Moral behavior is not what it seems

In a fascinating paper, Crockett et al. (1) investigate the effects of serotonin on moral judgment and behavior by “pitting utilitarian outcomes (e.g., saving five lives) against highly aversive harmful actions (e.g., killing an innocent person)” and conclude that their results imply “that serotonin promotes prosocial behavior by enhancing the aversiveness of harming others” (1). A commentary on this paper claims “a role for serotonin in moral behavior” (2), reinforcing this interpretation of their findings: “The experiment shows that increased serotonin makes individuals less likely to endorse moral scenarios that result in the infliction of personal harm to others” (1).

Unfortunately, this conclusion is problematic. The authors equate harm with violence, placing the harm all on one side of the equation. However, saving five lives, albeit through violence, is also a moral outcome that expresses aversion to harming others; evidently, more others are protected from harm. Moreover, this is a proposition that has both strong intuitive and perhaps even stronger theoretical support (3, 4).

On December 26, 2009, Umar Abdul Mutallab tried to set off a bomb on flight 253 carrying 290 people while it was attempting to land in Detroit. By unhesitatingly attacking and subduing Mutallab, thereby thwarting this attempt and probably saving every life on the plane, Jasper Schuringa became an international hero. The Guardian, a London newspaper, reported on the incident the following day (5):

‘When [it] went off, everybody panicked,’ said Jasper Schuringa, a Dutch film director traveling to the US to visit friends. ‘Then someone screamed, “Fire! Fire!” I saw smoke rising from a seat … I didn't hesitate. I just jumped.’ … Schuringa and the cabin crew then dragged Mutallab, a 23-y-old Nigerian, to the front of the plane, where he was restrained until landing.

Would a serotonin-enhanced Schuringa have “just jumped” (5) or would he have been too averse to the risk of harming Mutallab to have intervened? We will never know, but it is not clear that “enhancing aversion to personally harming others” is something that would promote either moral behavior in the public at large or indeed, harm reduction more generally, unless it was capable of much more nuanced effects than seems evident from the reported research.

Thus, if serotonin affects moral behavior, it does so adversely by impairing moral judgment, subjugating it to emotional instinct. We should be wary of assertions claiming that serotonin has a role in moral judgment; the opposite seems to be the case. It may enhance aversion to violence, but it does not enhance moral behavior; it can increase, rather than diminish, harm to others and bypasses the use of moral reasoning.

Concern with moral behavior is morally bankrupt unless it is also concerned with improving it. The most reliable moral enhancement technologies that we have are education, parental and peer influence, and example and moral reasoning. We would welcome smart pills (or perhaps good pills) that could improve on these technologies, but they seem as far off as ever.