Why humans evolved to feel shame

"What is key," Daniel Sznycer says, "is that life in our ancestors' world selected for a neural program—shame—that today makes you care about how much others value you." (Credit: ▲ r n o/Flickr)

Feelings of shame are universal in all cultures, and new research could explain why. Studies in the US, India, and Israel suggest that shame—like pain—evolved as a defense.

“The function of pain is to prevent us from damaging our own tissue,” says Daniel Sznycer, lead author of the paper in the Proceedings of the National Academy of Sciences. “The function of shame is to prevent us from damaging our social relationships, or to motivate us to repair them.”

“Our ancestors lived in small, cooperative social groups that lived by hunting and gathering,” says John Tooby, a professor of anthropology at UC Santa Barbara and a coauthor of the paper. “In this world, your life depended on others valuing you enough to give you and your children food, protection, and care.

“The more you are valued by the individuals with whom you live—as a cooperative partner, potential mate, skilled hunter, formidable ally, trustworthy friend, helpful relative, dangerous enemy—the more weight they will put on your welfare in making decisions. You will be helped more and harmed less.”

The flip side: Being devalued by others

“When people devalue you, they put less weight on your welfare. They help you less and harm you more,” says Leda Cosmides, a professor of psychology and also an author of the paper. “This makes any information that would lead others to devalue you a threat to your welfare.”

The authors call this theory, which brings together the views of a number of evolutionary researchers, “the information threat theory of shame.”

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“What is key,” Sznycer says, “is that life in our ancestors’ world selected for a neural program—shame—that today makes you care about how much others value you, and motivates you to avoid or conceal things that would trigger negative reevaluations of you by others.”

The authors argue that shame is necessary to successfully navigate the landscape of human social life.

As Tooby put it, “the shame system is designed to give others some vote in what behavior you end up choosing.”

How much shame would you feel?

To test the idea, the researchers created two dozen brief fictional scenarios depicting behaviors or traits that were expected, on evolutionary grounds, to lead to devaluation: stinginess, infidelity, and physical weakness, among others.

They ran these on populations in the US, India, and Israel. One group of participants was asked to report, for each scenario, how negatively they would view another person if those things were true of that person. A different group of participants was asked how much shame they would feel if those things were true of themselves.

“We observed a surprisingly close match between the negative reactions to people who commit each of these acts—that is, the magnitudes of devaluation—and the intensities of shame felt by individuals imagining that they would commit those acts,” Cosmides says.

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“This is just what you would expect of a defensive system engineered to balance the competing demands of effectiveness and economy,” Sznycer points out.

Moreover, this close match appears to be a feature specifically of shame.

“Follow-up studies showed that other emotions that co-activate with shame, such as sadness and anxiety, do not track audience devaluation like shame does. So it appears that it’s shame in particular, and not ‘negative’ emotions in general, that is tasked with dealing with the threat of devaluation,” Cosmides says.

Researchers from the University of Amsterdam, University of the Negev, and the Interdisciplinary Center Herzliya in Israel collaborated on the study.

Source: UC Santa Barbara