely resembles one other MLS primate species: Homo Sapiens.

These dispersal patterns help explain social structure:

  • In hamadryas, male dispersal patterns contribute to the L2 male alliances, used to repulse bachelor males. In this species, male sexual coercion may explain the weak female bonds, even within-harem.
  • In geladas, the lack of female transfer within bands and a lack of clan-based male bonds are likely reasons why gelada bands are not maintained as coherently as hamadryas bands. 
  • In golden snub-nosed monkeys, female philopatry and the colobine penchant for allomothering generates very strong female cohesion within core units (but male-female relationships within OMUs are also quite strong). 

Primate societies typically spend their waking days together. But a minority of species (incl. chimps, bonobos and humans) operate under fission-fusion dynamics: subgroups with variable composition forage independently. Fission-fusion behavior is an adaptive response to variable foraging environments, allowing species to dynamically alter their social structure in spatiotemporally variable ecologies. The question of whether fission-fusion behavior requires additional cognitive abilities is an area of live research.

Historically, there has been a strong tendency to conflate fission-fusion with multi-level societies. But there is a key difference: in mm-mf primates that use fission-fusion dynamics, subgroups are formed on an individual basis (they are atomic communities). In contrast, multilevel, fission-fusion primates form subgroups on a familial basis (they are molecular communities). Families are never separated: they forage together. An interesting exception to this trend is human beings, which use an atomic style during the day (by the sexual division of labor, our families aren’t literally inseparable), but a molecular style at night (unlike chimps, human nature has us rather consistently sleeping with our families).

Stronger Kindreds

In comparison to mm-mf groups, the potential for kin selection-based cooperation is dramatically enhanced by multilevel social organization. Let’s dive in.

For nearly all primates, the most common philopatry pattern is female philopatry.  Only a few primate species, including our two closest relatives chimpanzees and bonobos, exhibit male philopatry. 

Primates are capable of kin recognition. We find evidence for this in nepotism (preferentially helping relatives), incest avoidance (they largely avoid mating with conspecific kin), and dominance relations (vengeance is often directed at the aggressor’s kin). Kin recognition is grounded in parental attachment, and from there an inductive ability to notice adjacent attachment relationships. But kin recognition varies by social structure. Consider the following:

Symbol Key:

  • Circle = female; Triangle = male
  • Green = fully recognized kin, Light green = imperfectly recognized kin, White = unrecognized kin
  • Red Outline = emigrant, Blue Outline = immigrant

In female philopatric mm-mf groups, (e.g., macaques) Ego recognizes her mother and children, by virtue of parturition and lactation. Ego is also able to recognize her siblings (“the other juveniles bonded to my mother”) and maternal grandmother (“the older female bonded with my mother). She may also be able to recognize her maternal aunts and uncles, and sister’s offspring, but this requires a second inferential link, and the evidence for this ability is mixed. Ego’s father does not recognize her (impossible to say who inseminated the mother), and Ego will never know her son or’s brother’s offspring (since they dispersed as juveniles).  In fact, the three males she  can recognize as kin leave. The female kin she can recognize often cooperate jockeying for dominance status. For all individuals then, matrilines (n=5) are important determinants of social structure.

In male philopatric mm-mf groups (e.g., chimps), the situation is more lonely. Resident male Ego cannot recognize his father, but he also cannot recognize his mother’s kin, because mom is an immigrant. He can recognize his siblings. But he cannot recognize his brother’s kids (even his brothers don’t know). Nor can he build alliances with his sister’s sons, because his sister emigrates. Patrilines (n=2) permeate the society, but given their shallowness, the situation is more akin to “every male for himself”. 

The situation changes when pair-bonding is introduced (the advent of multifamily groups).  

For female philopatric multifamily groups, in addition to the above, Ego gains the ability to recognize & bond with her father and maternal grandfather. These individuals may prove useful allies in her life. But these eureka moments stop their: their immigrant status prevents Ego from meeting this part of her extended family. 

For male philopatric multifamily groups (e.g., ancestral humans), we see that pair-bonding has radically improved Ego’s situation. Ego now recognizes his father, and his paternal grandfather (that older male with whom his father is most strongly bonded with). Ego can also bond with, and promote the welfare of, his children, and his (non-emigrated) extended family. He also may form weaker bonds with his brother’s offspring, and paternal uncles & aunts. The scope of patrilines radically expands, rather than a single male ally, Ego’s patriline network has achieved n=6. 

In contrast with mm-mf groups, pair-bonding dramatically expands male kin recognition. These kindreds dramatically expand the cooperative potential of agnatic kin. 

Two Evolutionary Pathways

Shultz et al (2011) model the evolution of social life within the entire primate order. The earliest primates lived solitary, nocturnal lives. The shift towards diurnal social living represents a major shift in the primate adaptive landscape, with an increased emphasis on visual processing (efficient foraging) and group living (predation mitigation).

Dunbar & Shultz (2010) argue that sociality comes in two forms. Aggregations (siimple, fluid groups) form when individuals benefit from home range overlap. Congregations (complex, bonded groups) require a repurposing of mother-offspring attachment towards others. Such animals make friends (sensu Silk 2002). Most social mammals (e.g., ungulates) live in aggregations. A few mammals (including social carnivores, dolphins, elephants, and anthropoid primates) live in congregations. 

For primates, the transition from solitary living seems to have two stages. First, there was a stage with unbonded mm-mf aggregations (eg. diurnal lemurs). This was succeeded by bonded mm-mf congregations.

As mentioned, this escape from solitary lifestyle was likely stabilized by exaptations of mother-offspring attachment. These bonds were further reinforced by a transition from bisexual dispersal to unisexual (typically male) dispersal, which enabled strong (female) kindreds. The fact that there are zero attestations of reversion back to soli, suggesting that the stabilizing role of these mechanisms.

Female philopatry is expressed in OMUs when males successfully monopolize access to females, and mm-mf when they do not. Transitions between these forms may be ecologically mediated; namely, reductions in food density that cannot support large female aggregations. This hypothesis finds support in Barton (1999)’s observation that savanna baboons, which typically form large mm-mf groups, may sometimes subdivide into polygynous groups in harsher conditions.

Shultz et al (2011) document a transition from unstable mm-mf groups to pair living and social monogamy (not to be confused with sexual monogamy).  Social monogamy evolves prior to paternal provisioning, and represents an end state. Opie et al (2013) claims that all appearances of social monogamy take place in unstable mm-mf species, all with heightened levels of infanticide risk. In contrast, Lukas & Clutton-Brock (2013) claim that all instances of pair-bonding evolved from solitary species, for the ecological reason of sparse resource → female territoriality → incentivizing male pair-living strategies. 

These two accounts have not yet been reconciled. But Kappeler (2014) suggests both pathways might be possible: lemurs show evidence of both group-living and solitary societies; moreover, the resultant monogamous systems have systematically different properties. 

What about multilevel societies? How did they evolve?

Consider again our exemplar organisms (plus lesser-known, suspected, and intermediate MLS species located in  Pygathris, Nasalis, Madrillus, and Macaca genus). Yellow denotes OMUs, red as stable MM-MFs, and blue as MLS. 

These MLS are derived from different ancestral social systems! Grueter et al (2012) outline two pathways. With the bonding pathway, pair bonding substructures ancestral mm-mf groups. But with the aggregation pathway: autonomous OMUs increasingly overlap, and ultimately affiliate. 

Comparative data may allow us to detect substages within these pathways:

First, consider the Rwenzori colobus. This species seems to be a social Archaeopteryx: it represents a transition point halfway along the bonding pathway. The African colobine group contains both OMU and mm-mf species. The Rwenzori is multilevel, but its core units can be either OMU or MM-MF. These core units often “switch modes”. For example, Stead & Teichroeb (2019) document a case where the largest mm-mf core unit, which consisted of 8 adult males and 6 adult females, split into two units: an OMU and a 7-member AMU.  It is plausible to speculate that, for the bonding pathway, a multilevel structure predates and incentivizes the ascent of OMUs. 

Second, consider the proboscis monkeys. Derived from OMU ancestors, this species appears to be halfway along the aggregation pathway: OMUs are spatially tolerant, but don’t seem socially integrated (nested OMUs). Similar results obtain for several species in the Pythagrix genus.

Third, we’ve already seen how some MLSs have an apex or fourth level (e.g., hamadryas) and some do not (e.g., geladas). This suggests that the apex level affiliation postdates multifamily groups. Let’s call this xenophilia pathway. This pathway too may decompose: from spatially tolerant behavior (nested MFS) towards direct social affiliation (true multi-level societies). 

Two Evolutionary Scenarios

What caused these certain colobines and cercopithecines to “take the leap” towards multi-level sociality?

For colobines, an important ecological determinant is diet. Snub-nosed monkeys are unusual in that their diet is dominated by lichens, a low-quality & high-abundance food. For other colobines with different dietary profiles, the amount of scramble competition is high: larger groups means more energy invested in travelling to productive forage areas. But with multilevel colobines like Rhinopithecus bieti, their diet significantly reduces scramble competition (slope is 30x smaller, in this example). 

Many other primates share this property of minimal scramble competition, yet they don’t form multilevel societies. It seems that diet is a necessary, but not sufficient precondition.

The bachelor threat hypothesis attempts to explain the snub-nosed monkey phenomenon. Consider the following facts:

  1. Higher operational sex ratios (OSRs) correlate with increasing OMU overlap (Grueter & van Shaik 2009).
  2. Multilevel species have higher OSRs  (Grueter & van Shaik 2009).
  3. Infanticide and extra-pair copulation (paternity confusion) are prevalent in these populations. 
  4. Xiang et al (2014) found that colobine males in multilevel societies often collaborate to repulse all-male bands, particularly during mating season.

Perhaps this two-pronged approach explains the evolutionary origins of geladas. Like colobines, geladas feed on low-quality, super-abundant foods (young leaves). This dietary preference dramatically reduces within-group feeding competition. However, geladas don’t suffer as much from bachelor threat. Perhaps this explains why they haven’t taken the xenophilia pathway, in contrast with colobines.

For baboons, Jolly (2020) presents a five-stage reconstruction of Papio evolutionary history, based on modern genetic data. 

  1. Originally two species (Yellow and Kinda) populated South Africa. These baboons lived in a female philopatric, mm-mf configuration. 
  2. As East Africa evergreen forest dried, a pathway opened up. A male-philopatric multi-family ancestral species (gray color, P origin point), mounted a frontier invasion (similar to how starlings colonized North America). 
  3. This multifamily species ultimately diverged into three populations (Guinea, Ancestral Northern, Hamadryas – see Fig C)
  4. Olive baboons speciate from Ancestral Northern, and revert back to female-philopatric mm-mf, separating Guinea from Hamadryas baboons.
  5. The species cross-fertilizations in the last step are visible in modern-day “discordant” mitochondrial DNA.

The invasion species P derives from Kinda baboons, which are unusual compared to other baboons for indirect male-male cooperation, as well as stronger male-female relations including comparatively intimate consortships (Petersdorf et al 2019). These features may have produced useful cognitive preadaptations for multi-level social life. 

But why would P become male philopatric? Consider a dispersing male living with a group on the frontier. If he disperses away from the (rapidly-moving) frontier, his heritage does not contribute to the subsequent generations of the expanding population. If he disperses into the frontier, he has no group to join, and his chance of starvation or predation is quite high. Finally, if he disperses along the frontier that is also disadvantageous due to the Holt-McPeek effect (Hold & McPeek 1996). Taken together we see that male dispersal is penalized, the dispersal cost-benefit tradeoff changes, and those males predisposed to remain (always a small fraction of a group) would enjoy a fitness advantage. As the frontier expands, typically by group fission seeding the horizon, this process compounds. 

Jolly (2020) suggests that this frontier-driven shift to male philopatry allowed these baboons social organization to find a new equilibrium:

Adding male philopatry to preexisting female philopatry would produce troops that were near-endogamous, reducing the effective population size and incurring the risk of inbreeding depression and/or shortage of acceptable mates. At the frontier itself, conditions would minimize this risk. Once the frontier had moved on, however, the male-philopatric troops in the fully occupied landscape behind it would no longer enjoy superabundant resources and would therefore tend to shrink toward a size sustainable as a foraging group within such a setting. Being small and endogamous, however, would imperil a troop’s survival. 

This unstable situation changes individual incentives for group encounters:

Troops formed by fusion in this way would maintain their critical size as breeding groups as long as all members frequently gathered at the sleeping site to spend social time communally. At the same time, clans/ parties could forage independently where the ecological setting favored such behavior. In this way, populations that had become male-philopatric remained viable by decoupling the socializing and co-foraging aspects of troop membership

On this hypothesis, the social dispositions of Guinea baboon makes a plausible base from which to derive hamadryas society.  In the sparser resources in the Horn of Africa, foraging units would shrink down to the “molecular” OMUs. As the sole defender of their unit, this would have put stress on the males for aggressive protection, and fewer opportunities to interact with individuals outside of their OMU, females would be more socially isolated. 

This frontier annealing hypothesis attempts to explain why some baboons embarked on the bonding pathway. But however these northern baboons did it, it’s worth noting the only known case of pathway reversion: olive baboons (Papio anubis), while ancestrally male-philopatric multi-family, reverted back to a male-dispersing mm-mf social organization. 

Roots Of Xenophilia

For many primates, xenophobia (between-group hostility) is the norm. For example, as we saw previously, coalitions of chimp males periodically raid neighboring territories, killing anyone unfortunate to cross its path. Xenophobia is largely grounded in resource competition: violence is incentivized if a neighbor possesses a valuable resource, and a group has enough physical power to capture & retain it. 

