Ulterior Motives

How goals, both seen and unseen, drive behavior

Art Markman is a cognitive scientist at the University of Texas whose research spans a range of topics in the way people think. See full bio

January 1, 2009, Personality

Cleanliness is next to Godliness, or at least morality.

Moral failings really are disgusting.

In the past few weeks, the news has been full of stories about Bernard Madoff, who spent years cheating business associates, friends, charities and investors out of billions of dollars in an elaborate scam. I must admit that when I heard about some of the charities that lost huge portions of their endowments to him, I experienced a feeling of revulsion and disgust.

Recent research suggests that there is a deep connection between judgments of moral failure and disgust. Perhaps more interestingly, there is also a deep connection between judgments of moral correctness and cleanliness.

Disgusting trash In an August 2008 paper in Personality and Social Psychology Bulletin, Simone Schnall, Jonathan Haidt, Gerry Clore, and Alexander Jordan had people make judgments about the acceptability of a variety of moral issues such as whether first cousins should be allowed to marry. Moral judgments of this type were selected, because they tend to make people feel some amount of disgust or revulsion. Some people made these judgments in the presence of a disgusting odor coming from a nearby trash bag. Others made the same judgments without the disgusting odor. People who made the judgments near the odor found the moral issues much less acceptable than people who made the judgments without the odor, suggesting that the physical disgust heightened the sense of moral disgust.

Interestingly, the opposite also seems to be true. In a December 2008 paper in Psychological Science, Simone Schnall, Jennifer Benton, and Sophie Harvey looked at the relationship between cleanliness and moral judgment. In this study, people judged whether a variety of moral scenarios were acceptable or unacceptable. The scenarios were things like the acceptability of keeping money from a found wallet or putting false information on a resume. Some people made these judgments immediately after washing their hands to sit in a room that was supposed to be kept tidy. Others had not just washed their hands. People who had just washed found the scenarios more acceptable overall than people who had not washed their hands, suggesting that physical cleanliness led to judgments of moral acceptability.

These results suggest that our sense of moral outrage really creates a sense of physical disgust. Good moral acts create a sense of cleanliness and purity. When we want to judge how strongly we feel about a moral action, we look to the state of our bodies for an answer. So, when you say that an action like Bernard Madoff's is revolting, you really mean it.