[Excerpt] The Sphex Within You

Excerpt From: Keith Stanovitch, Robot’s Rebellion
Content Summary: 400 words, 2 min read

Consider the behavior of the digger wasp, Sphex ichneumoneus.  The female Sphex does a host of amazing things in preparation for her eggs.  

  1. After digging a burrow, she flies off looking for a cricket.
  2. When she finds one, she stings it in a way that paralyzes it but does not kill it.  
  3. She brings it back to the burrow and sets it just outside at the threshold
  4. Then she goes inside to make sure things are safe inside the burrow.  
  5. If they are, she then goes back outside and drags in the paralyzed cricket.  
  6. She then lays her eggs inside the burrow, seals it up, and flies away.  When the eggs hatch, the wasp grubs feed off the paralyzed cricket which has not decayed because it was paralyzed rather than killed.

All of this seems to be a rather complex and impressive performance put on by the Sphex – a real exercise of animal intelligence.  It seems so, that is, until we learn that virtually every step of the wasp’s behavior was choreographed by rigid and inflexible preprogrammed responses to specific stimuli in the Sphex environment.

Consider, for example, the wasp’s pattern of putting the paralyzed cricket on the threshold of the burrow, checking the burrow, and then dragging the cricket inside.  Scientists have uncovered the rigidity of these behaviors by moving the cricket a few inches away from the threshold while the wasp is inside checking the burrow.  When she comes out, the wasp will not now drag the cricket in.  Instead, she will take the cricket to the threshold and go in again to check the burrow.  If the cricket is again moved an inch or so away from the threshold, the Sphex will again not drag the cricket inside, but will once more drag it to the threshold and for the third time go in to inspect the burrow.  Indeed, in one experiment where the investigators persisted, the wasp checked the burrow forty times and still not drag the cricket straight in.  These fixed action patterns dictated a certain sequence of behaviors triggered by a particular set of stimuli, and any deviation from this was not tolerated.

Ethologists often feel unnerved while observing insects and other lower animals: all that bustling activity, but there’s nobody home!

Let’s call this unnerving property sphexishness.  These simple, rigid routines that underpin the complexity of the surface behavior of simple creatures spawns in us a worrying thought:

What makes you sure you’re not sphexish – at least a little bit?

Modern theories of cognition all propose, in one way or another, that in fact we all are a little bit sphexish.  In fact, many of these theories, in emphasizing the pervasiveness of unconscious processing and the rarity and difficulty of analytic processing, are in effect proposing that our default mode of processing is sphexish.


[Excerpt] Linear Grammar as Protolanguage

Part Of: Language sequence
See Also: When Language Evolved
Excerpt From: (Johansson 2011) Constraining the Time When Language Evolved
Content Summary: 1600 words, 16 min read

The evolution of language had to involve at least a new ability to map concepts to sounds and gestures and to use these communicatively. But language actually consists of a good deal more than this: First, there is phonological structure—the systematized organization of sounds (or, in sign languages, gestures). Second is morphology—the internal structure of words, such that the word procedural can be seen as built from proceed plus -ure to form procedure, plus -al to form procedural: [[[proceed] [-ure]] [-al]]. Third is syntax, the organization of words into phrases and sentences.

One way to form plausible hypotheses about evolution is through reverse engineering: asking what components could have been useful in the absence of others. A primitive system for communicating thoughts via sound or gestures is useful without phonology, morphology, or syntax. The latter components can improve an existing communication system, but they are useless on their own. So if the components of language evolved in some order, it makes sense that the connection between phonetics and meaning came first, followed by these further refinements.

A system with a linear grammar would have words— that is, stored pairings between a phonological form and a piece of conceptual structure. The linear order of words in an utterance would be specified by phonetics, not by syntax. The individual words would map to meanings, but beyond linear order, there would be no further structure—no syntactic phrases that combine words and no morphological structure inside words (such as in the word procedural).

Language Evolution_ Linear vs Recursive Grammar (1)

Indeed, we can find evidence for linear grammar in many different contexts.