Many intergroup encounters are agonistic. But other encounters are more tolerant. What adaptive value does extra-group affiliation unlock? Examples include:

So far, I’ve described the adaptive reasons why group encounters may be hostile vs friendly. But what proximal mechanisms nudge groups in either direction? First, much empirical work has shown relatedness of extra-group members reduces aggression (because of kin selection). Second, familiarity is another key mediator, for at least three reasons:

  1. Post-fission. When a gorilla troop experiences fission, for example, it is much less likely to fight with its previous associates.  If the annealing hypothesi is correction, and large group fissions creating MLSs in Papio, this would be how they did it.
  1. Shared interest. Consider a male philopatric species, where a female leaves Group A and pair-bonds with a male in Group B. Both groups meet from time to time. Such groups have some shared kinship and built-in familiarity via the “linking individual”. Not only this, but conflict that risks harm to the link and her offspring is against the reproductive interests of both the relatives and the affines (“in-laws”). As the number of out-marriages (out-mating + pair-bonding) increase, this reason for cooperation becomes increasingly robust.
  1. Mere exposure. Even groups that don’t share many fission- or dispersal-based links may come to act cooperatively, by the brute fact that neutral exposures to strangers paves the way for affinity (in humans, this is known as the propinquity effect). 

A summary graphic of our discussion in this section:

A couple caveats are in order. First, all three affiliation promoters assume frequency of contact: if groups practice avoidance, intergroup relations are moot.  Second, the above analysis explores primarily dyadic factors. But the relationship Group B has to Group A may play a role in its receptivity to Group C. Geography plays a role. Some multilevel societies have strictly delineated & coherent apex level structures (e.g., hamadryas baboons); others are more flexible at this higher level (e.g., human beings).

Fry et al (2021) describes peace systems: certain human societies that have managed to avoid war & achieve long-term intergroup peace. And indeed, multilevel societies in other primate societies also seem less prone to intergroup aggression. It seems likely that a deeper understanding of multilevel societies might contribute to furthering the science – and practice! – of peace. 

Until next time.


Bolded references are ones I found exceptionally interesting.

  1. Arnaboldi et al (2012). Analysis of Ego Network Structure in Online Social Networks
  2. Barton (1999). Socioecology of baboons: the interaction of male and female strategies
  3. Clutton-Brock et al (1977). Sexual Dimorphism, socionomic sex ratio and body weight in primates
  4. Chapais (2008). Primeval Kinship
  5. Dixon & Vasey (2012). Beards augment perceptions of men’s age, social status, and aggressiveness, but not attractiveness 
  6. Dunbar & Shultz (2010). Bondedness and sociality
  7. Dunbar & Sosis (2018). Optimising human community sizes
  8. Dunbar (2020). Structure and function in human and primate social networks: implications for diffusion, network stability and health
  9. Fischer et al (2016). Charting the neglected West: The social system of Guinea baboons
  10. Fry et al (2020). Societies within peace systems avoid war and build positive intergroup relationships
  11. Goffe et al (2016). Social relationships of female Guinea baboons (Papio papio) in Senegal
  12. Grannovetter (1973). The strength of weak ties. 
  13. Grueter & van Schaik (2009). Sexual size dimorphism in Asian colobines revisited
  14. Grueter & van Shaik (2009). Evolutionary determinants of modular societies in colobines
  15. Grueter et al (2012). Evolution of Multilevel Social Systems in Nonhuman Primates and Humans. 
  16. Grueter et al (2015).  Are badges of status adaptive in large complex primate groups?
  17. Grueter et al (2017). Multilevel societies
  18. Grueter et al (2020). Multilevel Organisation of Animal Sociality
  19. Holt & McPeek (1996) Chaotic population dynamics favors the evolution of dispersal. 
  20. Huang et al (2017). Male Dispersal Pattern in Golden Snub-nosed Monkey (Rhinopithecus roxellana) in Qinling Mountains and its Conservation Implication
  21. Jolly et al (2020). Philopatry at the frontier: A demographically driven scenario for the evolution of multilevel societies in baboons (Papio)
  22. Kappeler & van Schaik (2001). Evolution of primate social systems
  23. Kappeler (2014). Lemur behaviour informs the evolution of social monogamy
  24. Kirkpatrick & Grueter (2010). Snub-nosed Monkeys: Multilevel Societies across varied environments
  25. Kudo & Dunbar (2001). Neocortex size and social network size in primates
  26. Layton et al (2012). Antiquity and Social Functions of Multilevel Social Organization Among Human Hunter-Gatherers
  27. Lukas & Clutton-Brock (2013) The evolution of social monogamy in mammals. 
  28. Matsuda et al (2012). Comparisons of Intraunit Relationships in Nonhuman Primates Living in Multilevel Social Systems
  29. Miller et al (2014). Diet and Use of Fallback Foods by Rwenzori Black-and-White Colobus (Colobus angolensis ruwenzori) in Rwanda: Implications for Supergroup Formation
  30. Mirville et al (2018). Low familiarity and similar ‘group strength’ between opponents increase the intensity of intergroup interactions in mountain gorillas (Gorilla beringei beringei)
  31. Opie, C. et al. (2013) Male infanticide leads to social monogamy in primates. 
  32. Petersdorf et al (2019) Sexual selection in the Kinda baboon
  33. Pines et al (2011). Alternative Routes to the Leader Male Role in a Multi-Level Society: Follower vs. Solitary Male Strategies and Outcomes in Hamadryas Baboons
  34. Pisor & Surbeck (2019). The evolution of intergroup tolerance in nonhuman primates and humans
  35. Qi et al (2014). Satellite telemetry and social modeling offer new insights into the origin of primate multilevel societies
  36. Qi et al (2017). Male cooperation for breeding opportunities
  37. Qi et al (2020). Multilevel societies facilitate infanticide avoidance through increased extrapair matings
  38. Saramaki et al (2014). Persistence of social signatures in human communication
  39. Shultz et al (2011). Stepwise evolution of stable sociality in primates 
  40. Silk (2002). Using the ‘f’-word in primatology. 
  41. Stead & Teichroeb (2019). A multi-level society comprised of one-male and multi-male core units in an African colobine (Colobus angolensis ruwenzorii)
  42. Snyder-Mackler et al (2011). Defining Higher Levels in the Multilevel Societies of Geladas (Theropithecus gelada)
  43. Sutcliffe et al (2016). Modelling the Evolution of Social Structure
  44. Swedell & Schreier (2009). Male Aggression towards Females in Hamadryas Baboons: Conditioning, Coercion, and Control
  45. Swedell et al (2011). Female ‘‘Dispersal’’ in Hamadryas Baboons: Transfer Among Social Units in a Multilevel Society
  46. Xiang et al (2014). Males collectively defend their one‐male units against bachelor males in a multi‐level primate society

[Excerpt] Collapse of Supermind

Part Of: Culture sequence
Excerpt From: Henrich (2015). Secret of Our Success
Content Summary: 1000 words, 5 min read

The loss of adaptive cultural information can result from two different processes. The first is what we saw happen to the Polar Inuit: a random shock (an epidemic) happened to strike the most knowledgeable members of the community, wiping out a chunk of their cultural know-how. Because it removed the kayak (their transportation) from their cultural repertoire and they were already geographically very isolated, they went into a slow downward spiral as their populations dwindled due to the technological losses. This kind of phenomena may be common.

The other process is more subtle and I suspect more important. If someone is copying the techniques and practices of a highly skilled and knowledgeable expert, they will often end up with a level of skill or knowledge that is less than that of the expert they are copying. The reason is that some information was lost every generation, because copies are usually worse than the originals. Cumulative cultural evolution has to fight against this force and it is best able to do so in larger populations that are highly socially interconnected. The key is that most individuals end up worse than the models they are learning from. However, some few individuals, whether by luck, fierce practice, or intentional invention, end up better than their teachers. 

Larger populations can overcome the inherent loss of information in cultural transmission because if more individuals are trying to learn something, there’s a better chance that someone will end up with knowledge or skills that are at least as good as, or better than, those of the model they are learning from. Interconnectedness is important because it means more individuals have a chance to access the most skilled or successful models, and thereby have a chance to exceed them. 

The Tasmanian Effect

These ideas first struck me when I was reading about the aboriginal inhabitants of the island of Tasmania. Roughly four-fifths the size of Ireland and comparable to Sri Lanka, Tasmania lies about 200 kilometers south of Victoria, Australia. When the earliest European explorers made contact with the Tasmanians in the late eighteenth century, they discovered a population of hunter-gatherers equipped with the simplest toolkit of any society ever encountered (by Europeans). To hunt and fight, men used only a one-piece spear, rocks, and throwing clubs. For watercraft, the Tasmanians relied on leaky reed rafts and lacked paddles. To ford rivers, women would swim the raft across, towing their husbands and offspring. In the cool maritime climate, Tasmanians slung wallaby skins over their shoulders and applied grease to their exposed skin. Curiously, the Tasmanians did not catch or eat any fish, despite fish being plentiful around the island. They drank from skulls and may even have lost the ability to make fire. In all, the Tasmanian toolkit consisted of only about twenty-four items.

To put this simplicity into perspective, let’s consider the Pama-Nyungan-speaking Aborigines who were contemporary with the Tasmanians in the eighteenth century, and lived just across the Bass Strait in Victoria. These Aborigines possessed the entire Tasmanian toolkit plus hundreds of additional specialized tools, including a fine array of bone tools, leisters, spear throwers, boomerangs, mounted adzes (for woodworking), many multipart tools, a variety of nets for birds, fish, and wallabies, sewn-bark canoes with paddles, string bags, ground-edge axes, and wooden bowls for drinking. For clothing, rather than draped wallaby skins and grease, the Aborigines wrapped themselves in snugly fitting possum-skin cloaks, sewn and tailored with bone awls and needles. For fishing, the aboriginal populations used shellfish hooks, nets, traps, and fishing spears. Somehow, the Tasmanians ended up with a much simpler toolkit than did their contemporary cousins just across the Bass Strait.

The Tasmanian toolkit is simple even when compared to that of many ancient Paleolithic societies. The archeological record from many parts of the world, going back tens and even hundreds of thousands of years, reveals the emergence of more-complex toolkits than those possessed by the Tasmanians at the time of European contact. Tasmanian stone tools are much cruder than many of the tools found in Europe made by many Neanderthals. The Tasmanians lacked bone tools, yet elsewhere finely crafted bone harpoon points date to at least 89,000 years ago. Similarly, stone points for spears date to a half a million years ago, well before the emergence of our species. Hafted tools date back before the origins of our species, 200,000 years ago. 

Slow-Motion Collapse

The puzzle deepens when we realize that Tasmania was connected to the rest of Australia until about 12,000 years ago. As the seas rose, the Bass Strait flooded and transformed Tasmania from an Australian peninsula to an island. Until this isolation, the archaeological remains left by Tasmanians cannot be distinguished in terms of complexity from those found in Australia. With their isolation, Tasmanians began to lose complex tools. The number of bone tools gradually dwindled until about 3,500 years ago, when they vanished entirely. As evidenced by fish bones, at least some ancient Tasmanian groups probably relied heavily on fish. But, gradually. fish dwindle and disappear from the record. By the time Captain Cook’s men offered freshly caught fish from the bountiful waters around the island in 1777, the Tasmanians reacted with disgust; yet, they gladly took and ate the bread Cook offered. 

By isolating Tasmanians for eight to ten millennia, the rising seas cut them off from the vast social networks of Australia, suddenly shrinking their collective brains (supermind). A gradual loss of their most complex and difficult to learn skills and technologies ensued. 

Supermind Over Mind

In class, I show my undergraduates unlabeled pictures of four different stone toolkits from (1) eighteenth-century Tasmanians, (2) seventeenth-century Australian Aborigines, (3) Neanderthals, and (4) late Paleolithic modern-looking humans (30,000 years ago). I ask them to assess the cognitive abilities of the toolmakers by looking at the tools. My students always rate the Tasmanians and Neanderthals as less cognitively sophisticated than both the seventeenth-century Australian Aborigines and the late Paleolithic toolmakers. Of course, there’s no reason to suspect any innate cognitive differences between Tasmanians and Aborigines, who only became separate populations after the Bass Strait flooded. 

Because most Neanderthal groups possess a toolkit substantially less complex than the more modern-looking African intruders (our ancestors), the assumption has often been that Neanderthals suffered some innate cognitive deficits. 

In primates, the strongest predictor of cognitive abilities across species is overall brain size. Consequently, it’s not implausible that we were dumber than the bigger-brained Neanderthals. However, they had larger collective brains capable of generating greater cumulative cultural evolution.

Works Cited

  • Gott (2002). Fire making in Tasmania: Absence of evidence is not evidence
  • Henrich (2004). Demography and cultural evolution: Why adaptive cultural processes produced malapative losses in Tasmania
  • Rivers “The Disappearance of Useful Arts”
  • Jones (1977). The Tasmanian Paradox.
  • Jones (1995). Tasmanian Archaeology: Establishing the Sequences

The Evolution of God

Part Of: Religion sequence
Followup To: The cognitive basis of theism, Supernatural Punishment Hypothesis
Content Summary: 2900 words, 29 min read

NRMs and Cultural Group Evolution

In 2015, 4.11 billion people (56%) participate in the Abrahamic religious traditions (Judaism, Christianity, Islam). A further 1.6 billion people (22%) participated in karmic religions (Hinduism, Buddhism). 16% of people are unaffiliated, and most of these in China. Only 7% of the world adhere to other faiths. 

