“I’m a superstitious man, and if some unlucky accident should befall Michael, if he is to be shot in the head by a police officer, or be found hung dead in a jail cell… or if he should be struck by a bolt of lightning, then I’m going to blame some of the people in this room, and then I do not forgive.”
–Don Corleone, The Godfather
Across cultures, humans enthusiastically punish those who harm the self, one’s kin, or members of the broader social group, even at great personal cost. This willingness to punish likely confers adaptive benefits to the self and also helps groups coordinate and cooperate. If people know they might be punished, they will avoid transgressions in general, and perhaps especially avoid transgressions against those with reputations as punishers. Don Corleone takes his vengeful reputation a step further and threatens punishment even if an “unlucky accident” should befall his son. Holding individuals morally culpable even for harmful accidents likely reduces careless harmful behavior, which could explain why society punishes harmful acts of “negligence.” Thus, the human tendency to identify morally culpable agents — even when the existence of one is dubious — might be evolutionarily advantageous.
To many scholars and everyday people alike, moral responsibility is predicated on free will. The existence of free will, however, is a contentious and persistent philosophical dispute. Other similar debates — such as whether a God exists — have been mostly resolved in recent decades as scholars have been forced by science to reject the supernatural. For religious belief, scholars have now turned to discussing and investigating the causes. Why did religions evolve? What situational features increase or decrease religious belief? But until very recently, no analogous exploration of the causes of free will belief has emerged.
Though scholars have not agreed on the necessary capacities for human free will, and everyday people do not appear to have a coherent conception of free will,1 belief in free will appears to be a near cultural universal.2 And this belief appears to be very important to people. A google search of the phrase “no free will” will reveal images of puppets, chains, and robots, and discussions of how abandoning the concept of free will could turn everyone into criminals (because nobody would feel responsible) and destroy our ability to punish (because the punishment would no longer be justified).
That humans nearly universally accept the existence of a concept that has no clear definition — and with great fervor — suggests that this concept was important for human flourishing, and that it was likely selected for in some capacity. In other words, free will belief, like religious belief, likely evolved because such beliefs were advantageous for regulating social behavior and thus for promoting the survival and expansion of social groups (increasing the inclusive fitness of the members of the group).
So, why did free will belief evolve?
Both scholars and everyday people seem to agree that free will (whatever it is) is a prerequisite for moral responsibility (though note, among philosophers, there are numerous definitions and camps regarding how free will and moral responsibility are linked). This suggests that a crucial function of free will beliefs is the promotion of holding others morally responsible. And research supports this. Specifically, when people are exposed to another’s harmful behavior, they increase their broad beliefs in the human capacity for free action.3 Thus, believing in free will might facilitate the ability of individuals to punish harmful members of the social group ruthlessly.
But recent research suggests that free will is about more than just punishment. People might seek morally culpable agents not only when desiring to punish, but also when desiring to praise.4 A series of studies by Clark and colleagues (2018) found that, whereas people generally attributed more free will to morally bad actions than to morally good actions, they attributed more free will to morally good actions than morally neutral ones. Moreover, whereas free will judgments for morally bad actions were primarily driven by affective desires to punish, free will judgments for morally good actions were sensitive to a variety of characteristics of the behavior.
In studies 2a-2b, participants were randomly assigned to read about a morally good behavior or a comparable morally bad behavior. Participants then responded to a variety of questions about the behavior, rated the extent to which the behavior was performed of the actor’s own free will, and reported their broad beliefs in human free will. For participants who read about the immoral action, higher free will attributions and higher broad beliefs in human free will were predicted by higher perceptions of the severity of the infraction, more moral outrage, and stronger desires to punish. Similarly, among participants who read about the morally good action, higher free will attributions and stronger broad beliefs in human free will were predicted by greater perceived generosity of the action, feelings of being morally uplifted, and stronger desires to reward. However, unlike free will judgments regarding the immoral action, perceptions that the morally good action was atypical or counter-normative and that the action required willpower predicted stronger free will judgments.
If we view free will judgments through the lens of adaptive benefits, these results make sense. First, punishing harmful behaviors is likely more important for survival than rewarding good ones, hence the lower threshold of perceiving harmful actions as freely performed (regardless of other situational features). Second, as noted before, punishing even negligent harmful behaviors, including those that are normative or performed without intention can reduce careless harms. In contrast, because people already are inclined to behave in normative ways, rewarding such behaviors would likely do little to increase them.
Based on these results, we suspect people might attribute more free will to actors and believe more that certain behaviors result from free will precisely when doing so would be advantageous to the self and social group. There are a few main evolutionary challenges to consider. First, one must praise the good and condemn the bad so as to promote morally good behaviors and discourage morally bad ones among members of one’s social group. But second, one must praise and condemn effectively so as to not waste resources praising and condemning behaviors that cannot be shaped by praise and condemnation.
So, for example, people might not ascribe free will to infants, severe schizophrenics, many animals, and any others who are immune to moral judgment in the sense that their behavior would not change in response to blame, shame, or reputation damage. Perceiving such agents as morally culpable would be a waste of one’s time and energy. Moral agency should be reserved for those whose behavior can be manipulated by moral judgment. In other words, free will judgments might have evolved to track potential moral agents’ responsiveness to judgment. If an agent who causes harm would be deterred from causing harm in the future if one morally blamed and shamed them, then one might say that agent has free will and, thus, is a morally culpable agent. Ironically then, people might ascribe free will to an agent not when an agent is perceived to have great internal control, but rather when an agent is perceived to be externally controllable by moral judgment.
Of course, research into the origins of free will belief is only in its infancy. More work is needed to understand when and why people ascribe free will to others and to test and challenge our evolutionary hypothesis forwarded here. We suspect, however, moral condemnations work best when the subject is responsive to them and can subsequently change his or her behavior, and free will judgments might have evolved to make this distinction.