  1. As the early stages of contact languages, pidgins are often described as having no subordination, little or no morphology, no grammatical words like the, and unstable word order governed primarily by semantic principles like agent before action. If the context permits, the characters in the action can be left unexpressed. For instance, if the context had already brought the boy to attention, the speaker might just say girl kiss, which in English would require a pronoun—The girl kissed him. From the perspective of linear grammar, we can ask: Is there any evidence that pidgins have parts of speech like nouns and verbs, independently from the semantic distinction between individuals and actions? Indeed, there is no evidence for syntactic phrases, beyond semantic cohesion. Pidgin grammars are a good candidate for real-world examples of our hypothesized linear grammar.
  2. For a second case, involving late second language acquisition, Wolfgang Klein and Clive Perdue did a multilanguage longitudinal study of immigrants learning various second languages all over Europe. They found that all speakers achieved a stage of semiproficiency that they called the Basic Variety. Many speakers went on to improve on the Basic Variety, but others did not. At this stage, there is no inflectional morphology or sentential subordination, and known characters are freely omitted. Instead, there are simple, semantically based principles of word order including, for instance, agent before action.
  3. A third case is home signs, the languages invented by deaf children who have no exposure to a signed language. Susan Goldin-Meadow has shown that they have at most rudimentary morphology; they also freely omit known characters. In our analysis, home signs only have a semantic distinction of object versus action, not a syntactic distinction of noun versus verb. Word order is probabilistic and is based, if anything, on semantic roles. Homesigners do produce some sentences with multiple verbs, which Goldin-Meadow describes as embedding. We think these are rudimentary serial verb or serial action-word constructions, without embedding, sort of like the compound verb in English expressions such as He came running. So this looks like a linear grammar with possibly a bit of morphology.
  4. Another case is village sign languages, which develop in isolated communities with a significant occurrence of hereditary deafness. A well-known example is Central Taurus Sign Language (CTSL), spoken in two remote villages in the mountains of Turkey. CTSL has some minimal morphology, mostly confined to younger speakers. But there is little or no evidence for syntactic structure. In sentences involving one character, the word order is normally agent + action, and two-character sentences are normally (optional) agent + patient + action: girl ball roll. But if a sentence involves two animate characters, so that semantics alone cannot resolve the potential ambiguity, word order is not very reliable. For instance, girl boy hit is a bit vague about whether the girl hit the boy or vice versa, requiring a huge reliance on pragmatics, common knowledge, and context. In fact, there is a strong tendency to mention only one animate character per predicate, so speakers sometimes clarify by saying things like Girl hit, boy get-hit. So CTSL looks like a linear grammar, augmented by a small amount of morphology. Similar results have been obtained in Al-Sayyid Bedouin Sign Language (ABSL) and the earlier stages of Nicaraguan Sign Language.
  5. These less complex systems are not confined to emerging languages; they also play a role in language processing. Townsend and Bever (2001) discuss what they call semantically based interpretive strategies that influence language comprehension. In particular, hearers tend to rely in part on semantically based principles of word order such as agent precedes action, which is why (in our account) speakers have more difficulty with constructions such as reversible passives and object relatives, in which the agent does not precede the action. Similarly, Ferreira and Patson (2007) discuss good enough parsing, in which listeners apparently rely on linear order and semantic plausibility rather than syntactic structure. It is well known that we see similar though amplified symptoms in language comprehension by agrammatic aphasics. Finally, Van der Lely and Pinker (2014) argue that a particular population of children with specific language impairment behave as though they are processing language through something like a linear grammar. The literature frequently describes these so-called heuristics as something separate from language. But they are still mappings between phonetics and meaning—just simpler ones.
  6. We have also encountered a full-blown language whose grammar appears to be close to a linear grammar: Riau Indonesian, a vernacular with several million speakers, described by Gil (2005, 2009). Gil argues that this language has no syntactic parts of speech and no inflectional morphology such as tense, plural, or agreement. Known characters in the discourse are freely omitted. Messages that English expresses with syntactic subordination are expressed in Riau paratactically, with utterances like girl love, kiss boy. The word order is quite free, but agents tend to precede actions, and actions tend to precede patients. This collection of symptoms again looks very much like a linear grammar. Hence, this is a language virtually all of whose grammar is syntactically simple in our sense. Similar results obtain for the Piraha language, whose non-recursivity is well explained by the linear grammar theory as well.
  7. Another kind of linear grammar—that is, a system that relies on the linear order of the semantic roles being expressed to form conceptual relations—surfaces when people are asked to express actions or situations in a nonlinguistic task, such as in gesture or act-out tasks. Overall, there is a vast preference to gesture, or act out, the agent first (e.g., girl), and then the patient (e.g., boy). The action is usually expressed last (kiss), but when there is a potential ambiguity, people like to avoid it by expressing the action in the middle, between the agent and patient. Crucially, the ordering preferences in these tasks are remarkably stable, independently of the ordering preferences in test subjects’ native language. That seems to indicate that the capacity to map certain semantic notions to certain linear orders is at least partly independent from language itself.
  8. As a final case, traces of something like linear grammar lurk within the grammar of English! Perhaps the most prominent case is compounding, in which two words are stuck together to form a composite word. The constituents may be any part of speech: not just pairs of nouns, as in kitchen table, but also longbow, undercurrent, castoff, overkill, speakeasy, and hearsay. The meaning of the composite usually includes the meanings of the constituents, but the relation between them is determined pragmatically. Consider examples like these:
      • collar size = size of collar
      • dog catcher = person who catches dogs
      • nail file = something with which one files nails
      • beef stew = stew made out of beef
      • bike helmet = helmet that one wears while riding a bike
      • bird brain = person whose brain is similar to that of a bird

    The second noun usually determines what kind of object the compound denotes; for instance, beef stew is a kind of stew, whereas stew beef is a kind of beef. But this can be determined solely from the linear order of the nouns and needs no further syntax.

To sum up, remarkably similar grammatical symptoms turn up in a wide range of different scenarios. This suggests to us that linear grammar is a robust phenomenon, entrenched in modern human brains. It provides a scaffolding on top of which fully syntactic languages can develop, either in an individual, as in the case of the Basic Variety, or in a community, as in the case of pidgins and emerging sign languages. Furthermore, it provides a sort of safety net when syntactic grammar is damaged, as we have seen with aphasia and specific language impairment. We have also seen that it is possible to express a great deal even without syntax, for example in Riau Indonesian—though having syntax gives speakers more sophisticated tools for expressing themselves.

Language Evolution_ Linear Grammar

[Excerpt] When Language Evolved

Part Of: Language sequence
See Also: How Language Evolved
Excerpt From: (Johansson 2011) Constraining the Time When Language Evolved
Content Summary: 900 words, 9 min read

Speech is not impossible with an ape vocal tract, but merely less expressive, with fewer vowels available. Furthermore, the vocal tract in living mammals is quite flexible, and a resting position different from the human configuration does not preclude a dynamically lowered larynx, giving near-human vocal capabilities, during vocalizations.

Adaptations for speech can be found in our speech organs, hearing organs, the neural connections between these organs, as well as the genes controlling their development.

  • Speech organs. The shape of the human vocal tract, notably the permanently lowered larynx is very likely a speech adaptation, even though some other mammals, such as big cats, also possess a lowered larynx. The vocal tract itself is all soft tissue and does not fossilize, but its shape is connected with the shape of the surrounding bones, the skull base and the hyoid. Already Homo erectus had a near-modern skull base, but the significance of this is unclear, and other factors than vocal tract configuration, notably brain size and face size, strongly affect skull base shape. Hyoid bones are very rare as fossils, as they are not attached to the rest of the skeleton, but one Neanderthal hyoid has been found, as well as two hyoids from Homo heidelbergensis, all very similar to the hyoid of modern Homo sapiens, leading to the conclusion that Neanderthals had a vocal tract adequate for speech. The hyoid of Australopithecus afarensis, on the other hand, is more chimpanzee-like in its morphology, and the vocal tract that reconstruct for Australopithecus is basically apelike.
  • Hearing organs. Some fine-tuning appears to have taken place during human evolution to optimize speech perception, notably our improved perception of sounds in the 2-4 kHz range. The sensitivity of ape ears has a minimum in this range, but human ears do not, mainly due to minor changes in the ear ossicles, the tiny bones that conduct sound from the eardrum to the inner ear. This difference is very likely an adaptation to speech perception, as key features of some speech sounds are in this region. The adaptation interpretation is strengthened by the discovery that a middle-ear structural gene has been the subject of strong natural selection in the human lineage These changes in the ossicles were present already in the 400,000-year-old fossils from Spain, well before the advent of modern Homo sapiens. These fossils are most likely Homo heidelbergensis. In the Middle East, ear ossicles have been found both from Neanderthals and from early Homo Sapiens, likewise with no meaningful differences from modern humans.
  • Lateralization. There is no clearcut increase in general lateralization of the brain in human evolution — ape brains are not symmetric — and fossils are rarely undamaged and undistorted enough to be informative in this respect. But when tools become common, handedness can be inferred from asymmetries in the knapping process, the usewear damage on tools, and also in tooth wear patterns, which may provide circumstantial evidence of lateralization, and possibly language. Among apes there may be marginally significant handedness, but nothing like the strong population-level dominance of right-handers that we find in all human populations. Evidence for a human handedness pattern is clear among Neanderthals and their predecessors in Europe, as far back as 500 kya, and some indications go back as far as 1 mya. To what extent conclusions can be drawn from handedness to lateralization for linguistic purposes is, however, unclear.
  • Neural connections. Where nerves pass through bone, a hole is left that can be seen in well-preserved fossils. Such nerve canals provide a rough estimate of the size of the nerve that passed through them. A thicker nerve means more neurons, and presumably improved sensitivity and control. The hypoglossal canal, leading to the tongue, has been invoked in this context, but broader comparative samples have shown that it is not useful as an indicator of speech. A better case can be made for the nerves to the thorax, presumably for breathing control. Both modern humans and Neanderthals have wide canals here, whereas Homo erectus has the narrow canals typical of other apes, indicating that the canals expanded somewhere between 0.5 and 1.5 million years ago.
  • FOXP2. When mutations in the gene FOXP2 were associated with specific language impairment, and it was shown that the gene had changed along the human lineage, it was heralded as a “language gene”. But intensive research has revealed a more complex story, with FOXP2 controlling synaptic plasticity in the basal ganglia rather than language per se, and playing a role in vocalizations and vocal learning in a wide variety of species, from bats to songbirds. Nevertheless, the changes in FOXP2 in the human lineage quite likely are connected with some aspect of language, even if the connection is not as direct as early reports claimed. Relevant for the timing of the emergence of human language is that the derived human form of FOXP2 was shared with Neanderthals, and that the selective sweep driving that form to fixation may have taken place more than a million years ago, well before the split between Homo Sapiens and Neanderthals.