These five religions, the world religions, lay claim to 92% of the faithful. But the number of other religions is in the tens of thousands. On average, three new religious movements (NRMs) sprout every day. On average, these groups last 25 years (Sosis 2000). Yet some achieve striking growth. For example, the Mormon church has seen an explosive growth of 10% per decade, roughly equal to the growth rate of the Christian church in the Roman Empire. Who knows what religious life will look like, a century from now?

The religious landscape reverberates with a Darwinian restlessness. It is easy to miss this dynamic process, because a few outlier religious movements have cornered the cultural marketplace. But their monopoly is not guaranteed.

Two Interlocking Mysteries

Consider the following mysteries:

  1. Foraging tribes had a soft ceiling: groups had difficulty sustaining more than 200 people before fissions occurred. Yet farmers managed to live in much larger groups. How?
  2. The gods of hunter-gatherers tended to be weak, whimsical, and not particularly moral. Yet the gods of agriculturalists became interested in certain kinds of human actions, and slowly  developed greater powers to both monitor adherents (e.g., omniscience) and punish proper behavior (hell or karma). Why?

What is the relationship between these two questions? And why does social success correlate so strongly with religious morality?

Many anthropologists look at economic and political developments to explain the social success of farming communities. On this cultural ornament theory of religion, theistic beliefs are causally inert practices: bringing solace and meaning, but disconnected from social and political outcomes.

But we have already seen evidence that religions can generate prosocial behavior. And we also saw that perceptions of supernatural monitoring & punishment can drive this effect. It is natural to suppose that increasingly powerful, and morally concerned deities enhance these effects.

Why did this happen? Recall the golden rule of cultural group selection:

Within-group cooperation is essential to promote between-group competition. 

Organized religion was the fuel that powered the social complexification of the Neolithic. This is the Big Gods Hypothesis (Norenzayan 2015). 

Göbekli Tepe is the site of the world’s oldest temple (8000 BCE), which recent findings reveal housed a skull cult (Greski et al 2017). The site seems to have been built by foragers; which is astounding coordinative feat, especially since its construction would have required some 500 people working in tandem. The site attracted worshippers from up to 90 miles away, and the traffic it generated plausibly smoothed the way for the first cities. More significantly, the site is 20 miles away from Karaca Dağ, the site where wheat was domesticated for the first time. Would the Neolithic Agricultural Revolution have been possible without the advent of organized religion?

While not conclusive, Göbekli Tepe is precisely the kind of site we would expect to find if religious innovations were to precede social ratcheting events. But the Big Gods hypothesis is also consistent with religious innovations occurring afterwards too. Do megasocieties cause (protective) Big Gods, or do Big Gods enable megasocieties? While Whitehouse et al (2021) argue the former, Breheim et al (2021) argue the latter.

Big Gods & Societal Outcomes

How do we know that moralizing religion played a role in sociopolitical development? The first place to look would be at large historical & anthropological datasets, gleaned from the early qualitative ethnographies.

  • Seshat: The Global History Databank
  • Ethnographic Atlas (EA) has data for 1267 societies; and Standard Cross-Cultural Sample (SCCS); a 186 society sample of EA
  • Human Relations Area Files (HRAF)

Swanson (1960) was the first person to investigate what he termed Moralizing High Gods (MHG) in the EA. In a more recent analysis, Johnson (2005) found in a SCCS sample of 186 societies that moralizing high gods was highly correlated with ten different measures of cooperation, including community size, policing, norm compliance, and food sharing. These analyses arguably suffer from Galton’s Problem: unwarranted independence assumptions.

A recent attempt to work-around this problem is provided by comparative phylogenetics. Linguists have long known that the similarities between languages can be quantified as a tree. As social groups fission, migrate, and lose contact, their language systems slowly diverge. 

Darwin himself used these findings to inform his theory of common descent. Just as genetic cladograms reveal the secrets of natural selection, language trees can divulge the secrets of cultural group selection. More specifically, Watts et al (2015) used language phylogenies to reverse engineer the historical relationships between 96 Austronesian cultures. In this historically-sensitive dataset, the relationship between supernatural punishment and high political complexity is striking.

So far, we’ve discussed how moralizing gods tend to appear more in agricultural societies than foraging societies. But other modes of subsistence also exist. Peoples & Marlowe (2012) found that pastoralism (living off of domesticated animals) even more strongly gravitates to moralizing high gods. Because pastoralists are more warlike and more inequal than agriculturalists, the need for religion-induced cohesion is even more pronounced.

Big Gods & Individual Cooperation

We’ve seen societal outcomes correlated with big gods. What about individual behavior? Are believers more likely to cooperate with one another, for the betterment of their group?

The following research makes heavy use of three games:

  1. Public Goods Game (PGG) explores questions of cooperation
  2. Ultimatum Game (UG) explores questions of fairness
  3. Random Allocation Game (RAG) explores cheating behaviors

We’ve seen prosocial religions occur in larger societies. Henrich et al (2010) took these economic games (including the Ultimatum Game) to fifteen societies that span the gamut of human existence. People who lived in very large communities (5000+ people) were much more willing to punish resource distributions that were unfair (not $50 each). 

These games were conducted with villagers playing one another. Thus, these games were informed by relationships and reputation. But increasing community size requires cooperation among strangers. Did moralizing gods help bind complex multi-ethnic empires at vast geographic scales? 

To get insight into this question, Purzycki et al (2016) examined whether moralizing gods improved cooperation with strangers who share your faith. In a sample of 2228 participants from 15 populations, they found evidence of such cooperation. They also found that, as beliefs in moralistic punishment intensified, so too did cooperative behavior.

Doesn’t this discredit our facultative religious prosociality hypothesis, put forward in Supernatural Punishment Hypothesis? There, we discussed that believers don’t behave more cooperatively than non-believers on average; they only do so when their religious practices are primed. This is measured in, among other things, willingness to punish unfair behavior in economic games.

The research we reviewed then, however, only apply in WEIRD societies. In many developing nations, participation in world religion does consistently produce a cooperative advantage. Hermann et al (2008) found that the rule of law, and strong norms of civic cooperation are responsible for “raising the sanity waterline”, and equalizing the belief advantage in many developed secular societies. 

Competition Boosters

Henrich (2015) describes five basic mechanisms of intergroup competition:

  1. Group survival w/o conflict
  2. War & Raiding
  3. Differential migration
  4. Prestige-based group transmission
  5. Differential reproduction

If religious practices evolved to boost said competition, we should expect its signature on all of these mechanisms. And that is precisely what we find.

First, let’s consider group longevity. Sosis (2000) examined data from 112 secular and 88 religious utopian communes. He found that, after controlling for commune size, year of founding etc, that for any given year, religious communes were four times more likely to survive. 

Second, consider direct competition. We’ve already seen that world religions promote cooperation towards the local co-religionists, and distant co-religionists. What about those outside the faith? Norenzayan et al (2016) predicted that 

  1. In societies with lots of intergroup conflict, co-religionists should be hostile to outgroup members (to facilitate direct competition)
  2. In societies with less conflict, co-religionists should be more generous to outgroup members (to gain converts)

Lang et al (2019) confirmed this prediction. Less competition leads religionists to behave altruistically even to the outgroup.  

Religious ritual also seems to play a role in support for suicide attacks (and, I would predict, also support for hawkish foreign policy). Ginges et al (2009) found that participation in religious services predicted support for terrorist attacks in both Israeli and Palestinian subjects. This relationship is easy to explain if we conceive of religion as subject to cultural group selection. But they also found that frequency of prayer was statistically unrelated to this attitude (again hinting at separate mechanisms within the complex adaptive system we call “religion”).

Third, world religions invest much more heavily in conversion tactics. 

Finally, modern religions have a strong pro-natalism ideologies; the various stances of the Catholic Church on contraception, abortion, and the centrality of family are but one example. 

Karma & Punishment Reification

Religion is about more than just the gods and morality. Arguably more central to religion is ritual, which also comes in secular varieties (marriage, inauguration ceremonies, etc). Other subprocesses of religion include taboo, mythology, sanctity, authority, and autobiographical meaning (Sosis 2019). These eight processes have different effects, and different historical trajectories. 

For example, Whitehouse’s (2004) mode theory describes two kinds of ritual: episodic rituals (infrequent, often dysphoric events), to doctrinal rituals (frequent, more emotionally neutral gatherings). 

Episodic rituals were used by hunter-gatherers, but as farming groups became larger, rituals became increasingly doctrinal. These two forms had different psychological effects: episodic rituals promote identity fusion (and with it, a willingness to engage in extreme acts of self-sacrifice), doctrinal rituals facilitated a more conceptual sense of group identification (Whitehouse et al 2014).

We’ve spent a lot of time discussing the cognitive basis of theism, and how the fluency of disembodied-mind concepts can be exploited to promote prosocial behavior. But the above discussion of ritual shows there are many other “cracks in our psychological armor” that religious processes can exploit, driven by the eternal flame of group competition.

The Abrahamic religions use God-beliefs to promote prosociality. What do we make of karmic religions? Consider Sarkissian (2015)’s discussion of Chinese civilization:

Shang Di (Lord on High) plays the role of a supernatural monitor during the Shang Dynasty (1600–1046 BCE)… However, after the conquest of the Shang (1045 BCE), Shang Di is replaced by the notion of Tian (or heaven). Tian appears, at the outset, as the same entity as the former Shang Di. Yet Tian slowly loses its anthropomorphic characteristics and becomes less interested in human affairs. Eventually, Tian is significantly naturalized, taken to refer as much to the patterns and propensities inherent in the natural world as to any deity. 

We know that karmic religions (including Buddhism and Hinduism) promote prosociality. But how? How does karma promote prosociality?

White et al (2020) present the karma personification hypothesis, that (contra theological correctness), karma has been personified in the practiced religion of believers, and leverages the same sense of social monitoring. They adduce evidence that, for some believers some of the time, karma is conceived in this way.

But alternatives exist. Consider Nietzsche (1884):

What actually arouses indignation over suffering is not the suffering itself, but the senselessness of suffering: but neither for the Christian, who saw in suffering a whole, hidden machinery of salvation, nor for naïve man in ancient times, who saw all suffering in relation to spectators or to instigators of suffering, was there any such senseless suffering. In order to rid the world of unseen suffering, people were then practically obliged to invent gods and intermediate beings at every level, in short, something that would not miss out on an interesting spectacle of pain so easily.”

Nietzsche is putting his finger on Belief in a Just World (BJW) (Hafer & Rubel 2015) and the related phenomenon of immanent justice reasoning (Callan et al 2014). Since punishment often follows social transgressions, people seem to attribute random misfortune to moral failings (victim blaming!): 

People drawing causal links between random misfortune and their own and others’ moral shortcomings, such as a boy who believed he failed an eye examination because he glanced through a Playboy magazine 3 days earlier, or a man who believed his friend became paraplegic because he was a “cocky guy” and “never really took the time to worry about the people who couldn’t keep up” 

Social psychology research has revealed that these intuitions are innate, and thus expressed universally. A few examples:

It may be that White et al (2020) is correct, and that karmic religions are connected by monitoring by supernatural monitors. But I suspect the answer is different, that the cognitive basis of karmic religions is just different. All human beings are subject to immanent justice and mind-body dualistic intuitions; the cultural winnowing forces simply elaborate these intuitions differently, based on circumstance.

Supernatural monitoring and immanent justice reasoning have one thing in common: punishment. In contrast to the one-substrate MHG hypothesis, let’s call this two-substrate view the Broad Supernatural Punishment (BSP) hypothesis. For an excellent discussion of the relative virtues of these theories, see Raffield et al (2019).

Three Schools

The arguments of this sequence was heavily influenced by Norenzayan (2015) and Norenzayan et al (2016), with a few divergences (especially in the Karma section above). But I want to note other theories on offer. In fact, evolutionary accounts of religion can be organized into three camps:

  1. By-Product theories are often championed by cognitive scientists. These theories focus on religious universals. 
  2. Adaptationist theories are often championed by biologists. These theories tend to focus on social impacts of religion. 
  3. Cultural Evolutionary theories are often championed by anthropologists. These theories tend to focus on biodiversity.

Given their different backgrounds, these different schools tend to discover different, complementary facets of religious phenomena. Modern theories tend to be more synthetic, drawing evidence across these traditional lines. The cultural group selection model presented here, for example, is happy to build on psychological data from by-product theorists (see Cognitive Basis of Theism) and sociological data from adaptationists (see The Supernatural Punishment Hypothesis). 

In fact, as mentioned above, there is an adaptationist version of the cultural evolutionary Big Gods hypothesis, put forward here. Johnson & Kruger (2004) first put forward what they termed the Supernatural Punishment hypothesis, as an adaptationist theory of religion. Drawing on quite similar datasets, the Supernatural Punishment hypothesis is comfortable interpreting Holocene-era religious developments (e.g., the Axial Age) as being non-genetic. But Johnson also avows a genetic adaptation kickstarted our earliest religious behaviors in the Paleolithic. 

All of which raises the question, do apes possess intuitions about mind-body dualism? Do they engage in magical thinking? What about immanent justice reasoning? I am not aware of much research on this question to date.


If you had been born before the Neolithic Revolution, you would have almost certainly worshipped weak, whimsical, and not particularly moral deities. Everyone did.

Yet over time, God evolved to become interested in certain kinds of human behavior, and slowly developed greater powers to both monitor adherents (e.g., omniscience) and harsher punishments of improper behavior (hell, or eons of karma).

Why did religion become entwined with morality? Because it increasingly played a role as glue, that stabilized communities.

