IKON IMAGES / CORBISOne of our favorite scientific studies of the past few years is a laboratory assessment of how people react to strangers, conducted by Alex Todorov and colleagues at Princeton.1 They presented subjects with pictures of faces—many faces—that they had never seen before. All of the faces were intended to have no discernable expression, that is, they wore neutral expressions. The subjects were asked to rate how trustworthy they thought each face was based on a gut reaction. Naturally, each subject thought that some of the faces were more trustworthy-looking, some were less trustworthy-looking, and some were neutral. At the same time, the response of each subject’s amygdala—a deep brain structure—was measured using functional magnetic resonance imaging (fMRI).
The measured responses showed some relationship with the judgments the subjects made about the faces. Specifically, the amygdala responses were greatest to faces judged to be the most untrustworthy. As cool as that is, it was not the most interesting finding.
From the many and varied opinions of the individuals ranking the faces of strangers, Todorov and colleagues computed a mean trustworthiness rating for each face. The faces were then ordered in terms of what the group thought. This was a group rule; no one individual who was studied could possibly have known what this rule was. Yet, remarkably, the mean response of the amygdala across all subjects was positively correlated with the mean trustworthy ratings for the group of subjects. This extraordinary finding tells ...