No single one of these indications is compelling on its own, but their consilience strengthens the case for some form of speech adaptations in Homo Heidelbergensis.

As the speech optimization, with its accompanying costs, would not occur without strong selective pressure for complex vocalizations, presumably verbal communication, this implies that Homo erectus already possessed non-trivial language abilities. While Homo erectus did not possess our species’ ability for ratcheting (cumulative) culture, it did exhibit art and sufficient skills to construct watercraft.

[Excerpt] Replicators and their Vehicles

Original Author: Richard Dawkins, The Selfish Gene
See Also: [Excerpt] The Robot’s Rebellion
Content Summary: 800 words, 4 min read

The First Replicator

Geochemical processes gave rise to the “primeval soup” which biologists and chemists believe constituted the seas some three to four thousand million years ago. The organic substances became locally concentrated, perhaps in drying scum round the shores, or in tiny suspended droplets. Under the further influence of energy such as ultraviolet light from the sun, they combined into larger molecules. Nowadays large organic molecules would not last long enough to be noticed: they would be quickly absorbed and broken down by bacteria or other living creatures. But bacteria and the rest of us are late-comers, and in those days large organic molecules could drift unmolested through the thickening broth.

At some point a particularly remarkable molecule was formed. We will call it the Replicator. It may not necessarily have been the biggest or the most complex molecule around, but it had the extraordinary property of being able to create copies of itself.

A molecule which makes copies of itself is not as difficult to imagine as it seems at first, and it only had to arise once. Think of the replicator as a mold or template. Imagine it as a large molecule consisting of a complex chain of various sorts of building block molecules. The small building blocks were abundantly available in the soup surrounding the replicator. Now suppose that each building block has an affinity for its own kind. Then whenever a building block from out in the soup lands up next to a part of the replicator for which it has an affinity, it will tend to stick there. The building blocks which attach themselves in this way will automatically be arranged in a sequence which mimics that of the replicator itself. It is easy then to think of them joining up to form a stable chain just as in the formation of the original replicator. Should the two chains split apart, we would then have two replicators, each of which can go on to make further copies.

Replicator Competition

The primeval soup was not capable of supporting an infinite number of replicator molecules. For one thing, the earth’s size is finite, but other limiting factors must also have been important.

But now we must mention an important property of the copying process: it is not perfect. mistakes will happen. I hope there will be no misprints in this book, but if you look carefully you may find one or two. We do not know how accurately the first replicator molecules made their copies. Their modern descendants, the DNA molecules, are astonishingly faithful compared with the most high-fidelity human copying process, but even they occasionally make mistakes, and it is ultimately these mistakes which make evolution possible. Mistakes were made, and these mistakes were cumulative.

Replicators with a comparatively worse design must actually have become less numerous because of competition, and ultimately many of their lines must have one extinct. There was a struggle for existence among replicator varieties. They did not know they were struggling, or worry about it; the struggle was conducted without any hard feelings, indeed without feeling of any kind. But they were struggling, in the sense that any mis-copying which resulted in a new improved level of stability, or a new way of reducing the stability of rivals, was automatically preserved and multiplied.

This process of replicator improvement was cumulative. Ways of increasing stability and of decreasing rivals’ stability became more elaborate and more efficient. Some of them may even have ‘discovered’ how to break up molecules of rival varieties chemically, and to use the building blocks so released for making their own copies. These proto-carnivores simultaneously obtained food and removed competing rivals. Other replicators perhaps discovered how to protect themselves, either chemically, or by building a physical wall of protein around themselves. This may have been how the first living cells appeared.

Replicator Self-Improvement

Replicators began not merely to exist, but to construct for themselves containers, vehicles for their continued existence. The replicators that survived were the ones that built survival machines for themselves to live in. The first survival machines probably consisted of nothing more than a protective coat. But making a living got steadily harder as new rivals arose with better and more effective survival machines. Survival machines got bigger and more elaborate, and the process was cumulative and progressive.

Was there to be any end to the gradual improvement in the replicators’]techniques? What weird engines of self-preservation would the millennia bring forth?  Four thousand million years on, what was to be the fate of the ancient replicators?

They did not die out, for they are past masters of the survival arts. But do not look for them floating loose in the sea; they gave up that cavalier freedom long ago. Now they swarm in huge colonies, safe inside gigantic lumbering robots, sealed off from the outside world, communicating with it by tortuous indirect routes, manipulating it by remote control..

They are in you and in me; they created us, body and mind; and their preservation is the ultimate rationale for our existence. They have come a long way, those replicators. Now they go by the name of genes, and we are their survival machines.

[Excerpt] Self-domestication and human homosexuality

Excerpts are not my writing! This comes from Richard Wrangham’s book:

The Goodness Paradox: The Strange Relationship Between Virtue and Violence in Human Evolution

It was a fun read. Recommended!

Human homosexuality is not adaptive

The hypothesis that human homosexuality is adaptive (genetically advantageous) has not been rejected lightly. Homosexual behavior can be frequently found among wild animals, and traits that are widespread are likely to be adaptive.

So when evolutionary biologists began to study human homosexual behavior, they tended to search for ways to explain how a same-sex preference might have been favored in natural selection. Homosexual behavior among other animals offered some ideas.