Intuitions about disembodied minds, along with other “cracks in our psychological armor”, were mined by religion for their ability to induce accountability & fear of punishment. All of this was done in service to the eternal flame of group competition.

Until next time.


Two Interlocking Mysteries

  • Beheim et al (2021). Treatment of missing data determines conclusions regarding moralizing gods.
  • Roes & Raymond (2003). Belief in moralizing gods.
  • Norenzayan (2015). Big Gods: How Religion Transformed Cooperation and Conflict
  • Gresky et al (2017). Modified human crania from Göbekli Tepe provide evidence for a new form of Neolithic skull cult
  • Whitehouse et al (2019). Big Gods did not drive the rise of big societies throughout world history.

Anthropological Findings

  • Johnson (2005). God’s Punishment and Public Goods: A Test of the Supernatural Punishment Hypothesis in 186 World Cultures 
  • Peoples & Marlowe (2012). Subsistence and the Evolution of Religion 
  • Swanson (1960). The Birth of the Gods
  • Turchin et al (2019). An Introduction to Seshat: Global History Databank 
  • Watts et al (2015). Broad supernatural punishment but not moralizing high gods precede the evolution of political complexity in Austronesia

Psychological Findings

  • Hermann et al (2008). Antisocial Punishment Across Societies
  • Henrich et al (2010). Markets, Religion, Community Size, and the Evolution of Fairness and Punishment
  • Henrich (2015). Culture and social behavior 
  • Norenzayan et al (2016). The cultural evolution of prosocial religions. 
  • Purzycki et al (2016). Moralistic gods, supernatural punishment and the expansion of human sociality

Competitive Boosters

  • Ginges et al (2009). Religion and Support for Suicide Attacks
  • Henrich (2015). The Secret of Our Success: How Culture Is Driving Human Evolution, Domesticating Our Species, and Making Us Smarter
  • Lang et al (2019). Moralizing gods, impartiality and religious parochialism across 15 societies. 
  • Sosis (2000). Religion and Intragroup Cooperation: Preliminary Results of a Comparative Analysis of Utopian Communities

The Role of Karma

  • Atkinson & Whitehouse (2011). The cultural morphospace of ritual form: Examining modes of religiosity cross-culturally
  • Callan et al (2014). Immanent Justice Reasoning: Theory, Research, and Current Directions
  • Hafer & Rubel (2015). The Why and How of Defending Belief in a Just World 
  • Nietzsche (1887).  Genealogy of Morals
  • Raffield et al (2019). Religious belief and cooperation: a view from Viking Age Scandinavia.
  • Sarkissian (2015). Supernatural, social, and self-monitoring in the scaling-up of Chinese civilization.
  • Sosis (2019). The building blocks of religious systems: Approaching religion as a complex adaptive system
  • White et al (2020). Cognitive pathways to belief in karma and belief in God
  • Whitehouse (2004). Modes of religiosity
  • Whitehouse et al (2014). The ties that bind us: Ritual, fusion, and identification

A Third Way

  • Johnson & Kruger (2004). The good of wrath: supernatural punishment and the evolution of cooperation.

The Supernatural Punishment Hypothesis

Part Of: Religion sequence
Followup To: The cognitive basis of religion
Content Summary: 2300 words, 23 min read


Last time, we discussed how various mindreading intuitions explain why religions overwhelmingly endorse thoughts of disembodied minds, the afterlife, etc. 

One noticeable absence in that discussion is morality. Religious dogma is highly concerned with morality, and religions often claim to have made their members better people. Is there some kind of necessary relationship between mind-body dualism and ethics? 

Today, I will present evidence suggesting that one particular aspect of theism, namely belief in supernatural monitoring & punishment, is responsible for most of the moral virtues seen in the religious. This is the supernatural punishment hypothesis.

Social Monitoring

Human beings possess norm psychology, enforced by gossip-mediated reputation and altruistic punishment. While we often internalize norms (especially the guilt response of the idiocentric), we are much more likely to engage in self-interested behavior if no one is watching. 

This is in fact the case. Anonymity significantly increases selfish behavior (Hoffman et al 1994). Playing economic games under low light also promotes selfishness (Zhong et al 2010); this darkness effect is statistically mediated by feelings of anonymity.

Self-awareness theory holds that people can oscillate between two different states of self-awareness. When people view themselves as a target of social scrutiny, they experience public self-awareness; in contrast, private self-awareness occurs when attention is directed inward. Reminders of social monitoring uniquely heightens public self-awareness. 

These effects aren’t subtle. Monitoring detection is absolutely essential to human social life. Our subconscious response to eyes remains strong even if we consciously know the eyes aren’t connected to minds. In a classic experiment, Bateson et al (2006) measured voluntary donations given to the office coffee fund. By simply altering a picture adjacent to the coffee maker (from flower pictures to eye pictures), prosocial donations increased when people were around pictures of eyes.

Watched people are nice people.

Supernatural Monitoring

Human social cognition produces intuitions about disembodied minds. Despite their immateriality, we relate to gods as we do other agents. Does the thought of God make us behave like we do when other humans watch us?

Yes. Supernatural monitoring is a special case of social monitoring. We can see this in e.g. the Dictator Game. In the game, one person is given $10, and must decide how much to give to the other player ($0 is maximally selfish, $5 is often considered more “fair”).

Both believers and atheists offer about $2 on their own accord. But, when thoughts of God are unconsciously primed, the offer of believers increases dramatically. 

If God-primes simply activated stereotypes of prosocial behavior (an ideomotor response), we would expect atheists to respond too. But the effect only works for those who believe God is watching them.

We can also see this supernatural monitoring effect in children. Piazza et al (2011) involved a game with an apparently easy way to cheat (detected via hidden camera). Children playing this game cheated much less when they were told an invisible agent, “Princess Alice” was sitting in a nearby chair.

Shariff et al (2015) performs a meta-analysis over 25 religious priming studies, and found that religious primes reliably elicit prosocial behavior.

Just like the presence of a video camera, experimental reminders of gods increase public self-awareness but not private self-awareness. For Christians reporting strong religious belief, the effect on public self-awareness of thinking about God is statistically indistinguishable from the effect of thinking about being judged by one’s peers (Gervais & Norenzayan 2012, Study 1). 

Feeling watched increases prosocial behavior, but it also leads people to put their best foot forward, even at the expense of honesty. Socially desirable responding, in particular, is a potentially useful way to test whether priming religious concepts triggers mind perception or merely makes people act in accordance with prosocial norms and stereotypes. If priming gods merely makes prosocial stereotypes and norms salient, then they should perhaps increase honesty (which translates into fewer socially desirable responses). On the other hand, if reminders of gods make people feel watched, then people should instead respond  in more socially desirable ways. Recent evidence supports the latter hypothesis. Believers exhibit significantly more socially desirable, dishonest responding after being primed with god concepts (Gervais & Norenzayan, 2012, Study 3). 

Supernatural Punishment

Supernatural monitoring promotes religious prosociality. Why? Which specific elements within our religious ideas creates such an effect?

The stick looms larger than the carrot. Strong evidence suggests the threat of punishment is the theological element that does the heavy lifting. And this makes sense: in earthly settings, punishment is the lifeblood of intragroup cooperation.

Yilmaz & Bahcekapili (2016) and Shariff & Norenzayan (2011) found that, while belief in gods are largely irrelevant, priming beliefs in supernatural punishment causes lower individual rates of cheating. DeBono et al (2015) found a related effect: reminders of God’s forgiveness actually increases cheating behavior, relative to control conditions.

At the national scale, after controlling for relevant variables such as GDP and education, belief in hell is strongly associated with lower crime rates (Shariff & Rhemtulla 2012). But such beliefs also come at a price. Belief in hell is also associated with lower overall life satisfaction and day-to-day measures of wellbeing (Shariff & Aknin 2014). 

If hell is the necessary ingredient for good behavior, why believe in heaven? While hell might be better at getting people to be good, heaven is better at making them feel good. Heaven will get you in the door, hell will ensure the door is repaired in a timely fashion.

Facultative Prosociality

Most of the individual-level causal evidence above is based on priming studies. These studies are quite robust, as revealed in meta-analyses such as Shariff et al (2015).

But what about when believers aren’t reminded of their faith? Do they consistently act better than nonbelievers? Is prosociality a personality trait, strengthened by religious praxis?

The answer is complicated. But there is some reason to think, at least in WEIRD nations, belief doesn’t increase moral behavior. 

First, consider cheating. Are religious people less likely to cheat? Smith et al (1975) describes how research has consistently failed to find any substantial difference based on religiosity.

Second, consider altruism. The Parable of the Good Samaritan describes people passing by an injured person in need; helping – even when it is inconvenient – seems a useful way to operationalize altruism. But when Darley & Batons (1973) recreated a modern-day Good Samaritan scenario, religious people were no more likely to help! In fact, the only two variables that predicted helping were sex (females show a higher frequency of altruistic behavior) and situational factors (people told to hurry were much less likely to help). 

Religion does produce prosocial behavior, as explained by the supernatural punishment hypothesis. But in WEIRD nations, it seems this prosociality is restricted to times when believers are reminded of their faith. For Christians, this explains the Sunday effect

  • Malhotra (2010) found that Christians are much more likely to give to charity on Sundays.
  • Edelman (2009) found that, while Christians use as much porn as non-Christians, they use less on Sundays (compensating later in the week).

This effect generalizes to other faiths:

  • Duhaine (2015) found that Moslems are much more likely to give to charity when asked during a call to prayer.
  • Xygalatas (2013) found that Hindus are much less likely to act selfishly in an economic game conducted within a temple.

What good is facultative (situation-dependent) prosociality? Consider this quote from Henrich (2020).

A far more important source of divine punishment arose from the violation of sacred oaths taken in the name of particular gods while signing commercial contracts, making sales, or assuming public offices. In Athens, as in many parts of the Greek world, the marketplace was filled with altars to various gods. Merchants were required to swear sacred oaths before these altars to affirm the authenticity and quality of their goods. Athenians’ intense reliance on the gods, and on such oaths, may help explain their enduring reputation for trustworthiness in both business and treaty-making. 

Religion is more in the situation than in the person.

In Gods We Trust

Religion is a team sport. Enhanced individual prosociality should have group-level consequences. 

Recall our previous discussion of the Prisoner’s Dilemma. While that particular payoff structure may not be representative of human social dynamics (Hawk-Dove and Biological Markets are more incisive), the general point holds: cooperation is the most important challenge of human social life

If religion promotes cooperation, that’s one thing. But if cooperators manage to find each other (costly and/or credible signals) and prefer interactions with one another (trust), then their groups will reap the rewards. You can see this principle illustrated in spatial evolutionary games:

Note that cooperators can only seek each other in relationally mobile (i.e., individualistic) societies. Using trust signals to engage with cooperators is less relevant in collectivist societies, which employs reputation (Sosis 2005).

There exist two ways to operationalize trust:

  1. Attitudinal trust is an attitude of confidence in the reliability of another person or institution. 
  2. Behavioral trust is a costly and risky investment in a person or entity, with the future expectation of cooperation. 

Attitudinal trust for religious participants is well attested. A worldwide survey of 81 countries representing 85 percent of the world’s population, conducted between 1999 and 2002 found that almost two-thirds of all participants said they trust religion, compared to only half who trust their government, and only about one-third who trust political parties.

The religious also elicit strong levels of behavioral trust (Tan & Vogel 2008):

  1. More money was forwarded to responders perceived to be religious. 
  2. While believers strongly trusted their own kind, nonbelievers were either, if anything, mildly trusting of believers.
  3. Believers were in fact more likely to cooperate.

Anti-Atheist Prejudice

Consider the Traveling Salesman problem:

Max Weber was sitting next to a traveling salesman when the conversation turned to religion. In a now famous quote, the man said: “Sir for my part everybody may believe or not believe as he pleases; but if I saw a farmer or a businessman not belonging to any church at all, I wouldn’t trust him with fifty cents. Why pay me, if he doesn’t believe in anything? 

Social scientists have long noted that Americans are less accepting of atheists than of any other groups, and by a wide margin. This anti-atheist prejudice is widely expressed internationally, but it of course varies by country. Consider that only one US legislator has come out as atheist:

On March 2, 2007, long-time congressman Pete Stark, Democrat from California, made history. He did not author a far-reaching legislation that created jobs, cleaned the air, or shaped foreign policy. He was simply the first member of the US Congress to come out as an atheist. In 2012, Stark lost to fellow Democrat Eric Swalwell Jr., who publicly attacked Stark’s atheism. 

My first impulse was to attribute anti-atheist prejudice to a generic stereotyping mechanism. But if you examine its characteristics in detail, it turns out to behave quite different from other stigmas:

The supernatural punishment hypothesis is able to explain this rather peculiar psychological profile.

If sincere belief in a morally concerned deity serves as a reliable cooperative signal, it follows that those who explicitly deny the existence of God are inadvertently sending the wrong signal: they are being perceived as subversive non-cooperators by the religious. 

I’ll close by noting that there are three known ways to reduce anti-atheist prejudice:

  1. Exposure to or reminders of strong institutions that create prosocial norms
  2. Exposure to or reminders of atheists’ prevalence 
  3. The decline of religiosity in a given society


Today, we covered five topics:

  1. Social monitoring: Watched people are nice people
  2. Supernatural monitoring: God is watching you.
  3. Supernatural punishment: Hell is stronger than heaven
  4. Facultative prosociality: Religion is more in the situation than in the person.
  5. In Gods We Trust: Trust people who trust in god.

To be clear, supernatural monitoring is not the only source of prosociality in religion. Self-control (McCullough & Willoughby 2009) is an extremely important factor, for example. The supernatural punishment hypothesis merely posits that this intuitive mechanism is a) specific to believers, and b) intuitively held & deeply powerful. 

