The Velocity of Trust

Back in the early 1970s, Americans declared unambiguously that the most trusted person in the land was Walter Cronkite. Not a single politician in the headline-grabbing opinion poll came even close to the longtime CBS news anchor for easing citizens’ minds.

That was a different time, of course. We were mired in an unwinnable war, and politicians weren’t trusted as they are today. It was way before journalists were recognized as traitors. Back then, Americans really had issues to worry about, and they detected something comforting in the nightly appearance of that flickering, avuncular face.

Was it his eyes? His jowls? His receding hairline? Or was it something more nuanced about his demeanor that led to that collective judgment? We don’t really know what specific features captured Americans’ trust, but the event belongs in a long tradition of looking for deeper meaning in people’s appearances. Two centuries earlier, the European intellectual classes were abuzz over physiognomy, the science of reading personality traits in facial features. It was easy, for example, to spot someone of rock-solid character: His eyebrows would invariably be close to his eyes.

Physiognomy has long since been tossed on the trash heap of pseudoscience, but true scientists are reluctant to give up entirely on the idea that impressions have some potency—and perhaps validity. After all, we know that attractive people land better jobs, attract better mates—all in all do better in life. And baby-faced people get lighter jail sentences and other unearned advantages. We vote for candidates we perceive as “competent.”

Psychologists at Princeton University have been studying first impressions in the laboratory, to see just how quickly people are able to judge a stranger from his or her face, and how robust those impressions are. In a series of experiments, Janine Willis and Alexander Todorov had participants look at photographs of unfamiliar faces and judge their character. Sometimes they were exposed to the photographs for a full second or half a second, but other times they were asked to make judgments based on a mere 1/10th of a second viewing. That’s much briefer than a finger snap.

The participants judged the strangers on five traits: attractiveness, likeability, competence, trustworthiness, and aggressiveness. Attractiveness is obviously not a character trait; it was thrown in there as a kind of benchmark for how quickly people process facial information. The others—especially trustworthiness, competence, and aggressiveness—are traits that are crucial to everything from relationships to financial decisions.

Before running the experiment, the scientists had tested the photographs on a large sample of viewers without time constraints. This was the equivalent of the opinion polling that identified Cronkite as trustworthy. These collected opinions became the gold standard for trustworthy faces, competent faces, and so forth.

When the psychologists put the participants on the clock, they found that even the briefest exposure—a 1/10th of a second peek—was enough for them to accurately detect the five traits. As they report in the July issue of the journal Psychological Science, increasing the time, even to a full second, did not significantly improve the judgments. What the additional time did do, however, was make the participants more confident in their instantaneous impressions. That is, given more time to “study” the strangers’ faces, they didn’t waffle at all on their first impressions. They solidified them.

Willis and Todorov were surprised by one finding. They expected the instantaneous judgments of attractiveness to be the most uniform and reliable, simply because attractiveness doesn’t require any interpretation. But they were wrong. In fact, the quickest, most accurate impressions were of trustworthiness. In retrospect, the scientists say, this should not be all that surprising: Fleet judgments of trustworthiness would have been crucial to survival when we were evolving on the savannahs eons ago, so the skill probably got wired into our biology. Indeed, brain studies indicate that judging trustworthiness is a spontaneous, automatic process of the brain’s amygdala, a region known to be involved in sensing danger in the world. The researchers didn’t test anything faster than 1/10th of a second, but that could actually be a leisurely pace for such life-saving decisions: “Maybe,” they speculate, “as soon as a face is there, you know whether to trust it.”

We still don’t know exactly why Americans chose to put their trust in an aging newsman back in 1972. Or for that matter, how people sort their friends and enemies today. But what the science does say clearly is that these crucial impressions are quick, effortless and, well, trustworthy.

For more insights into human nature, visit the Association for Psychological Science website at www.psychologicalscience.org/onlyhuman.