Close study reveals how homosexual behavior can be adaptive.

  1. Scarcity of opposite-sex partners. Among Laysan albatrosses in Hawaii, two parents are needed for chicks to be reared successfully. When there are not enough males, females pair together. Their sexual behavior includes courtship and pseudo-copulation. Females in same-sex pairs are fertilized by an already mated male, who then ignored the resulting eggs and chicks. The female pair brings them up without male help.
  2. As a prosocial device. In animals whose choice of sexual partner is not a response to a shortage of opposite-sex partners, homosexual behavior sometimes appears to be adaptive by promoting useful social relationships. In troops of Japanese monkeys, females form temporary homosexual mating partnerships even when other males are available. Among savanna baboons, males form alliances that they use in fights against others. Allies reciprocally fondle one another’s genitals, apparently to demonstrate their commitment to the bond.

Researchers have sought evidence that the kinds of reproductive or social benefits that animals gain from same-sex sexual interaction might be found in human. In theory, humans could form same-sex partnerships in response to a short supply of members of the opposite sex. Certainly, partner availability influences us. Women and men in single-sex institutions such as prisons, schools, monasteries, and ships often temporarily shift their sexual activity toward their own sex. Nevertheless, of course, many individuals feel an exclusive attraction to members of their own sex, regardless of the availability of the opposite sex.

Further, homosexual couples tend to have smaller families than same-sex couples, and there is a lack of evidence that their sexual orientation leads them to give exceptional help to their genetic kin. These data suggest that homosexual behavior in humans is not biologically adaptive.

Unfortunately, the conclusion that same-sex behavior is not adaptive has sometimes been associated with a negative view of homosexuality. But normative value and biological purpose are independent considerations. Many tendencies that we regard as morally reprehensible clearly evolved, including numerous kinds of sexual coercion, lethal violence, and social domination. Equally, many morally delightful tendencies did not evolve, such as charity to strangers and kindness to animals. Our decisions about which behavior we like or dislike should never be attributed to adaptive value.

The biological basis of homosexuality

Same-sex sexual attraction is often stable over a lifetime, and there is good evidence that is is partly heritable. These features make human homosexuality different from most animal homosexuality.

One particular area of the brain responds to androgens (sex hormones) in the fetal stage: the third interstitial nucleus of the anterior hypothalamus (INAH3). The INAH3 is larger in heterosexual men than in women, and has been found to be intermediate-sized in homosexual men. In an adult rams, experimentally reducing the comparable nucleus (oSDN) causes them to change his sexual-partner preference from female to male.

Homosexual preference is more likely in males who receive low testosterone exposure before birth. A standard method for assaying prenatal testosterone exposure is to measure the length of the ring finger (the fourth finger) compared to the length of the second finger: increased prenatal exposure to testosterone tends to be associated with relatively long ring fingers. The largest surveys of homosexual men in the United States, China, and Japan have found a tendency for homosexual women to have relatively long ring fingers, whereas homosexual men have relatively short ring fingers. Homosexual men also tend to have somewhat feminized face shapes and shorter, lighter bodies than heterosexual men, most likely from relatively low exposure to testosterone in the womb. In general, females who have been exposed to higher-than-usual levels of androgens, and males who have been exposed to lower-than-usual levels, appear to have a higher likelihood of being homosexual.

Homosexuality as a by-product of self-domestication

The evidence that exclusive homosexual preference is common but not adaptive makes it a prime candidate for being an evolutionary by-product.

Elsewhere, I have presented the self-domestication hypothesis: the theory that H. sapiens domesticated itself; that is, it selected against reactive aggression. Testosterone is involved both in male violence, but also sexual preference.

But since reduced testosterone is a common effect of domestication, homosexual orientation in this species appears to be explicable ultimately as an incidental consequence of selection against reactive aggression.

Some additional evidence are suggestive:

  • The only nonhuman animal in which exclusive homosexual preference is known is a domesticated species – namely, sheep.
  • At least 19 species of domesticated animals show homosexual behavior, though it occurs in their wild relatives as well.
  • Our two closest primate relatives are chimpanzees and bonobos. Chimpanzees are non-domesticated (highly aggressive) and have long ring fingers suggesting high prenatal exposure to testosterone. Bonobos are self-domesticated (placid), and have short index fingers.
  • Homo neanderthalensis morphology indicates they were quite an aggressive species (non-domesticated), and they shows a large finger-length ratio. The 100,000-year-old H. sapiens at Qafzeh is in-between the ratios for living humans and the five Neanderthals.

Thus, it may be that self-domestication (the source of our species’ remarkable ability for cooperation) yielded homosexual behaviors as a by-product.



[Excerpt] The Tragedy of Commonsense Morality

Part Of: Demystifying Ethics sequence
Content Summary: 1500 words, 15 min read.

Excerpts are not my writing! This comes from Joshua Greene’s excellent book:

Moral Tribes: Emotion, Reason, and the Gap between Us and Them

The book goes on to present an interesting solution to the below problem. Check it out!

The Tragedy of the Commons

The following parable – entitled tragedy of the commons – originates from Garrett Hardin’s 1968 paper:

A single group of herders shares a common pasture. The commons is large enough to support many animals, but not infinitely many. From time to time, each herder must decide whether to add another animal to her flock. What’s a rational herder to do? By adding an animal to her herd, she receives a substantial benefit when she sells the animal at market. However, the cost of supporting that animal is shared by all who use the commons. Thus, the herder gains a lot, but pays only a little, by adding an additional animal to her herd. Therefore, she is best served by increasing the size of her herd indefinitely, so long as the commons remains available. Of course, every other herder has the same set of incentives. If each herder acts according to her self-interest, the commons will be completely eroded, and there will be nothing left for anyone.

You may recognize the economic structure of this game from the Prisoner’s Dilemma. To win such a game, you must find the magic corner; that is, to accomplish cooperative outcomes despite the temptation of selfishness.

The problem of cooperation is the central problem of social existence. Fortunately, our brains come equipped with the following mechanisms, all of which foster cooperation.

  1. Concern for others. Two prisoners can find the magic corner if they place some value on each other’s payoffs in addition to their own.
    • Faculties: empathy, violence aversion.
  2. Direct reciprocity. Two prisoners can find the magic corner if they know that being uncooperative now will deny the benefits of future cooperation.
    • Faculties: punitive motivation, forgiveness, gratitude
  3. Commitments. Two prisoners can find the magic corner if they are committed to punishing each other’s uncooperative behavior.
    • Faculties: shame, guilt, loyalty.
  4. Reputation. Two prisoners can find the magic corner if they know that being uncooperative now will deny us the benefits of future cooperation with others.
    • Faculties: gossip, embarrassment.
  5. Assortment. Two prisoners can find the magic corner by belonging to a cooperative group, provided that group members can reliably identify one another.
    • Faculties: identity markers, tribalism

We have cooperative brains, it seems, because cooperation provides material benefits, biological resources that enable our genes to make more copies of ourselves. Out of evolutionary dirt grows the flower of human goodness.

