Belief that the world is dangerous predicts greater accuracy among women in discriminating real and fake smiles, according to research published in the journal Evolutionary Behavioral Sciences.

“I have always been interested in how information communicated by faces can assist humans in navigating problems related to survival and reproduction,” said study author Donald Sacco, a professor of psychology at The University of Southern Mississippi.

“Given the complex information communicated by faces (motives, emotions, personality) and our history of face-to-face social interactions, a high degree of sensitivity to information from faces could be a fruitful way humans identified cooperative conspecifics to affiliate with and exploitive conspecifics to avoid.”

The study of 62 men and 87 women examined whether the participants believed the world to be a dangerous place and tested how well they could discriminate between a genuine and fake smile.

The researchers found that women who viewed the world as a more threatening place tended to be better at determining the authenticity of a man’s smile.

In other words, women — but not men — who agreed with statements such as “Things are getting so bad, even a decent law-abiding person who takes sensible precautions can still become a victim of violence and crime” were more likely to be able to discriminate between a genuine and fake smile.

“Our results indicate that at least for women, chronic and salient beliefs that one’s environment communicates a high degree of interpersonal threat predicts a greater capacity to use facial affect cues to identify safe interaction partners to affiliate with and exploitive conspecifics to avoid,” Sacco told PsyPost. “Thus, people tend to have elevated sensitivities to relevant information about social targets that would facilitate their more chronically activated goals.”

However, the findings do include some caveats.

“While this research documents heightened perceptual accuracy, we do not yet know whether and how this relates to actual behavior,” Sacco explained.

“Future research should determine whether this enhanced accuracy for women with higher dangerous world beliefs translates to differences in actual approach and avoidance behavior with respect to targets displaying genuine versus disingenuous facial affect, respectively.”

“Humans have had a long time to become experts at extracting valuable information from others’ faces,” Sacco added. “As such, most humans have inherited a highly sensitive perceptual system for extracting this information so as to best solve problems related to survival and reproduction.”

The study, “Women’s dangerous world beliefs predict more accurate discrimination of affiliative facial cues“, was co-authored by Mitch Brown, Christopher J. N. Lustgraaf, and Steven G. Young.