Why do people think suicide is morally wrong?

Public surveys show many people view suicide as morally wrong. When you ask them why, they usually refer to the harm caused to the deceased's family and friends, and to the victim themselves. However, a fascinating new study uncovers evidence suggesting that a more important reason people feel suicide is morally wrong is because they see it as tainting the victim's soul. This is the case even for liberal non-religious people. The finding is another example of how our implicit moral judgments are often at odds with our conscious, explicitly stated moral reasoning.

Joshua Rottman and his colleagues presented 174 US participants (114 women; average age 21) online with eight fabricated obituaries that had the appearance of a real obituary published in a paper. The participants were mostly non-religious liberals. Half of them read obituaries about people killed by murder; the other half read obituaries for people killed by suicide. The wording for the obituaries began with a simple statement (e.g. "Louise Parker, who was 68 years old, died on January 11, 2008 due to [suicide/homicide]"). Apart from that single word difference at the end of the opening statement, the remainder of each obituary – a respectful description of the deceased – was the same for participants in the two conditions.

After reading each obituary, the participants were asked to rate the death according to how morally wrong it was; how angry it made them feel; how disgusted it made them feel; how much harm had been done; and whether the victim's soul had been tainted. The order of the questions was randomised. The participants were also asked to state explicitly why each suicide/homicide is morally wrong.

Overall, homicides were judged more morally wrong than suicides, as you'd expect. However, on average the suicides were also rated as morally wrong, consistent with previous public surveys. The most revelatory finding is that the participants' ratings for the moral wrongness of suicides was not correlated with their ratings of the harm caused. Rather, their judgment of moral wrongness was correlated with their ratings of how much the victim's soul was tainted. Consistent with this, the participants' feelings of disgust predicted their ratings for the moral wrongness of suicide, but their feelings of anger did not.

In contrast, to the findings for suicide, ratings for the moral wrongness of homicide were associated with judgments about harm, but not ratings about the tainting of victims' souls. "These results support our principal hypothesis," the researchers said, "suicide, but not homicide, is considered immoral when there are elevated concerns about spiritual taint (impurity), while the same is not true for concerns about harm." Intriguingly, this result was at odds with the participants' explicitly stated reasons for finding suicide morally wrong, which tended to focus on harm caused.

What about the participants' religious and political beliefs? As you might expect, those who were more conservative and religious tended to judge suicide as more morally wrong. But perhaps the most astonishing result from this research is that the link between seeing the victim's soul as tainted and seeing a suicide as morally wrong was just as strong for the non-religious and liberal as for the religious and conservative.

"These results suggest that even if people explicitly deny the existence of religious phenomena, natural tendencies to at least implicitly believe in souls can underlie intuitive moral judgments", the researchers said. The research has some limitations, as the researchers acknowledged – for example, all the participants were from the US, and there's a need to examine other forms of suicide, such as suicide bombers. Also, the causal role of beliefs about purity has not yet been proven.

However, the authors are to be credited for publishing several replications of their main finding (not detailed here). "A greater understanding of the processes that are relevant to the condemnation of suicide victims may prove useful for the millions worldwide who are affected by this widespread tragedy", the researchers concluded.

Further reading

Rottman J, Kelemen D, and Young L (2014). Tainting the soul: Purity concerns predict moral judgments of suicide. Cognition, 130 (2), 217-26 PMID: 24333538