The Tragedy of Common Sense Morality

To the east of a deep, dark forest, a tribe of herder raise sheep on a common pasture. Here the rule is simple: each family gets the same number of sheep. Families send representatives to a council of elders, which governs the commons. Over the years, the council has made difficult decisions. One family, for example, took to breeding exceptionally large sheep, thus appropriating more of the commons for itself. After some heated debate, the council put a stop to this. Another family was caught poisoning its neighbors’ sheep. For this the family was severely punished. Some said too severely. Others said not enough. Despite these challenges, the Eastern tribe has survived, and its families have prospered, some more than others.

To the west of the forest is another tribe whose herders also share a common pasture. There, however, the size of a family’s flock is determined by the family’s size. Here, too, there is a council of elders, which has made difficult decisions. One particularly fertile family had twelve children, far more than the rest. Some complained that they were taking  up too much of the commons. A different family fell ill, losing five of their six children in one year. Some thought it was unfair to compound their tragedy by reducing their wealth by more than half. Despite these challenges, the Western tribe has survived, and its families have prospered, some more than others.

To the north of the forest is yet another tribe. Here there is no common pasture. Each family has its own plot of land, surrounded by a fence. These plots vary greatly in size and fertility. This is partly because some Northern herders are wiser and more industrious than others. Many such herders have expanded their lands, using their surpluses to buy land from their less prosperous neighbors. Some Northern herders are less prosperous than others simply because they are unlucky, having lost their flock or their children to disease. Still other herders are exceptionally lucky, possessing large fertile plots of land, not because they are especially industrious but because they inherited them. Here in the North, the council of elders doesn’t do much. They simply ensure that herders keep their promises and respect one another’s property. The vast differences in wealth among Northern families has been the source of much strife. Each year, some Northerners die in winter for want of food and warmth. Despite these challenges, the Northern tribe has survived, and its families have prospered, some more than others.

To the south of the forest is a fourth tribe. They share not only their pasture but their animals, too. Their council of elders is very busy. The elders manage the tribe’s herd, assign people to jobs, and monitor their work. The fruits of this tribe’s labor are shared equally among all its members. This is a source of much strife, as some tribe members are wiser and more industrious than others. The council hears many complaints about lazy workers. Most members, however, work hard. Some are moved to work by community spirit, others by fear of their neighbor’s reproach. Despite these challenges, the Southern tribe has survived. Its families are not, on average, as prosperous as those in the North, but they do well enough, and in the South no one has ever died in winter for want of food or warmth.  

One summer, a great fire burned through the forest, reducing it to ash. Then came heavy rains, and before long the land, once thick with trees, was transformed into an expanse of gently rolling grassy hills, perfect for grazing animals. The nearby tribes rushed in to claim the land. This was a source of much strife. The Southern tribe proclaimed that the new pastures belonged to all people and must be worked in common. They formed a new council to manage the new pastures and invited the other tribes to send representatives. The Northern herders scoffed at this suggestion. While the Southerners were making their big plans, Northern families built houses and stone walls and set their animals to graze. Many Easterners and Westerners did the same, though with less vigor. Some families sent representatives to the new council.

The four tribes fought bitterly, and many lives, both human and animal were lost. Small quarrels turned into bloody feuds, which turned into deadly battles. A Southern sheep slipped into a Northerner’s field. The Northerner demanded a fee to return it. The Southerners refused to pay. The Northerner slaughtered the sheep. The Southerners took three of the Northerner’s sheep and slaughtered them. The Northerners took ten of the Southerner’s sheep and slaughtered them. The Southerners burned down the Northerners farmhouse, killing a child. Ten Northern families marched on the Southerner’s meeting house and set it ablaze, killing dozens of Southerners, including many children. Back and forth they went with violence and vengeance, soaking the green hills with blood.

The tribes of the new pastures are engaged in bitter, often bloody conflict, even though they are all, in their different ways, moral peoples. They fight not because they are fundamentally selfish but because they have incompatible visions of what a moral society should be. These are not mere scholarly disagreements, although their scholars have those, too. Rather, each tribe’s philosophy is woven into its daily life. Each tribe has its own version of moral common sense. The tribes of the new pastures fight not because they are immoral but because they view life on the new pastures from very different moral perspectives. I call this the Tragedy of Commonsense Morality.

Five psychological tendencies tend to exacerbate intertribal conflict:

  1. Naked group selfishness. Human tribes are tribalistic, favoring Us over Them.
  2. Moral disagreement. Tribes have genuine disagreements about how societies should be organized, with different emphases on e.g., the rights of individuals versus the greater good.
  3. Authority question begging. Tribes have distinctive moral commitments, whereby moral authority is vested in local individuals, texts, traditions and deities that other groups don’t recognize as authoritative.
  4. Asymmetry capitalization. Tribes are prone to biased fairness, allowing group-level self-interest to distort their sense of justice
  5. Punitive escalation. The way we process information about social events can cause us to underestimate the harm we cause others, leading to the escalation of conflict.

Morality is nature’s solution to the Tragedy of the Commons, enabling us to put Us ahead of Me. But nature has no ready-made solution to the Tragedy of Commonsense Morality, the problem of enabling Us to get along with Them. And therein lies our problem. If we are to avert the Tragedy of Commonsense Morality, we’re going to have to find our own, unnatural solution: what I’ve called a metamorality, a higher-level moral system that adjudicates among competing tribal moralities, just as a tribe’s morality adjudicates among competing individuals.

[Excerpt] The Three Spheres of Culture

The Three Sphere Hypothesis

Most people agree that human societies operate in different contexts: markets, governments, and communities. The Three Sphere Hypothesis holds that this trichotomy is fundamental and exhaustive of social space. What’s more, these spheres interact. Neither markets nor governments nor communities can be analyzed thoroughly without understanding their dependence upon, and their effects upon, the others.

Relational Models_ Cultural Regime Dissociations (4)

[Excerpt] Intellectual History of the Hypothesis

Source: Wicks (2009). A Model of Dynamic Balance among the Three Spheres of Society

Social scientists – including economists – as well as journalists and others, often refer to “the economic, political, and social conditions” underlying any particular situation, but usually without any further analysis of what these terms imply, and how they relate to each other.