Until next time.


Social monitoring

  • Bateson et al (2006). Cues of being watched enhance cooperation in a real-world setting.
  • Hoffman et al (1994). Preferences, property rights, and anonymity in bargaining games.
  • Zhong et al (2010). A good lamp is the best police: Darkness increases dishonesty and self-interested behavior

Supernatural Monitoring

  • Atkinson & Beliefs about God, the afterlife and morality support the role of supernatural policing in human cooperation
  • Gervais & Norenzayan (2012). Like a camera in the sky? Thinking about God increases public self-awareness and socially desirable responding
  • Piazza et al (2011). “Princess Alice is watching you”: Children’s belief in an invisible person inhibits cheating.
  • Shariff et al (2015). Religious Priming: A meta-analysis with a focus on religious prosociality.

Situational Prosociality & Sunday Effect

  • Darley & Batons (1973). “From Jerusalem to Jericho”: A study of situational and dispositional variables in helping behavior
  • Edelman (2009). Red light states: who buys online adult entertainment?
  • Henrich (2020). The WEIRDest People in the World: How the West Became Psychologically Peculiar and Particularly Prosperous
  • Malhotra (2008). Are religious people nicer? Religious salience and the “Sunday effect” on prosocial behavior.
  • Shariff (2015). Does religion increase moral behavior? 
  • Smith et al (1975). Faith Without Works: Jesus People, Resistance to Temptation, and Altruism 
  • Duhaime (2015). Is the call to prayer a call to cooperate? A field experiment on the impact of religious salience on prosocial behavior

Hell is Stronger than Heaven

  • DeBono et al (2017). Forgive us our trespasses: Priming a forgiving (but not a punishing) god increases unethical behavior
  • Shariff & Rhemtulla (2012). Divergent effects on belief in heaven and hell on national crime rates.
  • Shariff & Aknin (2014). The Emotional Toll of Hell: Cross-National and Experimental Evidence for the Negative Well-Being Effects of Hell Beliefs
  • Shariff & Norenzayan (2011). Mean gods make good people: Different views of god predict cheating behavior
  • Yilmaz & Bahcekapili (2016). Supernatural and secular monitors promote human cooperation only if they remind of punishment

Trust & Anti-Atheist Prejudice

  • Sosis (2005).  Does Religion Promote Trust? The Role of Signaling, Reputation, and Punishment
  • Shigaki et al (2012). Referring to the social performance promotes cooperation in spatial prisoner’s dilemma games
  • Tan & Vogel (2008). Religion and Trust: An Experimental Study


  • McCullough & Willoughby (2009). Religion, Self-Regulation, and Self-Control: Associations, Explanations, and Implications

The cognitive basis of theism

Part Of: Religion sequence
Related To: The Logic of Mindreading
Content Summary: 3000 words, 30 min read

Religion as Natural

Most human beings in recorded history have participated in religion

There is no consensus definition of religion; but we can still put our finger on a family resemblance. Theistic religions tend to…

  1. Include a belief in spiritual beings, such as ghosts, angels, ancestor spirits, and so on. These entities often have mental lives, but no physical form. 
  2. Posit an afterlife.
  3. Affirm the purposeful creation of the universe, including humans and other animals. 

You are not going to find a place, anywhere, where such notions feel absurd. Yet despite the ubiquity and family resemblances, the content of religious traditions vary immensely across cultures and across history. 

Perhaps religion is similar to language. All societies have at least one language; all societies have at least one religion. Also like language, religion is not present at birth. It develops instead through immersion in a social environment. The specific language or religion that a child develops is determined by the culture in which the child is raised, not by genes or the physical environment. But there are universals of language. Every language has words and sentences, as well as principles of phonology, morphology, and syntax. And as we saw above, there are also universals of religion. 

In sum, the ubiquity and family resemblance of religious traditions point to a shared cognitive basis, but theodiversity reminds us these intuitions support constructs subject to cultural evolution.

Today, we will be exploring the cognitive basis of religion. Unlike language, a unified faculty which directly promotes biological fitness, we will learn how religious instincts are byproducts of human social machinery. 

Mind perception enables God perception

There is a cartoon depicting an alarmed husband telling his visibly upset wife, “Of course I care about how you imagined I thought you perceived I wanted you to feel.” While most social interactions are fortunately not as convoluted, social life does require mindreading. You can think of the mindreading faculty as a little machine in your brain, which guesses at the beliefs and desires of others.

Across cultures, supernatural agents are described as having minds. Contrary to some theological doctrines that cast God as an abstract universal force, Ground of Being, or the totality of everything, God has a remarkably human-like mind in the natural religion of the faithful. God can get angry when His followers do not act in accordance with His desires. Ancestor spirits will be pleased when they receive the proper signals of fealty and allegiance. Zeus has plans for humans that often upset his wife Hera.

Representing the mind of a being that your sense organs don’t perceive may require particularly potent mindreading abilities. Americans, Czechs, and Slovaks with better mindreading abilities are more likely than others to believe in God (Willard et al, 2020 but see Maij et al, 2017). 

Women are more religious than men. Ever wonder why? Well, women are on the average better at mentalizing and empathy. Once we adjust for men’s inferior abilities, women and men don’t differ in their belief in supernatural agents (Norenzayan et al, 2012).

If religiosity relies on mindreading, we might expect damage to its circuitry to affect religiosity. And indeed, autistic individuals are on average much less religious (Norenzayan et al, 2012). 

If religiosity relies on mindreading, we might expect theological reasoning to emerge at the same life stages as ordinary social reasoning. 3yo reasoning falls prey to a reality bias— in verbal reasoning, these children fail to distinguish between the state of reality and peoples’ (sometimes inaccurate) mental states. 4.5yo children become capable of reasoning about the false beliefs of other agents.

Do children intuitively treat supernatural agents as earthly? Lane et al (2010) answers in the affirmative. As children begin to appreciate human beliefs as fallible, they initially attribute similar limitations to all agents, including agents with exceptional powers (in the experiment, God and Mr. Smart). Only later do children learn to overcome their intuitions and affirm depictions of these “super-agents”.

Adults show this same penchant for viewing God as having an essentially human mind. Barrett and Keil (1996) show that even adults, reading a story of God in transcendent terms, think of God as having human-like mental limitations. 

If religiosity relies on mindreading, we might expect thinking about, and praying to, God should activate brain regions associated with mindreading. Indeed, that is precisely what was found in e.g. Schjoedt et al (2009)

Attachment to God

For obvious evolutionary reasons, babies don’t just care about their physical needs, but also the relationship with their caregivers. The attachment system is responsible for promoting these crucial relationships. The Strange Situation task nicely illustrates how it works:

An infant and its caregiver are taken to a room full of toys.  A stranger enters the room, interacting with the caregiver.  The caregiver leaves the room for a few minutes.  Then, after a while, the caregiver returns.  The infant’s behavior is carefully recorded.

How would you anticipate children to respond? It turns out that responses fell into three categories:

  1. Some children did not acknowledge the caregiver, seemingly only interested in play. 23% of all children exhibited this avoidant attachment 
  2. Some children clung to the caregiver, refusing to let go & resume play for some time. 15% of all children exhibited this anxious attachment.
  3. Some children came to hug the caregiver, and then peacefully resumed play. 62% of all children exhibited this secure attachment. 

These attachment styles have been shown to correlate with the emotional availability of the caregivers. A parental style of consistent care promotes security; inconsistent care promotes anxiety; consistent lack of care promotes avoidance. 

The attachment system doesn’t just facilitate parent-child relationships. It is also the substrate of romantic love, and generally friendships of all kinds. Which leads to a question: do believers use their attachment system to relate to God?

Granqvist et al (2010) adduces evidence for the affirmative. Consider this quote from Mother Teresa:

Since age 49 or 50 this terrible sense of loss—this untold darkness—this loneliness, this continual longing for God—which gives me that pain deep down in my heart—Darkness is such that I really do not see . . .—the place of God in my soul is blank—There is no God in me—when the pain of longing is so great—I just long & long for God—and then it is that I feel—He does not want me—He is not there—. . . God does not want me—sometimes I just hear my own heart cry out—“My God” and nothing else comes. 

It seems at least some believers experience relational attachment to gods, ancestors, etc. Just as people seek out other human minds in time of loneliness and stress, these are the times they are uniquely likely to affirm their religious beliefs. 

  1. Many unpredictable negative events (including illness, injury, fatigue, frightening events, and separation from loved ones), activate the attachment system and activate a search for minds. These same situations cause people to turn to God (Gray & Wegner, 2010).
  2. Subtly primed religious concepts buffer religious participants against the negative consequences of laboratory induced social isolation (Aydin et al 2010).  

Supernatural attachment is a bit unusual, however. Generally speaking, egocentrism describes the phenomena of, when we don’t have much knowledge of other people’s views, we often attribute our own values & beliefs onto them. Epley et al (2009) show that this phenomena happens even more frequently for people’s relationships with gods. 

Dualism, Disembodied Minds, and the Afterlife

Mind-body dualism represents the notion that minds and bodies are completely separate substances. Western thinkers often associate dualism with Rene Descartes. But cross-cultural research suggests that adult intuitions about disembodied minds are strikingly similar across societies (Cohen et al., 2011; Roazzi et al, 2013). Recent work has even found dualist thinking in ancient Chinese texts (Slingerland & Chudek, 2011). 

Further, children’s belief in the afterlife (at least in Western cultures) gets weaker with age, not stronger (Bering, 2006). While enculturation often does weaken these intuitions, mind-body dualism re-emerges in adults under cognitive load (Forstmann & Burgme, 2015).

Dualistic intuitions are a human universal. But why? Why should movies about Freaky Friday feel intuitive?

Bloom (2007) posits the independent system hypothesis. On this view, our dualism is a natural by-product of the fact that we have two distinct cognitive systems, one for dealing with material objects, the other for social entities. These systems can operate independently, and have incommensurable outputs. Hence dualism emerges as an evolutionary accident.

  • For example, Kuhlmeier et al (2004) tested 5-month-olds’ ability to reason about the law of continuous motion as it applies to the human body.  For inanimate objects, infant are surprised (i.e., look longer) when the object disappears from behind one barrier and then seems to reemerge from a separate barrier. Not so for humans!  This suggests that babies interpret humans with radically different assumptions, than they do other objects.
  • Indeed, our ability to imagine a disembodied mind often emerges early in childhood. Taylor’s (1999) research on children’s propensity to maintain social relationships with imaginary friends suggests that by age 3 to 4 years, children are already equipped to sustain vivid mental representations of the wants, opinions, actions, and personalities of such an agent. Of course, children do understand their imaginary friends as fictive (not so for adult beliefs about God). 

Most social interactions require physical perception and mindreading processes to execute in parallel. But mindreading supports offline processing; that is, we can think of others not in the room. On the independent systems hypothesis, offline processing makes sense – only one system is operational.

Sigmund Freud once said,

Our own death is indeed unimaginable and whenever we make an attempt to imagine it we can perceive that we really survive as spectators. 

The consensus view of mindreading is that it relies, at least in some ways, on simulation to attribute mental states to others (hence, the egocentric bias). This mechanism is uniquely poorly equipped to contemplate death. In line with this simulation constraint hypothesis, Bering (2006) found that that most undergraduate students, who later claimed to believe that consciousness stops at death), nevertheless stated that the dead person knew he was dead. 

The most dramatic demonstration of dualism concerns the development of afterlife beliefs. Bering and Bjorklund (2004) told children of different ages stories about a mouse that died, and asked about the persistence of certain properties. When asked about biological properties of the mouse, the children appreciated the effects of death, including that the brain no longer worked. But when asked about the psychological properties, most the children said that these would continue – the dead mouse can think thoughts, and hold desires. The body was gone, but the soul survives.

Death is thus processed biologically, and does not terminate social inference systems. This fact will be familiar to the bereaved.

Thus, the afterlife and immaterial agents are innately-endowed intuitions. But these disembodied minds are felt to have all-too-human mental lives. 

Mythology and MCI Theory

Innate dualism is explained by the independent system hypothesis. This in turn relates to the disjoint core knowledge hypothesis: there seem to be distinct ontologies built into the nervous system: objects vs organisms vs minds. Each ontology is associated with a distinct set of modules and the intuitions they generate. Most social interactions engage both biological and psychological modules; intuitions about disembodied minds express themselves when only the latter modules are active.

The disjoint core knowledge hypothesis allows us to better understand mythology. Artifacts of Paleolithic religion contain counterintuitive entities: stuff that blurs ontological boundaries:

Folklore like Grimm’s Fairy Tales are also rife with such counterintuitive entities (e.g., a talking wolf).

Too many counterintuitive entities produces a confusing story. But why have them at all? The simple answer is memorability: intuitive concepts are easy to grasp, but are quickly forgotten; a small number of counterintuitive entities increases the salience (and the memorability!) of the myth.

The disjoint core knowledge hypothesis explains why so many of our myths are seasoned with minimally counterintuitive (MCI) ingredients.

Two Teleological Instincts

American 4- and 5-year-olds differ from adults by finding the question “what’s this for?” appropriate not only to artifacts and body parts, but also to whole living things like lions (“to go in the zoo”) and nonliving phenomena like clouds (“for raining”). Kelemen (2004) shows how, around this age, children adopt a design-based teleological view of objects with increasing consistency. 

This trend seems to be innate rather than cultural. A study of responses young children receive when asking questions about nature indicates parents generally favor causal rather than teleological explanation. (Kelemen et al 2002). While physical explanations are culturally favored, teleological thinking does re-emerge in adults under cognitive load (Kelemen et al, 2009).

