A Dual-Process Theory of Moral Judgment

Part Of: Demystifying Ethics sequence
Content Summary: 900 words, 9 min read

Trolleyology

An ethical theory is an attempt to explain what goodness is: to ground ethics in some feature of the world. We have discussed five such theories, including:

  • Consequentialism, which claims that goodness stems from the consequences of an action
  • Deontology, which claims that goodness stems from absolute obligations (discoverable in light of the categorical imperative)

For most behaviors (e.g., theft), both theories agree (in this case, label the act as Evil). But there do exist key scenarios which prompt these theories to disagree. Consider the switch dilemma:

Consider a trolley barreling down a track that will kill five people unless diverted. However, on the other track a single person has been similarly demobilized. Should you pull to lever to divert the trolley?

Our ethical theories produce the following advice:

  • Consequentialism says: pull the lever! One death is awful, but better than five.
  • Deontology says: don’t pull the lever! Any action that takes innocent life is wrong. The five deaths are awful, but not your fault.

Would you pull the lever? Good people disagree. However, if you are like most people, you will probably say “yes”. 

Things get interesting if we modify the problem as follows. Consider the footbridge dilemma:

Consider a trolley barreling down a track that will kill five people unless diverted. You are standing on a bridge with a fat man. If you push the fat man onto the track, the trolley will derail, sparing the five people.

Notice that the consequences for the action remain the same. Thus, consequentialism says “push the fat man!”, and deontology says “don’t push!”

What about you? Would you push the fat man? Good people disagree; however, most people confess they would not push the fat man off the bridge. 

Our contrasting intuitions are quite puzzling. After all, they only thing that’s different between the two cases is how close the violence is: far away (switch) vs up close (shoving).

Towards a Dual-Process Theory

Recall that there are two kinds of ethical theories.

  1. Prescriptive theories describe what goodness objectively is.
  2. Descriptive theories tell us how the brain produces moral judgments.

Consequentialism and deontology are prescriptive theories. However, we can also conceive of consequentialism and deontology as descriptive theories. Let’s call these descriptive variants folk consequentialism and folk deontology, respectively.

Sometimes, people’s judgments is better explained by folk consequentialism; other times, folk deontology enjoys more predictive success. We might entertain two hypotheses to explain this divergence:

  1. Different boundary conditions of a single neural process
  2. Two competing processes for moral judgment

As we will see, the evidence suggests that the second hypothesis, the dual-process theory of moral judgment, is correct.

Dissociation-Based Evidence

Consider the crying baby dilemma:

It’s wartime. You and your fellow villagers are hiding from nearby enemy soldiers in a basement. Your baby starts to cry, and you cover your baby’s mouth to block the sound. If you remove your hand, your baby will cry loudly, and the soldiers will hear. They will find you… and they will kill all of your. If you do not remove your hand, your baby will smother to death. Is it morally acceptable to smother your baby to death in order to save yourself and the other villagers?

Here, people take a long time to answer, and show no consensus in their answers. If the dual-process theory of moral judgment is correct, then we expect the following:

  1. Everyone exhibits increased activity in the dorsal anterior cingulate (dACC). This region is known to reliably respond when two or more incompatible behavioral responses are simultaneously activated. 
  2. For those who eventually choose the folk consequentialist answer (save the most lives) should exhibit comparatively more activity in brain regions associated with working memory and cognitive control.

Both predictions turn out to be true. Here then is the circuit diagram of our dual-process, organized in the two cybernetic loops framework:

Dual-Process Morality- System Architecture

Four other streams of evidence corroborate our dual-process theory:

  • Deontological judgments are produced more quickly than consequentialist ones.
  • Cognitive distractions slow down consequentialist but not deontological judgments.
  • Patients with dementia or lesions that cause “emotional blunting” are disproportionately likely to approve of consequentialist action. 
  • People who are either high in “need for cognition” and low in “faith in intuition”, or have unusually high working memory capacity, tend to produce more consequentialist judgments.

Relation To Other Disciplines

We have previously distinguished two kinds of moral machinery:

  • Propriety frames are a memory format that retains social intuitions.
  • Social intuition generators which contribute to the contents of social judgments.

These machines map to the dual-process theory of judgment. Propriety frames are housed in cerebral cortex, which perform folk consequentialist analysis. Social intuition generators are located within the limbic system, and contribute folk deontology intuitions.

Recall that Kantian deontology attempted to ground moral facts in pure reason (the categorical imperative). While surely valuable as a philosophical exercise, in practice folk deontological judgments have little to do with reason. They are instead driven by autonomic emotional responses. It is folk consequential judgments which depend more on reason (cortical reasoning).

