For social animals like humans, the health cost of loner-dom can be high—depression, high blood pressure, and an increase in stress hormones have all been linked to a lack of social connection. Previous research has also shown that when people are feeling lonely, they are better at cooperating and are more sensitive to emotions and social cues. But a new, small, weird study published in Psychological Science suggests that the isolated may cast about too wildly for companionship, leaving them with a lowered ability to tell if a face is alive or not.
Researchers at Dartmouth College and Harvard University showed a group of 30 students a series of 90 faces. Some of the faces were human, some were inanimate (a doll or a statue), and the rest were morphs of human and non-human faces, on a continuum of 0 to 100 percent human. The participants categorized each face as “animate” or “inanimate,” then, after the facial recognition task, filled out a questionnaire designed to measure their need for social connection.
On average, people started classifying the faces as “animate” when they were 69 percent human. That’s pretty normal—prior studies have shown that a face needs to have more than 50 percent human features for people to see it as alive. But the people who were really jonesing for social connection tended to have a lower threshold.