This form of object teleology (“what’s it for?”) is theorized to be a byproduct of artifact cognition. Great apes are toolmakers. Part of our ability to understand such artifacts is the capacity to reverse-engineer their purpose: to infer specific goals and motivations of their creators.

In contrast with object teleology, autobiographical teleology (“purpose in life”) ascribes purpose to significant life events. We know that counterfactual reasoning is used to construct a sense of purpose (Kray et al, 2010). The stories we tell ourselves about these events coalesce into our narrative identity during late adolescence, and casts a strong influence on life satisfaction (McAdams & McLean, 2013). There is a correlation between autobiographical teleology and religiosity, but the nature of this relationship is unclear to me. 

Anthropomorphism generate paranormal beliefs

In 1976, NASA’s Viking 1 was orbiting Mars, exploring the surface for possible landing sites. Here’s one of its pictures, in the Cydonia region:

Anthropomorphism, the penchant for hallucinating agents in natural environments, was recognized by David Hume as a pervasive human weakness:

There is an universal tendency among mankind to conceive all beings like themselves, and to transfer to every object, those qualities, with which they are familiarly acquainted, and of which they are intimately conscious. We find human faces in the moon, armies in the clouds; and by a natural propensity, if not corrected by experience and reflection, ascribe malice or goodwill to everything, that hurts or pleases us.

Daniel Dennett has made much of this instinct, dubbing it the hyperactive agency detection device (HADD) module. But Willard et al (2020) found anthropomorphism had zero effect on belief in God. Indeed, they were weakly negatively correlated, presumably because of the Abrahamic faith’s emphasis on aniconism. However, a person’s anthropomorphic bias does predict that individual’s beliefs about the paranormal (ghosts, aliens, etc).

The Four Pillars of Religiosity

Mindreading plays a central role in religious instincts. Its influence is largely mediated by more specific intuitions about mind-body dualism, promiscuous teleology, and anthropomorphism.  The specific relationships between these factors has been mapped:

Dual-process theory posits human cognition can be understood and implicit intuition vs explicit reflection. Since religion is rooted in social intuitions, we might predict that people who rely more extensively on their intuitions are more religious. And that is precisely what we find. 

This post locates the cognitive basis of religion in three mindreading-based intuitions, together with the penchant to take such intuitions at face value. But we will see later, there are at least two other drivers of religiosity. First, religion is promoted by cultural transmission via CRedibility Enhancing Displays (CREDs). Second, religion tend to flourish under conditions of existential insecurity, which is well illustrated by the proverb “there are few atheists in foxholes”.

These four elements promote religious belief. If any of them are missing, weakened or overriden, individuals will tend towards atheism (Norenzayan & Gervais, 2012).

But these factors are not created equal. The size of their contributions have also been extensively researched. While the cognitive factors discussed today inarguably matter, cultural factors have more clout. It is to these factors we will turn next time.

Until then!



  1. Aydin et al (2010). Turning to god in the face of ostracism: Effects of social exclusion on religiousness
  2. Granqvist et al (2010). Religion as Attachment: Normative Processes and Individual Differences
  3. Gray & Wegner (2010). Blaming God for Our Pain: Human Suffering and the Divine Mind


  1. Barrett & Keil (1996). Conceptualizing a Nonnatural Entity: Anthropomorphism in God Concepts
  2. Gervais (2013). Perceiving Minds and Gods: How Mind Perception Enables, Constrains, and Is Triggered by Belief in God
  3. Maij et al (2017). Mentalizing skills do not differentiate believers from non-believers, but credibility enhancing displays do 
  4. Norenzayan et al (2012), Mentalizing deficits constrain belief in a personal God
  5. Schjoedt et al (2009). Highly religious participants recruit areas of social cognition in personal prayer 
  6. Taylor (1999). Imaginary companions and the children who create them
  7. Willard, Norenzayan (2013) Cognitive biases explain religious belief, paranormal belief, and belief in life’s purpose 
  8. Willard et al (2020). Cognitive Biases and Religious Belief: A Path Model Replication in the Czech Republic and Slovakia With a Focus on Anthropomorphism


  1. Bering (2006). The folk psychology of souls 
  2. Bering and Bjorklund (2004) The natural emergence of reasoning about the afterlife as a developmental regularity.
  3. Bloom (2007). Religion is natural. 
  4. Carruthers (2020). How Mindreading Might Mislead Cognitive Science
  5. Cohen et al (2011). Cross-Cultural Similarities and Differences in Person-Body Reasoning: Experimental Evidence From the United Kingdom and Brazilian Amazon 
  6. Forstmann & Burgmer (2015). Adults Are Intuitive Mind-Body Dualists
  7. Kuhlmeier et al (2004). Do 5-month-old infants see humans as material objects? 
  8. Lane et al (2010). Children’s Understanding of Ordinary and Extraordinary Minds. 
  9. Roazzi et al (2013). Mind, Soul and Spirit: Conceptions of Immaterial Identity in Different Cultures 
  10. Slingerland & Chudek (2011). The Prevalence of Mind–Body Dualism in Early China 

MCI Theory

  1. Norenzayan et al (2006). Memory and Mystery: The Cultural Selection of Minimally Counterintuitive Narratives
  2. Lindeman et al (2015). Ontological confusions but not mentalizing abilities predict religious belief, paranormal belief, and belief in supernatural purpose


  1. Kelemen et al (2002). Why things happen: teleological explanation in parent-child conversations. 
  2. Kelemen (2004). Are Children ‘‘Intuitive Theists’’? Reasoning About Purpose and Design in Nature 
  3. Kelemen et al (2009) The human function compunction: Teleological explanation in adults. 
  4. Kray et al (2010). From what might have been to what must have been: Counterfactual thinking creates meaning.
  5. McAdams & McLean (2013). Narrative Identity.


  1. Norenzayan & Gervais (2012). The origins of religious disbelief
  2. Epley et al (2009). Believers’ estimates of God’s beliefs are more egocentric than estimates of other people’s beliefs 
  3. Riekki et al (2013). Conceptions about the mind-body problem and their relations to afterlife beliefs, paranormal beliefs, religiosity, and ontological confusions

Kinship explains the I/C Dimension

Part Of: Culture sequence
Followup To: Individualism vs Collectivism
Content Summary: 3000 words, 30 min read

Forager vs Farmer

Homo erectus was a forager. We know this from the fossils: our anatomy diverged from the apes precisely for those features that most support running/hunting (including longer legs, foot arch, fat gluteus maximus, etc). Our species began hunting & gathering some 1,800,000 years ago.

9,000 years ago we switched to farming. Why then? Climate measurements from ice cores shed light on the answer. During the Pleistocene, the climate was extremely variable, with dramatic ecological shifts about every century. In fact, several periods of intense change have been linked to speciation events within the hominin line. 

But the same Milankovitch cycles later introduced periods of climate stability: 12-11 kya, and 9-0 kya. The first stable period correlates with our species first attempt at proto-farming: the Natufian period. Variability returned for another two millennia until the Neolithic revolution led to the true advent of agriculture. 

Why farm? The less nutritious diets of farmers left them shorter, sicker, and more likely to die young. The surplus also generated tremendous inequality, which induced severe warfare between farming communities, whose impact is visible today in the Y-chromosome. 

But farmers did reproduce more quickly than hunter-gatherers. With the “right” set of institutions, farmers could spread across the landscape like an epidemic, driving out foragers in their path. Early farming spread not because it was a better lifestyle, but because farming communities with particular institutions beat mobile hunter-gatherer populations in intergroup competition

Tight vs Loose Kinship

Ever since the Neolithic Revolution, human beings were given in marriage to their cousins & in-laws. The small cost of genetic disorders was more than compensated by social benefits of marriage alliances, creating a “Goldilocks Zone” of optimal mates at intermediate levels of relatedness (second cousins).

These tight (intensive) kinship systems emphasize relatedness-increasing social norms of kin marriages, polygyny, endogamy, and lineal fissions because these behaviors create strongly overlapping networks of kin that often co-reside in the same community. Intensive systems often include marriage alliances between lineages leading to cross-cousin marriages and converging networks of kin (Levi-Strauss, 1949).

In contrast, loose (extensive) kinship lacks most, if not all, of the above relatedness-increasing social norms (Yellen and Harpending, 1972). Marrying unrelated or distantly related individuals increases the total possible numbers of kin by inclusion of a wider cast of individuals to form a more diverse kinship network.  Extensive kinship systems include more geographically-distant marriages in other communities (Fix, 1999) to form alliances with a large number of affines in a diffuse kinship network (Bugos, 1985). 

In contrast to agricultural societies, foraging societies tend to employ loose kinship:

Kinship systems are solutions to economic problems. Loose kinship is useful in unpredictable environments and for nomadic populations given that it provides a plethora of residential options. Hunter-gatherers that exploit a diversity of unevenly distributed food resources may need to hedge their bets by having kin in different places in times of need (Yellen and Harpending, 1972). In contrast, tight kinship reduces the dilution of inheritable family wealth, and may help with kin-based resource defense of such wealth, which is more important for many agropastoral societies as opposed to hunter-gatherer societies (Borgerhoff Mulder et al., 2009). 

Correlates of these kinship systems can be summarized as follows:

Clans and Patriarchy

All pre-modern agricultural societies exhibited tight kinship. To motivate this claim, I want to explain the process by which states evolved.

In all societies, genealogy is the same. But genealogical concepts differ, drawing attention to certain aspects of your family tree, while eliding others. Societies either trace lineages through one parent (unilineal) or both (bilineal). Agriculturalists overwhelmingly use unilineal descent. Why? 

  • This agricultural lifestyle requires sedentism, which fosters community stability. This in turn promotes more elaborate kinship structures, and unilocality. 
  • The agricultural surplus incentivizes resource competition (warfare). In warfare, it is advantageous to construct raiding coalitions with few conflicts of interest. In unilineal systems, every person belongs to just one kinship group. 

There are two forms of unilineal descent: through the mother (matrilineal) or the father (patrilineal). Patrilineal inheritance is reflected in e.g., traditional European practices of the wife taking on the husband’s last name. 

Of these two options, patrilineal social systems are by far the most common. Many explanations for matrilineality have been proposed; one recent proposal suggests they helped building cross-cutting male sodalities for external warfare across meta-ethnic frontiers (Jones 2010). In contrast, Ember et al (1974) found that internal warfare helps predict patrilineality (easier to defend property when all sons live under the same roof) and contiguous lineages (best to keep extended family nearby to help).

Patrilineal social systems are known as clans

Incest aversion is an innate biological response to avoid genetic abnormalities. Known as the Westermarck effect, it is a form of reverse sexual imprinting. In contrast, incest taboos are human-specific norms instilled by culture, which extend the range of incest aversion.  Nearly all clans incest taboos typically forbid within-clan marriage, for at least two reasons. This suppresses sexual competition among men of the same clan and instead focuses their mating efforts outward, on nearby clans. Such exogamy also builds alliances with other clans. (Walter 2000).

Arranged marriages empower patriarchs to strategically use their daughter’s marriages to nourish their clan’s network of alliances. These alliances are reinforced by norms such as levirate marriage (e.g., Deut 25:5-10), which specify that when the husband dies, his surviving wife must marry one of his brothers. This sustains the marital alliance between clans. 

Agriculture won, clans won, consanguineous marriage won. This is why all major world religions (with the exception of the Roman Catholic Church, for reasons we’ll explore next time) are permissive of these intensive kinship strategies including cousin marriage (and, in the Hebrew Bible, also affinal and uncle-niece marriages).

Scaling Up: The Evolution of Statecraft

Agricultural groups compete for resources (surplus). Since group size is a critical determinant of success in intergroup competition, this placed tremendous pressure on groups to scale up. But scaling up is hard. But in the Sepik region of New Guinea, anthropologists have long noted that villages rarely exceeded 300 individuals (3-5 clans, each of which usually consist of several related lineages). If a village strove to grow much larger than this, fissions would erupt, and the village would split – typically along clan lines. Within-clan cooperation is typically not too difficult (aided by the evolutionary logic of Hamilton’s rule). 

However, the relentless logic of cultural group evolution did eventually find two ways to scale up. 

First, age-sets use rituals to better integrate clans. Psychologically potent initiation rituals (rites of terror; roughly, “hazing on steroids”) forge deep bonds between cohorts of males from different kin-groups. The phenomenology of these rituals is paralleled by comradery experienced by the military (band of brothers). After an initiation, norms specify that this cohort is endowed with a new set of privileges, responsibilities, and obligations. Age-sets often work, play and feast together as a unit. Failure to meet their cohort’s collective obligations could threaten to delay their next ritual promotion; which could preclude the entire group from marriage etc etc. 

Second, segmented lineages use lineage myths to bind clans. Norms demand that more closely related clans, who usually control adjacent territories, ally themselves against more distantly related segments. If there is a conflict between brothers, it will be settled by all the brothers, and cousins will not take sides. If the conflict is between cousins, brothers on one side will align against brothers on the other side. However, if the conflict is between a member of a tribe and a non-member, the entire tribe, including distant cousins, could mobilise against the outsider and his or her allies. That tiered mobilisation is traditionally expressed, for example, in the Bedouin saying:

Me and my brothers against my cousins, me and my cousins against the world.

