If you ask a kid what it means to be male or female, you’ll likely get a pretty stereo­typ­ical response. Boys, kids tend to think, are inher­ently inter­ested in boy-​​like things—trucks, base­ball, and con­struc­tion work—while girls are inher­ently inter­ested in dolls, dress-​​up, and tea par­ties. Boys like to build things and go fishing and want to be foot­ball players when they grow up. Girls like to sew, wear makeup, and want to be bal­lerinas. For the young exam­inee, the behav­ioral ten­den­cies of boys and girls are just as fun­da­mental as their phys­ical attributes.

Most research has found that this stereo­typ­ical, or “essen­tialist,” thinking tends to fade as we get older. According to asso­ciate pro­fessor of psy­chology John Coley, the aca­d­emic lit­er­a­ture has sug­gested that by the time we’re in ele­men­tary school we start to see envi­ron­ment as playing a large role in the man­i­fes­ta­tion of gender roles. We learn that girls aren’t inher­ently more inclined to be teachers and nurses, but that our envi­ron­ment and our expe­ri­ences urge us into such gender-​​normal behaviors.

But new research from Coley and R. Cole Eidson, a doc­toral can­di­date in his Cat­e­go­riza­tion and Rea­soning Lab at North­eastern, sug­gests that we retain some of our child­like, essentialist-​​thinking into adult­hood. In a paper pub­lished ear­lier this year in the Journal of Cog­ni­tion and Devel­op­ment, the duo repeated ear­lier studies of chil­dren using a group of under­grad­uate stu­dents, but they added a twist.

Eidson explained that if you could strip away an adult’s years of cul­tural learning—in which they col­lect a better under­standing of people’s indi­vid­u­ality and how they think and behave—“then you might still find essen­tialist thinking lurking beneath the sur­face.” To accom­plish this, they gave the study’s par­tic­i­pants a time constraint.

First, they pre­sented the 36 male and 33 female par­tic­i­pants with four char­ac­ters: a girl raised by only women, a girl raised by only men, a boy raised by only women, and a boy raised by only men. Then, just as with the ear­lier studies on chil­dren, they asked the par­tic­i­pants how the indi­vidual would behave in a par­tic­ular sit­u­a­tion or what kinds of phys­ical attrib­utes the person would have as an adult. But unlike the ear­lier studies, Eidson and Coley split their par­tic­i­pants into two groups with two dif­ferent direc­tives. Half of them had to wait 10 sec­onds before making their deci­sion about the char­acter while the other half had to make a snap judg­ment, answering the ques­tion in less than two seconds.

The con­straint made a sig­nif­i­cant dif­fer­ence. Those who had to reply quickly tended to respond with more stereo­typ­ical answers, just as a pre-​​elementary-​​school child might do. The par­tic­i­pants who had more time to con­sider their replies tended to respond with more socially-​​acceptable answers.

This work shows that essen­tialist thinking is auto­matic and deeply-​​rooted, but that people can over­come this bias given time and cog­ni­tive resources,” Coley said.

The researchers found that male par­tic­i­pants tended to par­take in more essen­tialist thinking than their female coun­ter­parts, regard­less of the group to which they were assigned. They also found that all par­tic­i­pants, regard­less of con­di­tion or their own gender, held stronger stereo­types about males than about females. “People,” Eidson explained, “are less willing to accept vio­la­tions of the male gender role than of the female gender role.”

Coley and Eidson can only spec­u­late on why this might be the case, but per­haps, Coley said, it has some­thing to do with the fact that female gender roles have under­gone a deter­mined shift over the past century.

This research con­tinues the work being done in Coley’s lab exam­ining the way humans cat­e­go­rize their world. But this study is among the first to look at the cog­ni­tive processes under­lying the way we cat­e­go­rize our fellow humans based on gender.

The work, Eidson said, has impli­ca­tions for dealing with social phe­nomena such as prej­u­dice and stereo­typing. If we believe that dif­ferent groups have dif­ferent inherent prop­er­ties and we start assigning values to those prop­er­ties, “then really quickly you can move into a place where one group is less desir­able than another,” he said. “Even adults are still doing this, it’s just under the sur­face. Under­standing that may give you some kind of inroad to dealing with those kinds of issues.”