SWAG: The Aversion to Harm Others

Every Wednesday afternoon, I gather with a bunch of faculty and graduate students at the University of Illinois to discuss a journal article about social psychology, and to eat a snack. This blog post reflects the discussion we had during this week's seminar affectionately called Social Wednesdays and Grub (SWAG).

This week in SWAG we read a paper on committing harmful actions by Fiery Cushman and colleagues (2012), who may have the most fantastic name in all of the academic world. Cushman was curious about why people are averse to committing harmful acts on others.



There is a growing body of research and thought that centers around the idea that human beings have evolved to be averse to harming others. As social living mammals, harming members of one's social group would be a sure way to become ostracized from group activities, and so, it is reasonable to assume that harming others is aversive. Some initial evidence supports this theory: For instance, soldiers who are trained in combat report that they commonly and purposely aim their weapons away from human targets.

So, is there an aversion to committing harmful acts?

Two studies were conducted to test this prediction. In the first study participants were asked to perform a difficult arithmetic task--an aversive or threatening state of social evaluation--and were then subsequently asked to imagine being onboard a sinking lifeboat. In the scenario, the lifeboat may sink (killing everyone) unless the participant pushes one of the passengers (leaning over the side) overboard. Participants who showed more physiological signs of aversive threat, measured in terms of total peripheral resistance--a measure the rigidity of one's blood vessels, which is related to reductions in blood flowing to the extremities of the body--were more averse to pushing the passenger overboard.

In the second study, participants were asked to either perform or witness an act of harm on another person, or to engage in a physically similar action. For example, either actually mimicking cutting another's throat, watching someone perform the act, or cutting a cardboard loaf of bread. When actually mimicking the harmful act, participants showed increased total peripheral resistance--indicating more experienced aversive threat--then when watching another commit the act, or in committing a physically similar motion. The authors reasoned that people have learned aversions to committing acts that harm others so that (1) unrelated aversive threat states carry with them an aversion toward committing violence and (2) even simply pantomiming harm can create aversive threat reactions.

In terms of overall impressions, I think our SWAG group enjoyed the design of Study 2 in particular, which suggested that performing harmful acts is a learned aversion rather than caused by an empathic response to others' suffering. SWAG did wonder if aversive reactions to harm are lessened by experiences of anger, or by focusing on the specific motions themselves rather than the harm they could cause?

Cushman F, Gray K, Gaffey A, & Mendes WB (2012). Simulating murder: the aversion to harmful action. Emotion (Washington, D.C.), 12 (1), 2-7 PMID: 21910540