I’ll let Henrich (2020) describe the implications:

This descent-based institution is built around personal and corporate honor. A man’s safety, security, and status—and his family’s—are linked to his reputation. Acts of dishonor can dissolve the reputational shield that protects his property and family from thieves or avengers, and they can reduce his children’s marital prospects and affect the reputation of his entire clan. Hence, relatives closely monitor one another (out of self-interest) and will punish each other in order to restore the honor of their family or clan. Supporting one’s lineage allies is central to each man’s honor. One unfortunate consequence of this is that any particularly aggressive clan could drag the entire maximal lineage into an enduring conflict

Even today, in a world dominated by territorial states, the impact of segmentary lineages can still be felt. In 21st-century Africa, tribal populations with segmentary lineages still experience significantly higher violence and civil war than populations without these institutions. Many familiar cases of chronic conflict in Africa are associated with populations organized by segmentary lineages; for example the two century-long civil war between Dinka and Nuer.  On the other side of the world, the echoes of the culture of honor that were part of Scotland’s segmentary lineages still affect life and death: in counties of the U.S. South, the higher the percentage of Scottish or Scotch-Irish residents in the first U.S. census in 1790, the higher the murder rate is today. The cultural descendants of these migrants still tend to respond aggressively by the honor psychology fermented in segmentary lineages. Boko Haram, Al Shabab, and Al Qaeda, for example, all recruit heavily from populations with segmentary lineages.

Age-sets and segmented lineages allow groups to scale from ~300 to ~3,000; but their success is constrained because they lacked stable, hierarchical authorities. 

Chiefdoms are formed when one clan gains ascendency over sister clans. In the egalitarian multi-clan groups described above, each clan is typically in charge of conducting certain rituals. Ritual ownership often corresponded to real power; e.g. a clan can forbid others from ritual fishing rights. Right to perform these rituals are often grounded in claims about ancestral gods. They can be challenged. Ritual takeovers are one way clans compete within a multi-clan system; given the lack of written language, changes become normalized within a few generations; and then the process may begin anew. In this way, certain clans can emerge as clearly dominant. It is not so much the chief that rules, as the clan (from whose ranks chiefs are elected). 

Recall that arranged marriages serve as an incredibly important social glue; the resultant alliances served to bind clans together and prevent fission. Stratified chiefdoms didn’t emerge until the upper strata (dominant clan) stopped intermarrying with the lower strata. This isolated the upper strata and allowed them to claim that they were fundamentally different from the lower strata—truly divine, superior, and deserving. 

Stratified chiefdoms can evolve into premodern states (kingdoms) as the dominant clan injects new bureaucracies between themselves and the lower strata. These institutions collect taxes, conduct long-distance trade, orchestrate public rites, and marshal armies. They also adjudicate disputes between clans; but premodern states usually left it to the clans to police their own internal affairs, including theft, assault, and even murder. 

Intergroup competition selects for social institutions that scale up. Its relentless Darwinian logic caused societies to scale from 300-person villages to (in the case of the Achaemenid Empire), some 30 million people. But once competition wanes, which often happens when states eliminate their competition, things slowly fall apart. Without the looming threats posed by competing societies, the competition among ruling families within a society will intensify and gradually tear the state-level institutions apart. 

Here, then, is how states evolved from clans:

From Henrich (2020):

At the dawn of agriculture, all societies were built on institutions rooted in family ties, ritual bonds, and enduring interpersonal relationships. New institutional forms were always built on these ancient foundations by variously augmenting, extending, or reinforcing the inherited forms. Social norms related to family, marriage, ritual, and interpersonal relationships became more complex and intensive as societies began to scale up. Crucially, these institutions were always built atop a deep foundation of tight kinship. The fact that people couldn’t simply wipe away their ancient kin-based institutions when building institutions creates what researchers call a strong path-dependence. That is, given that new forms always build on older forms, and these older forms are anchored in our evolved primate psychology, there are a limited number of pathways along which these new institutions can develop. 

Individualism 2.0

Agriculture wins, so we would expect the entire world to employ tight kinship systems. Right?

From 9,000 to 1,000 years ago, this map would indeed have been bright red. However, loose kinship recently made a resurgence in Western (European or European-descended) societies. We’ll explore why this happened next time. 

The civilized world is no longer exclusively dominated by tight kinship. Premodern kin-based states compete with modern impersonal states. 

Kinship Drives the I/C dimension

Last time, we learned about individualism vs collectivism, i.e. the I/C dimension. We adduced lots of data suggesting that cognitive style, social orientation, and moral posture co-vary based on how relationally mobile a society is. 

But why? Why are there systematic differences in relational mobility across nations? To answer this, we turn to our conception of tight vs loose kinship. If you are a male growing up in a clan (with intensive kinship norms), you and your wife will live your entire live in your father’s house. You will be rely on your kin-group for affiliation, for sustenance, for defense. You will not choose your friends or your spouse. In clans, relational rigidity is the norm. We should thus expect tight kinship societies to score highly in the myriad dimensions that comprise the I/C dimension. 

And so it is. Cousin marriage, and the kinship intensity index, are enormously predictive of a holistic cognition, and other-oriented sociality.

You can see how kinship impacts moral systems directly, when investigating rates of blood donations. Tight kinship societies don’t donate blood donations nearly as frequently: why care for strangers (people estranged from your social world) when you can instead invest in the relationships you will keep your entire life? Similarly, they are more likely to trust their in-group than impersonal financial institutions like banks; cousin marriage is enormously predictive of desire to not use checks.

We previously saw how individualistic societies have a dispositional psychology, which features intent as a morally relevant factor. Curtin et al (2020) has shown that kinship intensity explains much of this variance. For low intent scenarios (blue line), looser kinship (moving left) reduced judgment severity.

More generally, and across a suite of features, Schultz et al (2019) show that consanguinity rates explain a dramatic proportion of moral variance, both within-country as seen above, but also between countries. 

In sum, kinship is a very strong determinant of relational mobility, and hence explains most cross-cultural variance along the I/C dimension.

The Role of Pathogens

You may be wondering why sanctity intuitions rely so heavily on disgust, rather than other self-perceptions like dizziness. 

As noted by Schaller & Park (2011), the immune system is a necessary but insufficient protection against disease. The visceral immune system is energetically costly (a 13% increase in metabolic expenditure is required to increase human body temperature by just 1 C), and temporarily debilitating (the syndrome is known as sickness behavior). Surely in addition to a reactive system, animals co-evolved proactive defences against disease: a behavioral immune system.

Disgust evolved to promote pathogen avoidance, and thus contributes to the behavioral immune system. But sometimes people represent contagion risk, even if they aren’t manifesting signs of disease. This is especially true for unfamiliar people, travelling from distant groups with different immunological memory. Is xenophobia related to the behavioral immune system?

The answer appears to be yes. When primed to think about disease, people became much less tolerant of immigration from culturally-dissimilar countries (e.g., in US, immigrants from majority-Muslim countries). 

But the role of diseases extends beyond facultative dispositions. Consistent exposure to disease has been shown in Enke (2019) to increase kinship tightness in societies, along with its characteristic collectivism & ethnocentrism.

Thus, tight kinship is not only an economic response to resource defense, as we saw with agricultural surplus. It also serves to reduce disease transmission. 

The Role of Rice Paddies

We have already discussed how agriculture tends to produce surplus, defense of which strongly incentivizes clan formation. But the specific kind of agriculture matters too! Wheat farming can be conducted by single families on small plots of land. Rice paddy farming, however, due to the economic characteristics of that crop, require multiple families to correlate. This particular cereal, due to the social structures necessary to farm it, induces an even stronger nudge towards allocentric psychology than wheat.

Together with the discussion of pathogens, we have shown evidence to suggest that ecological and economic factors are important antecedents to kinship structure. Ecology doesn’t determine kinship, but it does bias it.


We have seen human societies tend to organize themself using tight or loose kinship. Each kinship system creates its own social worlds, which in turn incentivizes its own suite of psychological adaptations (cognitive, social, and moral). 

One of the virtues of this anthropological theory is that it explains the individualism/collectivism dimension as a function of kinship, and explains why so many moral, social, and cognitive factors covary along this single continuum. 


  1. Barrett et al (2016). Small scale societies exhibit fundamental variation in the role of intentions in moral judgment.
  2. Borgerhoff Mulder et al. (2009). Intergenerational Wealth Transmission and the Dynamics of Inequality in Small-Scale Societies
  3. Bowles & Choi (2013). Coevolution of farming and private property during the early Holocene
  4. Bugos (1985). An evolutionary ecological analysis of the social organization of the Ayoreo of the Northern Gran Chaco
  5. Curtin et al (2020). Kinship intensity and the use of mental states in moral judgment across societies
  6. Dohmen et al (2018). Patience and comparative development.
  7. Ember et al (2014). On the Development of Unilineal Descent
  8. Enke (2019). Kinship, Cooperation, and the Evolution of Moral Systems. 
  9. Fix & Shepherd (1999). Migration and colonization in human microevolution.
  10. Helgason et al (2008). An Association Between the Kinship and Fertility of Human Couples
  11. Henrich (2020). The WEIRDest people in the world: how the West became psychologically peculiar and particularly prosperous
  12. Levi-Strauss (1949). The elementary structures of kinship. 
  13. Jones (2011). The Matrilocal Tribe: An Organization of Demic Expansion
  14. Korotayev (2004) Unilocal Residence and Unilineal Descent: A Reconsideration
  15. Schaller & Park (2011). The Behavioral Immune System (and Why It Matters)
  16. Talhelm et al (2014). Large-Scale Psychological Differences Within China Explained by Rice Versus Wheat Agriculture
  17. Walker & Bailey (2014). Marrying Kin in Small-Scale Societies 
  18. Walter (2000). From Westermarck’s Effect to Fox’s Law: paradox and principle in the relationship between incest taboos and exogamy.
  19. Yellen and Harpending (1972). Hunter‐gatherer populations and archaeological inference

Individualism vs Collectivism

Part Of: Culture sequence
Content Summary: 3000 words, 30 min read

Relational Mobility vs Fixedness

Since the Neolithic Revolution, the vast majority of human beings have spent their days as subsistence farmers. These people do not have many choices about joining groups, or even who they marry. One is more or less stuck with one’s extended family and a few friends. If a farmer’s relationship with these people fails, there is no recourse. Reinventing yourself is not an option; relational fixedness is your reality.  Henrich (2020) describes the social worlds that emerge:

Throughout most of human history, people grew up enmeshed in dense family networks that knitted together distant cousins and in-laws. In these regulated-relational worlds, people’s survival, identity, security, marriages, and success depended on the health and prosperity of kin-based networks, which often formed discrete institutions known as clans, lineages, houses, or tribes.

Within these enduring networks, everyone is endowed with an extensive array of inherited obligations, responsibilities, and privileges in relation to others in a dense social web. The social norms that govern these relationships constrain people from shopping widely for new friends, business partners, or spouses. Instead, they channel people’s investments into a distinct and largely inherited in-group. Many kin-based institutions not only influence inheritance and the residence of newly married couples, they also create communal ownership of property (e.g., land is owned by the clan) and shared liability for criminal acts among members (e.g., fathers can be imprisoned for their sons’ crimes).

In contrast, some modern societies allow people to leave toxic relationships and groups, and join others. The new calculus involves not only “how do I gain status”, but also “where should I gain status”. 

Relational mobility is well illustrated by the WaitButWhy concept of the relationship mountain; whose underlying advice is a form of relationship economics: prioritize friendships with advantageous cost/benefit ratios. 

But, only individualistic people approach relationships in this way. In contrast, allocentric people have steeper mountains (acquaintances are strangers), and less control on who inhabits its slopes. This contrast also applies at more granular levels of detail. Majority-idiocentric societies are individualistic, and societies with mostly allocentric psychologies are collectivist

Your social environment plays a tremendous role in shaping your psychological development. Children enculturated in a relationally mobile context learn to listen to “their inner voice”, to be analytic, and adopt a universal morality. Children in relationally fixed worlds, in contrast, pay much more attention to the quality of these relationships, and their cognitive style and moral posture reflect the primacy of their in-group. 

Two Social Orientations

In Granite In Every Soul, I sketched an important distinction between social identity versus self-concept

Back then I wrote, “Social change causes dramatic fluctuations within your social identity, but decision making requires consistency. Your brain can resolve this tension by relying more heavily on self-concept.” 

We can prove this! When given the prompt “I am…”, socially static people answer in the language of social identity: a father, a husband, etc. But Western, Educated, Individualistic, Rich, Democratic (WEIRD) nations answer in a language of personal attributes: kind, a hard worker, etc. 

Another example. In traditional parts of Indonesia, people do not use personal names, but rather they use teknonyms (the equivalent of “the second son of the Smith family”). In other words, the person is not treated as an autonomous individual but an appendage of the group, in this case the family.

Success in a socially rigid world means conforming to group opinion. The Japanese proverb, “the nail that stands out gets pounded down” contrasts with the individualist proverb to “be yourself”. Indeed, as measured by the Asch conformity test (answering “how long is this line?” when confederates give the obviously-incorrect answer), collectivist cultures are more likely to conform to the group.

More generally, WEIRD nations express the syndrome described by Hofstede (2003) as the individualism syndrome. You think it’s normal to emphasize autonomy and “individual rights” above harmony? Normal to prioritize individual achievement over one’s group? Normal to leave a group if you do not enjoy being a member? 

All of these national measurements co-vary: if people in your culture uses the language of relationship to describe itself, it will very often conform more too. Hofstede (2003) takes advantage of this fact to summarize all of the above measurements into a single individualism score. 

Two Cognitive Patterns

Some cognitive content is fixed, or culturally invariant. Naive theories of mechanics and physics (e.g., Aristotelian physics), naive theories of biology (e.g., essentialism), and naive theory of mind (e.g., dualism) appear so early and are so widespread that it seems quite likely that at least some aspects of them are largely innate and resistant to social modification. 