This is not to say that people who prefer consequential reasoning are strictly superior moral judges. But I will address the question which reasoning system should I trust more? on another day.

Takeaways

  • For the switch dilemma, most people reason consequentially (“save the most lives”)
  • For the footbridge dilemma, most people reason deontologically (“murder is always wrong”)
  • These contrasting styles emerge because the brain has two systems of judgment.
  • Folk consequentist reasoning is performed in cerebral cortex.
  • Folk deontology intuitions are generated from within the limbic system.

Until next time.

An Introduction to Ethical Theories

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

Motivations

Ethics discussions can occur at different levels of abstraction. The most concrete ethical discussions involve discussing specific topics; e.g., “is abortion moral”? These scenarios are called applied ethics.

Spend enough time wrestling with applied ethics, and you’ll start wondering what all of these moral intuitions have in common. An ethical theory is an answer to the question “what makes a thing good or bad”?

Meta-ethics answers a yet broader set of questions. What is right and wrong, anyways? Are moral beliefs objectively true in the same sense that the Earth orbits the sun? Or is my condemning an unethical act merely expressing an aesthetic preference (“yuck!”)?

Ethical Theory- Three Abstraction Levels

Image Credit

Today we conduct a whirlwind tour of ethical theories, touching on the most influential theories. Ethical theories are normative: they speak to what moral conclusions ought to be. However, we will see later how these theories also sometimes imperfectly anticipate the emerging science of moral cognition.

We will discuss the following:

  1. Divine Command Theory
  2. Natural Law Theory
  3. Virtue Theory
  4. Deontology
  5. Utilitarianism

The first three theories are the oldest, and have close ties to religious doctrine. The last two are the most well-known theories these days.

Divine Command Theory

Historically, religions have had a good deal to say about right and wrong. One of the oldest ethical theories is Divine Command Theory, which states:

Moral behaviors are those that are commanded (or willed) by the divine.

This theory was originally proposed in the context of Greek mythology. But since it doesn’t say much about the specific character of the divine, it was adopted by Augustine and some (but not all) modern theologians.

One of the strongest criticisms to Divine Command Theory is the Euthyphro Dilemma, which goes as follows:

  • Is an action ethical because God commands it?
  • Or does God command it because it is ethical?

Clearly, we must affirm one of these options. But which one? Either “horn” of the dilemma extracts painful concessions:

  • On the first option, moral content becomes arbitrary. If God changes his mind about moral facts, our moral universe is turned upside down.
  • On the second, God becomes a middleman who conveys independent ethical facts. Why can’t we simply learn moral truths direct from the source?

These days, most philosophers find Divine Command Theory problematic. But there are other ethical theories available to the faithful.

Natural Law

Another approach to ethical theories, championed by Thomas Aquinas, is Natural Law Theory. Moral truths are grounded as follows:

Moral behaviors are those which promote, and do not detract from, a basic good.

A basic good is injected into human nature by God. Here are three such lists, generated by a Catholic, a Muslim, and a philosopher:

Ethical Theories- Natural Law Basic Goods (7)

Ethical actions promote the basic goods; immoral actions detract from the basic goods. This, incidentally, is why Catholics oppose all forms of birth control: they detract from the basic good of Reproduction.

How did these philosophers generate their lists of basic goods? By observing nature. For example, Life and Reproduction usually make the cut because humans naturally prioritize survival and reproductive success (this is a consequence of natural selection).

However, there is a conceptual difficulty in deriving basic goods from nature. This was clearly expressed by Hume’s Law, also called the is-ought gap: what logical procedure could possibly be used to infer normative statements (an “ought”) from descriptive facts of the words (an “is”)?

Virtue Theories

Unlike its competitors, virtue theory doesn’t spend much time telling you what to do (moral behaviors). Instead, people are the subject of moral truths. Behaviors are only good or evil insofar as they enhance or corrupt a person’s character.

Aristotle presented these ideas in Nichomachean Ethics. There he describes ethical behavior as a way to achieve eudaimonia (human flourishing or “the good life”).

A life of eudaimonia is a life of striving. It’s a life of pushing yourself to your limits, and finding success. A eudaimonistic life will be full of the happiness that comes from achieving something really difficult, rather than just having it handed to you.

Aristotle also believed that moral knowledge is learned not by navel-gazing, but instead comes from social interactions. Specifically, good character is developed by spending time with virtuous people. This theory is where the idea of a role model comes from.