Apparent references to these three spheres pop up – in both popular and technical literature – almost everywhere. It can be a fun game, like “whack-a-mole”:

  • Where and how will the three spheres “pop up” in this or that text?
  • And, given any set of three social attributes that do “pop up”, can they be seen in some way as representing the three spheres?

Etzioni (1996:122) speaks of “three different conditions: paid, coerced, or convinced”; Etzioni (1988) explores motivations in the community sphere at length.

Personalist economics, based on Catholic theology, also recognizes three organizing principles: competition, intervention, and cooperation (Jonish and Terry, 1999:465-6; O’Boyle, 1999:536-7, 2000:550-51).

Hirschman (1992) referred to three social mechanisms: exit, voice, and loyalty. Though all three can apply in varying ways to each sphere, exit refers primarily to the market sphere where, in a competitive situation, one has unlimited choice of buyers or sellers, so can “exit” from any one. Voice might refer primarily to the political sphere, where one can attempt to influence results by persuasion, and loyalty to the community sphere – though one could argue the other way as well.

Streeck and Smitter (1985:1) refer to these “three basic mechanisms of mediation or control” (Ouchi, 1980) as spontaneous solidarity, hierarchical control, and dispersed competition.

Friedland and Alford (1991:39) refer to three domains with different “logics of action”: In the marketplace, we are more likely to base our actions on individual utility and efficient means; in the polity, on democracy and justice; and in the family, on mutual support.

Van Staveren (2001:24) asserts that “three values appear time and again in economic analysis: liberty, justice, and care. Markets tend to express freedom, states to express justice, and unpaid labor to express care among human beings.” She notes (p. 213) that Ayres (1961:170) asserted a similar set of core human values: “freedom, equality, and security”. Van Staveren (p. 203) also notes:

  • the form that these values take: exchange, redistribution, and giving;
  • the locations where they operate: market, state, and the care-economy; and
  • the corresponding virtues: prudence, propriety, and benevolence.

She further asserts that there are “distinct emotions and forms of deliberation as well”.

Mackey (2002:384) refers to “economic, political, and social problems” in Saddam’s Iraq; elsewhere (p. 181) she uses a different order, referring to “the new political, social, and economic paradigm” (an order which Rothstein and Stolle, 2007:1, also use); and yet elsewhere (p. 49) she notes that something “meant more socially, politically, and economically”. The order of expression doesn’t seem to matter, to Mackey or to most other authors, and one can easily find the other three permutations as well (e.g., Friedman, 2000:131; Giddens and Pierson, 1998:89; Sage, 2003).

But the community sphere is often ignored, and thus is sometimes considered third (Adaman and Madra, 2002). In political theory, the “Third Way” (Giddens, 1998) represents an alternative to either markets or governments, focused more in communities.

Waterman (1986:123) asserts “three freedoms: economic, political, and religious (conscience)”; and Hobson (1938/1976:52) refers to “the democratic triad of liberty, equality, fraternity”.

As some of these examples illustrate, a wide variety of words are used to refer to the three spheres, as in the title of the book (cited by Bennett, 1985) Mexico: Catholicism, Capitalism, and the State, or when

  • Mackey (2002:217) discusses “political, economic, and… cultural control”;
  • Bowles (1998:105) refers to “states, communities, and markets”;
  • Wright (2000:211) refers to “governance, moral codes, and markets”;
  • Mauss (1925/1967:52) refers to the “law, morality, and economy of the Latins” and to “the distinction between ritual, law, and economic interest”;
  • Yuengert (1999:46) discusses “free markets circumscribed within a tight legal framework, and operating within a humane culture”;
  • Polanyi (1997:140), in discussing “economic life”, refers to “freedom under law and custom, as laid down and amended when necessary by the State and public opinion”.

In The Foundations of Welfare Economics (1949:230), Little points out that “if a person argues that a certain change would increase economic welfare, it is open to anyone to argue that it would decrease spiritual or political welfare.”

This tripartite taxonomy has been used by economists since Adam Smith who, of course, had first written The Theory of Moral Sentiments (1759/1982) about communities and social goods, then The Wealth of Nations (1776/1976) about markets, economics. But he was planning a third major work – which was never completed – on the political system (Smith, 1759/1982:342 and “Advertisement” therein).

Minowitz (1993) uses the same tripartite taxonomy twice (in varying order) in the title of his book: Profits, Priests, and Princes: Adam Smith’s Emancipation of Economics from Politics and Religion.

The English economist and theologian Philip Wicksteed referred to “business, politics, and the pulpit” in his book of sermons titled Is Christianity Practical? (1885/1920, referenced in Steedman 1994:83). In discussing Wicksteed’s work, Steedman (p. 99) also refers to “potatoes, politics, and prayer”. Similarly, Hobson (1938/1976:55) referred to “the purse, power, and prestige of the ruling classes in business, politics, and society”. Success itself is often defined as “wealth, fame, and power” (Bogle, 2004:1; Carey, 2006), or sometimes as “money, status, and power”.

A similar tripartite taxonomy – perhaps Marxian – of firms, social classes, and states, can easily be seen as referring to the three spheres.

According to Trotsky (1957:255), communism would demonstrate that the human race had “ceased to crawl on all fours before God, kings, and capital” (quoted by Minowitz, 1993:240).

A variety of sources also provide evidence of an apparently widespread belief that the three spheres are both fundamental and exhaustive of social space. Michael Novak refers to the “three mutually autonomous institutions: the state, economic institutions, and cultural, religious institutions” as “the doctrine of the trinity in democratic capitalism” (Abdul-Rauf, 1986:175; also Neuhaus, 1986:517).

Dasgupta (1993:104) notes “one overarching idea, that of citizenship, with its three constituent spheres: the civil, the political, and the socio-economic.”

Meyer et al. (1992:12) assert that “individuals must acquire the means to participate effectively in the economic, social, and political life of the nation.” In the same work, Wong (1992:141) makes it clear that these three spheres are considered exhaustive by referring to “all social domains… economy… polity… and… cultural system”.

Polanyi (1997:158) describes the Russian Revolution and the Soviets’ “project for a new economic, political, and social system of mankind”.

Shadid (2001:3) points out that “political Islam, or Islamism…suggests an all-embracing approach to economics, politics, and social life.”

Dicken (2007:538) says that “corporate social responsibilities span the entire spectrum of relationships between firms [and] states, civil society, and markets.”


[Excerpt] The Finite Price of Human Life

Content Summary: 1400 words, 7 min read.
Original Author: Scott Alexander

Price of Life

Recently on both sides of the health care debate I have been hearing people make a very dangerous error. They point to a situation in which someone was denied coverage for a certain treatment because it was expensive and unproven, and say: “This is an outrage! We can’t let ‘death panels’ say some lives aren’t worth saving! How can people say money is more important than a human life? We have a moral duty to pay for any treatment, no matter how expensive, no matter how hopeless the case, if there is even the tiniest chance that it help this poor person.”