But culture does exert an influence on many other cognitive traits. Given that human beings are social animals, is it really so surprising our social worlds are projected onto our habits of thought?

People immersed in a socially static world rely on social identities, which is heavily sensitive to the norms imbued within a situation. They tend to express a tacit version of situationist psychology: the situation dictates behavior. In contrast, socially dynamic worlds incentivize the use of self-concept, where you ascribe attributes to yourself. Individualists use a dispositional framework, with significant downstream effects. 

The fundamental attribution error, the tendency to explain behavior excessively by someone’s intrinsic attributes rather than by the situation involved, was originally suspected to be a human universal. But it turns out that this bias is not present in collectivist cultures (Norenzayan et al. 2002). You are much less prone to make this mistake if you lack a robust concept of personality. 

In collectivist culture, with its emphasis on multifaceted social identity, social behavior tends to be more relationship-specific. In individualist cultures, these very same behaviors are typically condemned as hypocritical and contradictory. Indeed, cognitive dissonance (an aversion to discovering contradiction within yourself) is not a human universal; rather, it is primarily expressed in individualist cultures. This tolerance for relationship-specificity/contradiction is is nicely illustrated by this Triandis vignette: “I had a friend from India who told me he was a meat-eating vegetarian. When I asked him how could this be, he replied ‘well, I am a vegetarian, but when other people are eating meat, I do too.’”

When idiocentrics see social contradiction, they debate to see who is right. In contrast, allocentrics try to find elements of truth in opposing positions (a dialectical approach). This Middle Way also serves to promote harmony, and preclude relationship collapse.

Confusingly, individualism & collectivism are also associated with non-social effects. Consider the triad categorization task, where you are asked whether a glove is more related to a scarf, or a hand. Individualist countries resonate to the former (using the analytical concept of CLOTHING); collectivist ones resonate with the latter (using affordance relations; what is done with the glove). This proclivity for parsing the world in terms of objects versus relations must explain why language learners in collectivist nations tend to learn verbs more quickly than nouns, and vice versa.

Allocentric people spend lots of time with the same individuals. Familiarity breeds communicative efficiency: you can say more with fewer words. Thus, collectivist cultures typically feature high-context communication. An example from Triandis (1994)

For example, in Indonesia, a lower-class man and an upper-class woman met secretly and got to the point where they wanted to marry. They informed their parents, and following protocol the man’s mother visited the woman’s mother. The latter served her tea and bananas. Since tea is never served with bananas, that was a “dissonant” stimulus that said “no,” without actually saying the word. Both women saved face. 

In contrast to high-context cultures, we see low-context cultures which pay much less attention to nonverbal cues. Since many more interactions are unfamiliar, everything is spelled out more explicitly.

Surprisingly, this social emphasis on context manifests as differences in extremely low-level perceptual processes. For example, in the rod and frame test, people are asked to vertically align a rod, pictured within a rectangular frame. Idiocentric, object-centric people perform noticeably better than context-aware allocentrics; this phenomenon is known as field dependence. Ji et al (2000) also show how allocentrics are also much better at detecting covariation when different objects of a picture are simultaneously distorted. 

San Martin et al (2019) show that relational mobility predicts these cognitive patterns. Taken together, the I/C dimension is associated with two distinct cognitive patterns: analytic versus holistic cognition.

Why Nonsocial Differences? The Locus of Control Hypothesis

It’s fairly easy to trace a link from relational mobility to differences in social orientation and moral posture. But what possible relationship could there be between relational mobility and field dependence?

Is the relationship coincidence? We might hypothesize linguistic, genetic, history of thought, or other unrelated cultural forces drive the analytic vs holistic continuum.  

But, per Varnum et al (2010), two streams of evidence suggest the answer is “no”. First, social orientation and cognitive style don’t just co-vary between the United States and East Asia. Covariation has also been found e.g., between European nations. The phenomena also covary within countries, such as Hokkaido Japanese vs Mainland Japan, US working-class vs middle class, Orthodox vs secular Jews. Second, when you prime a subject with social orientation, the corresponding cognitive style is expressed. 

So the social ecology we inherit from our parents shapes our cognitive style. But why?

One suggestion is the locus of control hypothesis. It turns out that desire for personal control is lower among East Asians than among Westerners. When Zhou et al (2012) experimentally induced desire for control (via deprivation), allocentrics start to think more analytically!

They also found that control deprivation made East Asians …

  1. … shift toward favoring logical arguments rather than dialectical ones.
  2. … categorize by rules rather than relations/similarities.
  3. … more open to and more convinced by arguments that were logically sound but employed unintuitive exemplars.
  4. … predict the future more by linear extrapolation extending current trends rather than by expecting reversals toward holistically balanced opposites.

San Martin et al (2019) show that locus of control statistically mediates the relationship between relational mobility and analytic cognition. Loss of control also stimulates approach motivation (Greenway et al 2013). Approach motivation is more frequently used by idiocentrics (Elliot et al 2001). Approach motivational processes are predominantly left-lateralized (Jonas et al 2014). This may explain why idiocentric psychology relies so heavily on the left hemisphere, and vice versa for allocentrics (Rozin et al 2016).

I have not yet found an explanation for why this cluster of mechanisms explain the features of analytic cognition (what does control have to do with field dependence?) But a complete account of control, power, and approach vs avoidance might be able to establish a more complete picture. In the meantime, I will content myself with the knowledge that the mediation of these cognition effects is at least partially identifiable.

Two Moral Systems

Consider the Passenger’s Dilemma:

You are riding in a car driven by a close friend. He hits a pedestrian. You know that he was going at least 35 mph in a speed zone of 20 mph. There are no witnesses, except for you. His lawyer says that if you testify under oath that he was driving only 20 mph, it may save him from serious legal consequences. Do you think 1) that your friend has a right to expect you (as his close friend) to testify that he was going 20mph; or 2) that your friend has no right to expect false testimony. 

In a socially rigid world, the “right thing to do” is to lie for your friend. In a socially mobile world, the “right thing to do” is to act on universal principles. Individualistic nations are much more likely to not use false testimony.

Jonathan Haidt’s Moral Foundation Theory acknowledges a bifurcation between impersonal vs interpersonal moralities. To quote Haidt (2012)

The ethic of autonomy is based on the idea that people are, first and foremost, autonomous individuals with wants, needs, and preferences. People should be free to satisfy these wants, needs, and preferences as they see fit, and so societies develop moral concepts such as rights, liberty, and justice, which allow people to coexist peacefully without interfering too much in each other’s projects. This is the dominant ethic in individualistic societies. You find it in the writings of utilitarians such as John Stuart Mill and Peter Singer (who value justice and rights only to the extent that they increase human welfare), and you find it in the writings of deontologists such as Kant and Kohlberg (who prize justice and rights even in cases where doing so may reduce overall welfare).

But as soon as you step outside of Western secular society, you hear people talking in two additional moral languages. The ethic of community is based on the idea that people are, first and foremost, members of larger entities such as families, teams, armies, companies, tribes, and nations. These larger entities are more than the sum of the people who compose them; they are real, they matter, and they must be protected. People have an obligation to play their assigned roles in these entities. Many societies therefore develop moral concepts such as duty, hierarchy, respect, reputation, and patriotism. In such societies, the Western insistence that people should design their own lives and pursue their own goals seems selfish and dangerous— a sure way to weaken the social fabric and destroy the institutions and collective entities upon which everyone depends.

The ethic of divinity is based on the idea that people are, first and foremost, temporary vessels within which a divine soul has been implanted. People are not just animals with an extra serving of consciousness; they are children of God and should behave accordingly. The body is a temple, not a playground. Even if it does no harm and violates nobody’s rights when a man has sex with a chicken carcass, he still shouldn’t do it because it degrades him, dishonors his creator, and violates the sacred order of the universe. Many societies therefore develop moral concepts such as sanctity and sin, purity and pollution, elevation and degradation. In such societies, the personal liberty of secular Western nations looks like libertinism, hedonism, and a celebration of humanity’s baser instincts

Indeed, Enke (2019) shows that individualist nations score higher in the universal moral sentiments (Harm & Fairness); whereas collectivist nations score more highly in parochial moral sentiments (Loyalty, Authority, and Sanctity). 

Let’s turn to the moral relevance of intention. All people possess the mindreading faculty, which generates guesses about the intentions of others. Because idiocentric people more strongly believe in personality, they are more likely to use these inferences while judging the actions of others. When asked to judge the badness of accidental versus intentional theft, WEIRD countries are much more likely to evaluate the cases separately.

Relational mobility permits leaving behind damaged reputations, making reputations in individualistic societies a less reliable source of information. Ironically, trust and norm internalization may be most vital in individualistic environments (Sosis 2005). 

Finally, idiocentric people are much more likely to experience guilt (an internal motivation), rather than shame (an external-relational emotion).

Moral systems are not human universal. There are two moralities, not one. Relational mobility determines which morality you internalized as a child.

Residential Mobility

A questionnaire from Lun et al (2012) asked participants who they liked more:

  1. the egalitarian who splits her time between helping the friend and the stranger
  2. the loyal friend, who only helped her friend

One of your potential partners always preferred the egalitarian helper. The other always liked the loyal friend. Who do you want to work with? 

Did your family move residences while you were a child?

If you haven’t, there’s a 90% chance you prefer the non-egalitarian friend. If you moved once as a child, the percentage dropped to 75 percent. If you move more than once, the percentage drops to 62 percent.

Experiments like this show that residential moves, and their concomitant need for new relationships, activates the idiocentric syndrome, including impersonal prosociality.  strengthen people’s preferences for egalitarianism and improve how they treat strangers. These experiences strengthen egalitarian intuitions, flatten the in-group vs out-group distinction, and shift people away from relying too heavily on their long-enduring social networks. 

The same effect can be produced experimentally. Subconscious primes of residential mobility increase people’s motivations to expand their social networks—to establish and nourish new relationships. 

Residential mobility produces relational mobility. Thus, it is not surprising that moving promotes idiocentrism.


When you encounter a culture truly different from your own, it is easy and natural to feel a sense of wonder and amazement.

There is a tendency to associate that reverence with a belief that every culture is unique, like a snowflake. But that conclusion need not follow.

To build a theory of cultural difference, it helps to remember concepts from dimensionality reduction algorithms like PCA. There are thousands of differences across cultures, true; but it is possible to identity which phenomena vary together.

The individualism/collectivism continuum, or I/C dimension was one of the first dimensions discovered by Hofstoede, while mining through survey data from IBM offices across the continents. In all the voluminous research outlined above, it is worth noting that the mean differences are often very large, typically on the order of 2:1, 3:1 or higher (Nisbett et al 2001). This is why the I/C dimension is held to be the most significant dimension of human cultural variation (Triandis 1994).

Recall the I/C dimension explains why cognitive, social and moral differences covary, and are largely explained by a single factor: relational mobility.

A couple reminders here:

  • The I/C dimension is a continuous, not a binary, variable.
  • The I/C dimension, while originally studied as East Asia vs United States, manifests in all nations, and within all nations.

Is the I/C dimension the only significant driver of global psychological variation? By no means! Cross-cultural psychology has revealed (at least) three other dimensions that explain much cultural variation: 

Until next time.


  1. Bond & Smith (1996). Culture and Conformity: A Meta-Analysis using Asch’s (1952b, 1956) 
  2. Elliot et al (2001). A Cross-Cultural Analysis of Avoidance (Relative to Approach) Personal Goals.
  3. Enke (2017). Kinship Systems, Cooperation and the Evolution of Culture
  4. Greenway et al (2015). Loss of control stimulates approach motivation.
  5. Haidt (2012). The Righteous Mind: why good people are divided by politics and religion
  6. Hofstede, G. (1980). Culture’s consequences: International differences in work-related values
  7. Hsu et al (2012). Critical Tests of Multiple Theories of Cultures’ Consequences 
  8. Inglehart & Baker (2000). Modernization, cultural change, and the persistence of traditional values
  9. Jonas et al (2014). Threat and Defense: From Anxiety to Approach
  10. Lun et al (2012). Residential mobility moderates preferences for egalitarian versus loyal helpers
  11. Ji et al (2000). Culture, Control, and Perception of Relationships in the Environment 
  12. Ma & Schoeneman (1997). Individualism vs Collectivism: a comparison of Kenyan and American self-concepts
  13. Marcus & Kitayama (1991). Culture and the Self: Implications for Cognition, Emotion, and Motivation 
  14. Nisbett et al (2001). Culture and systems of thought: holistic versus analytic cognition.
  15. Norenzayan & Nisbett (2000). Culture and Causal Cognition
  16. Rozin et al (2016). Right: Left:: East: West. Evidence that individuals from East Asian and South Asian cultures emphasize right hemisphere functions in comparison to Euro-American cultures
  17. San Martin et al (2019). Relational Mobility and Cultural Differences in Analytic and Holistic Thinking
  18. Schwartz, S. H. (2006). A theory of cultural value orientations: Explication and applications
  19. Sosis (2005). Does Religion Promote Trust? The Role of Signaling, Reputation, and Punishment
  20. Steenkamp (2001). The role of national culture in international marketing research.
  21. Triandis (1994). Culture and social behavior.
  22. Trompenaars & Hampden-Turner (1998). Riding the waves of culture: Understanding diversity in global business.
  23. Varnum et al (2010). The Origin of Cultural Differences in Cognition: Evidence for the Social Orientation Hypothesis
  24. Zhou et al (2011). Control Deprivation and Styles of Thinking