So let’s get down to business. In virtue theory, moral facts are grounded as follows:

Moral people are those who have character; that is, they possess basic virtues.

Aristotle identified twelve basic virtues: Courage, Moderation, Flexibility, Cleanliness, Generosity, Ambition, Patience, Truthfulness, Wittiness, Friendliness, Modesty, and Righteous Indignation. A good person nurtures these virtues.

The Golden Mean provides some insight into how these virtues can be refined over time. A person can respond too strongly with a virtue (excess), or too weakly (deficiency). For example, one must not have too much courage, nor too little:

Ethical Theory- Golden Mean (1)

Virtue ethics is surprisingly robust to philosophical criticism. However, one scientific concern has been gaining traction recently. Empirical research in the field of situational psychology increasingly suggests that there is no such thing as character traits.

Make no mistake, seeing vices and virtues in others is a universal human instinct. But there is no guarantee that mental software works correctly (e.g., see how the brain lies to itself about visual experience). And the fact of the matter is, character information contributes zero predictive power over how a person will respond to a given situation.

Duty Theories

The first ethical theories that isn’t explicitly theistic, Immanuel Kant’s deontological (“knowledge of what is proper”) system purports to result from pure reason.

Moral behaviors are those which obey the categorical imperative.

For Kant, the categorical imperative is a procedure by which a person can discover the rigid contents of the moral universe. He presents four perspectives that independently arrive at these moral truths; the two most influential of which are:

  1. The universalizability principle instructs us to act only if you also desire that your action should become a universal law. Lying is wrong because if lying becomes universalized, meaningful communication becomes impossible.
  2. The principle of humanity instructs us to act in such a way that you treat humanity (both yourself or someone else), always also as an end and never simply as a means. This principle underlies the modern idea of human rights, and is leveraged by Nozick’s brand of libertarianism. 

The categorical imperative promotes a kind of moral absolutism: if actions are right or wrong intrinsically, their moral status is invariant to the consequences of an action. And this inflexibility can produce counterintuitive judgments.

For example, consider a house shielding a Jewish family from the Nazis. If a soldier comes to the door asking about its residents, most of use think it would be morally acceptable to lie. Kant, however, claims that lying is wrong in all situations, even ones such as these.

Consequentialist Theories

Deontological theories are invariant to behavioral outcome. But there are many moral situations where outcome seems to matter. Consider the trolley problem, where a trolley is currently barreling down a track and should kill five people unless diverted. However, on the other track one person has been similarly demobilized:

Ethical Theories- Trolley Problem (1)

Kant would say that pulling the lever is simply murder. That five people die is regrettable, but their death does not incriminate the person at the switch. If the person does divert the trolley, the guilt of the single person’s death is on his head.

However, most people think that the number of deaths – the consequence of an action – matters. Consequentialist theories make this intuition explicit:

Moral behaviors are those that bring the most good to the most people.

Consequentialist theories vary on how they define “the most good” (personal well-being) and “the most people” (societal well-being). 

For example, classical utilitarianism, advocated by Jeremy Bentham and John Stuart Mill, which takes the following stances:

  1. Personal well-being originates from hedonism: actions are moral if they increase pleasure and/or decrease pain.
  2. Societal well-being is taken as the sum total of the well-being of constituent individuals.

Many people condemn utilitarianism for its hedonism (“don’t immoral behaviors often feel pleasurable?”). However, this criticism loses some of its force when you remember to distinguish higher pleasures (eg., aesthetic experience) versus baser pleasures. 

The problem of figuring out societal well-being, how to optimize outcomes for communities, is much more challenging. The repugnant conclusion, aka the mere addition paradox, is a particularly damning criticism. A large society with barely tolerable quality of life (e.g., urban sweat shops) doesn’t feel morally equivalent to happier, smaller societies. 

Ethical Theories- Repugnant Conclusion

Thus, maximizing total well-being may be problematic. But different problems emerge if we instead optimize against average well-being. To this day, designing aggregation functions to compute societal well-being remains an essentially unsolved problem.

Takeaways

Today, we discussed the following theories:

Ethical Theories- Summary

There exist other theories besides these, of course. For example, Hobbes’ contractualism makes important contributions to the conversation. 

To date, no ethical theory has emerged as a clear favorite. A recent survey of professional philosophers reveals considerable support for three of the above theories:

Ethical Theories- Philosopher Opinions

Next time, we will explore whether we should view these normative theories as competitors, or complementary solutions to different concerns. Until then.