All of these are simple errors. Contrary to popular belief, you can put a dollar value on human life. That dollar value is $5.8 million. Denying this leads to terrible consequences.

Let me explain.

On The Risks of Dying

Consider the following:

A man has a machine with a button on it. If you press the button, there is a one in five million chance that you will die immediately; otherwise, nothing happens. He offers you some money to press the button once. What do you do? Do you refuse to press it for any amount? If not, how much money would convince you to press the button?

What do you think?

If you answered something like “Never for any amount of money,” or “Only for a million dollars”, you’re not thinking clearly.

One in five million is pretty much your chance of dying from a car accident every five minutes that you’re driving. Choosing to drive for five minutes is exactly equivalent to choosing to press the man’s button. If you said you wouldn’t press the button for fifty thousand dollars, then in theory if someone living five minutes away offers to give you fifty thousand dollars no strings attached, you should refuse the offer because you’re too afraid to drive to their house.

Likewise, if you drive five minutes to a store to buy a product, instead of ordering the same product on the Internet for the same price plus $5 shipping and handling, then you should be willing to press the man’s button for $5.

When I asked this question to several friends, about two-thirds of them said they’d never press the button. This tells me people are fundamentally confused when they consider the value of life. When asked directly how much value they place on life, they always say it’s infinite. But people’s actions show that in reality they place a limited value on their life; enough that they’re willing to accept a small but real chance of death to save five bucks. And as we will see, that is a very, very good thing.

Insurance Example: Fixed Costs

Consider the following:

Imagine an insurance company with one hundred customers, each of whom pays $1. This insurance company wants 10% profit, so it has $90 to spend. Seven people on the company’s plan are sick, with seven different diseases, each of which is fatal. Each disease has a cure. The cures cost, in order, $90, $50, $40, $20, $15, $10, and $5.

We have decided to give everyone every possible treatment. So when the first person, the one with the $90 disease, comes to us, we gladly spend $90 on their treatment; it would be inhuman to just turn them away. Now we have no money left for anyone else. Six out of seven people die.

The fault here isn’t with the insurance company wanting to make a profit. Even if the insurance company gave up its ten percent profit, it would only have $10 more; enough to save the person with the $10 disease, but five out of seven would still die.

A better tactic would be to turn down the person with the $90 disease. Instead, treat the people with $5, $10, $15, $20, and $40 diseases. You still use only $90, but only two out of seven die. By refusing treatment to the $90 case, you save four lives. This solution can be described as more cost-effective; by spending the same amount of money, you save more people. Even though “cost-effectiveness” is derided in the media as being opposed to the goal of saving lives, it’s actually all about saving lives.

If you don’t know how many people will get sick next year with what diseases, but you assume it will be pretty close to the amount of people who get sick this year, you might make a rule for next year: Treat everyone with diseases that cost $40 or less, but refuse treatment to anyone with diseases that cost $50 or more.

Insurance Example: Probabilistic Costs

There is a similar argument applies to medical decisions that involve risk. Consider:

You have $900. There are four different fatal diseases: A, B, C, and D. There are 40 patients, ten with each disease. with four different fatal diseases. Each disease costs $300 to cure.

In this case, your only option is to cure A, B, and C… and tell patients with D that unfortunately there’s not enough left over for them.

But what if the cure for A only had a 10% chance of working? In this case, you cure A, B, and C and have, on average, 21 people left alive.

Or you could tell A that you can’t approve the treatment because it’s not proven to work. Now you use your $90 to treat B, C, and D instead, and you have on average 30 people left alive. By denying someone an unproven treatment, you’ve saved 9 lives.

Computing the Value of a Life

So, in the real world, how should we decide how much money is a good amount to spend on someone?

I mentioned before that people don’t act as if the lives of themselves or others are infinitely valuable. They act as if they have a well-defined price tag. Well, some enterprising economists have figured out exactly what that price tag is. They made their calculations by examining, for example, how much extra you have to pay someone to take a dangerous job, or how much people who are spending their own money are willing to spend on unproven hopeless treatments. They determined that most people act as if their lives were worth, on average, 5.8 million dollars.

Most health care, government or private, uses a similar calculation. One common practice is to value an extra year of healthy life at $50,000. So:

  1. If a treatment costs $60,000 and will only let you live another year, they’ll reject it.
  2. If a treatment costs $600,000 and will let you live 20 more years, then since 600000/20 = 30,000 which is < 50,000, they’ll approve it.
  3. If a treatment costs $15,000 and has only a one in ten chance of letting you live another two years, then since [(15000)/(1/10)]/2 = 75,000 which is > 50,000, they’ll reject it.

I’m not claiming I have any of the answers to this health care thing. I’m not claiming that $50,000 is or isn’t a good number to value a year of life at. I’m not saying that government health care couldn’t become much more efficient and save lots of money, or that private health care couldn’t come up with a better incentive system that makes denying treatments less common and less traumatizing. I’m not saying that insurance companies don’t make huge and stupid mistakes when performing this type of analysis, or even that they aren’t the slime of the earth. I’m not saying the insurance system is currently fair to the poor, whatever that means. I’m not saying that there aren’t many many variables not considered in this simplistic analysis, or anything of that sort.

I am saying that if you demand that you “not be treated as a number” or that your insurance “never deny anyone treatment as long as there’s some chance it could help”, or that health care be “taken out of the hands of bureaucrats and economists”, then you will reap what you have sown: worse care and a greater chance of dying of disease, plus the certainty that you have inflicted the same on many others.

I’m also saying that this is a good example of why poorly informed people who immediately get indignant at anything packaged by the media as being “outrageous”, even when their “hearts are in the right places”, end up poisoning a complicated issue and making it harder for responsible people to make any progress.

[Excerpt] An Unfortunate Dualist

Part Of: Philosophy of Mind sequence
Content Summary: 500 words, 5 min read

Once upon a time there was a dualist. He believed that mind and matter are separate substances. Just how they interacted he did not pretend to know-this was one of the “mysteries” of life. But he was sure they were quite separate substances.

This dualist, unfortunately, led an unbearably painful life – not because of his philosophical beliefs, but for quite different reasons. And he had excellent empirical evidence that no respite was in sight for the rest of his life. He longed for nothing more than to die. But he was deterred from suicide by such reasons as:

  1. he did not want to hurt other people by his death;
  2. he was afraid suicide might be morally wrong;
  3. he was afraid there might be an afterlife, and he did not want to risk the possibility of eternal punishment.

So our poor dualist was quite desperate.

