How do we decide whether to trust somebody?

An unusual new study of college students’ interactions with a robot has shed light on why we intuitively trust some people and distrust others. While many people assume that behaviors like avoiding eye contact and fidgeting are signals that a person is being dishonest, scientists have found that no single gesture or expression consistently predicts trustworthiness.

But researchers from Northeastern University, the Massachusetts Institute of Technology and Cornell recently identified four distinct behaviors that, together, appear to warn our brains that a person can’t be trusted.