Humans judge a group of other people in half a second

A new study from the University of California Los Angeles (UCLA) shows that we form assumptions about a group of people in the amount of time it takes to blink our eyes. In just a half a second, people discern the number of men versus women in a group and decide whether the group is threatening or not.

According to the researchers, groups tend to feel more threatening to us than a single person. They say that how many people are in the group and also the sex ratio of the group make a difference in our split second assessment.

“These judgments impact whether we think groups are hostile or hospitable,” explained lead author Nicholas Alt. “For example, if you enter a public park, you rapidly notice the number of men and women. And, if there are only men or a majority are men, you would judge the group as threatening.”

Studies in vision science and social psychology have shown that humans can perceive a person’s social category, emotional state, and personality traits just by glimpsing at the individual’s face. The research team set out to determine if we can decipher groups this quickly as well.

The experts developed a series of three studies to examine how quickly and accurately people detected differences in groups. Overall, the participants could identify a group’s ratio of men to women in 500 milliseconds and judged groups as more threatening as the ratio of men to women increased.

Now that they have demonstrated how fast people can extract social category data from a group of faces, the team plans to investigate ways to potentially manipulate a person’s perception of groups. They will also analyze whether masculinity and femininity are perceived at rapid speed through visual cues, and the effect that this may have on social evaluative judgments.

The study is published in the journal Social Psychological and Personality Science.

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By Chrissy Sexton, Earth.com Staff Writer