Then came the discovery of the miracle drug! Its effect on the taker was to annihilate the soul entirely but to leave the body functioning exactly as before. Absolutely no observable change came over the taker; the body continued to act just as if it still had a soul. Not the closest friend or observer could possibly know that the taker had taken the drug, unless the taker informed him.

Do you believe that such a drug is impossible in principle? Assuming you believe it possible, would you take it? Would you regard it as immoral? Is it tantamount to suicide? Is there anything in Scriptures forbidding the use of such a drug? Surely, the body of the taker can still fulfill all its responsibilities on earth. Another question: Suppose your spouse took such a drug, and you knew it. You would know that she (or he) no longer had a soul but acted just as if she did have one. Would you love your mate any less?

To return to the story, our dualist was, of course, delighted! Now he could annihilate himself (his soul, that is) in a way not subject to any of the foregoing objections. And so, for the first time in years, he went to bed with a light heart, saying: “Tomorrow morning I will go down to the drugstore and get the drug. My days of suffering are over at last!” With these thoughts, he fell peacefully asleep.

Now at this point a curious thing happened. A friend of the dualist who knew about this drug, and who knew of the sufferings of the dualist, decided to put him out of his misery. So in the middle of the night, while the dualist was fast asleep, the friend quietly stole into the house and injected the drug into his veins. The next morning the body of the dualist awoke -without any soul indeed- and the first thing it did was to go to the drugstore to get the drug. He took it home and, before taking it, said, “Now I shall be released.” So he took it and then waited the time interval in which it was supposed to work. At the end of the interval he angrily exclaimed: “Damn it, this stuff hasn’t helped at all! I still obviously have a soul and am suffering as much as ever!”

(This parable was inspired by one written by Raymond M. Smullyan)

[Excerpt] The Hiccups Of Your Inner Fish

Excerpt From: Your Inner Fish
Content Summary: 1000 words, 5 min read

The annoyance of hiccups has its roots in the history we share with fish and tadpoles.

If there is any consolation for getting hiccups, it is that our misery is shared with many other mammals. Cats can be stimulated to hiccup by sending an electrical impulse to a small patch of tissue in their brain stem. This area of the brain stem is thought to be the center that controls the complicated reflex that we call a hiccup.

The hiccup reflex is a stereotyped twitch involving a number of muscles in our body wall, diaphragm, neck, and throat. A spasm in one or two of the major nerves that control breathing causes these muscles to contract. This results in a very sharp inspiration of air. Then, about 35 milliseconds later, a flap of tissue in the back of our throat (the glottis) closes the top of our airway. The fast inhalation followed by a brief closure of the tube produces the “hic”.

The problem is that we rarely experience only a single hic. Stop the hiccups in the first five to ten hics, and you have a decent chance of ending the bout altogether. Miss that window, and the bout of hiccups can persist for an average of about sixty hics. Inhaling carbon dioxide (by breathing into the classic paper bag) and stretching the body wall (taking a big inhalation and holding it) can end hiccups early in some of us. But not all. Some cases of pathological hiccups can be extremely prolonged. The longest uninterrupted hiccups in a person lasted from 1922 to 1990.

Our tendency to develop hiccups is another influence of our past. There are two issues to think about:

  1. What causes the spasm of nerves that initiates the hiccup.
  2. What controls the distinctive hic, the abrupt inhalation-glottis closure.

The nerve spasm is a product of our fish history, while the hic is an outcome of the history we share with animals such as tadpoles.

First, fish. Our brain can control our breathing without needing conscious effort on our part. Most of the work takes place in the brain stem, at the boundary between the brain and the spinal cord. The brain stem sends nerve impulses to our main breathing muscles. Breathing happens in a pattern. Muscles of the chest, diaphragm, and throat contract in a well-defined order. Consequently, this part of the brain stem is known as a “central pattern generator.” This region can produce rhythmic patterns of nerve and, consequently, muscle activation. A number of such generators in our brain and spinal cord control other rhythmic behaviors, such as swallowing and walking.

The problem is that the brain stem originally controlled breathing in fish; it has been jury-rigged to work in mammals. Sharks and bony fish all have a portion of the brain stem that controls the rhythmic firing of muscles in the throat and around the gills. The nerves that control these areas all originate in a well-defined portion of the brain stem. We can even see this nerve arrangement in some of the most primitive fish in the fossil record. Ancient ostracoderms, from rocks over 400 million years old, preserve casts of the brain and cranial nerves. Just as in living fish, the nerves that control breathing extend from the brain stem.

This works well in fish, but it is a lousy arrangement for mammals. In fish, the nerves that control breathing do not have to travel very far from the brain stem. The gills and throat generally surround this area of the brain. We mammals have a different problem. Our breathing is controlled by muscles in the wall of our chest and by the diaphragm, the sheet of muscle that separates our chest from our abdomen. Contraction of the diaphragm controls inspiration. The nerves that control the diaphragm exit our brain just as they do in fish, and they leave from the brain stem, near our neck. These nerves, the vagus and the phrenic nerve, extend from the base of the skull and travel through the chest cavity and reach the diaphragm and the portions of the chest that control breathing. This convoluted path creates problems; a rational design would have the nerves traveling not from the neck but from nearer the diaphragm. Unfortunately, anything that interferes with one of these nerves can block their function or cause a spasm.

If the odd course of our nerves is a product of our fishy past, the hiccup itself is likely the product of our history as amphibians. Hiccups are unique among our breathing behaviors in that an abrupt intake of air is followed by a closure of the glottis. Hiccups seem to be controlled by a central pattern generator in the brain stem: stimulate this region with an electrical impulse, and we stimulate hiccups. It makes sense that hiccups are controlled by a central pattern generator, since, as in other rhythmic behaviors, a set sequence of events happens during a hic.

It turns out that the pattern generator responsible for hiccups is virtually identical to one in amphibians. And not in just amphibians – in tadpoles, which use both lungs and gills to breathe. Tadpoles use this pattern generator when they breathe with gills. In that circumstance, they want to pump water into their mouth and throat and across the gills, but they do not want the water to enter their lungs. To prevent it from doing so, they close the glottis, the flap that closes off the breathing tube. And to close the glottis, tadpoles have a central pattern generator in their brain stem so that an inspiration is followed immediately by a closing glottis. They can breathe with their gills thanks to an extended form of hiccup.

The parallels between our hiccups and gill breathing in tadpoles are so extensive that many have proposed that the two phenomena are one and the same. Gill breathing in tadpoles can be blocked by carbon dioxide, just like our hiccups. We can also block gill breathing by stretching the wall of the chest, just as we can stop hiccups by inhaling deeply and holding our breath. Perhaps we could even block gill breathing in tadpoles by having them drink a glass of water upside down.