We may trust a stranger who resembles someone we knew

As per the study, people will mostly keep faith in an unknown person who appears to be trustworthy

Whether or not we trust a stranger may depend on their resemblance to other people we’ve previously known, a new study suggests. The results show that we trust strangers resembling individuals we believe to be trustworthy more; by contrast, we trust those similar to others we believe to be untrustworthy less.

“Our study reveals that strangers are distrusted even when they only minimally resemble someone previously associated with immoral behaviour,” explains lead author Oriel Feldman Hall, who led research as a postdoctoral fellow at New York University and is now an assistant professor in Brown University’s cognitive, linguistic, and psychological sciences department.

“We make decisions about a stranger’s reputation without any direct or explicit information about them based on their similarity to others we’ve encountered, even when we’re unaware of this resemblance,” adds senior author Elizabeth Phelps, a professor in the psychology department at NYU. “This shows our brains deploy a learning mechanism in which moral information encoded from past experiences guides future choices.”

To explore this, the researchers conducted a series of experiments centering on a trust game in which participants make a series of decisions about their partners’ trustworthiness-in this case, deciding whether to entrust their money with three different players who were represented by facial images.

In a second task, researchers asked the same subjects to select new partners for another game. Unbeknownst to the subjects, however, the face of each potential new partner was morphed, to varying degrees, with one of the three original players so the new partners bore some physical resemblance to the previous ones.

Moreover, these decisions to trust or distrust strangers uncovered an interesting and sophisticated gradient: trust steadily increased the more the stranger looked like the trustworthy partner from the previous experiment and steadily decreased the more the stranger looked like the untrustworthy one.