Stanford, California - Culture may play a key role in whether people "like" or "don't like" others, new Stanford research shows.
The differences are notable among Americans of European descent compared with people of Chinese origin.
"People respond more favorably to others who express the distinct kinds of positive emotions valued by their culture," said Jeanne Tsai, a Stanford associate professor of psychology. Tsai directs the Culture and Emotion Lab at Stanford and is one of the lead authors on the study, which was published in the Social Cognitive and Affective Neuroscience journal.
Tsai explained that people tend to immediately like and want to approach some people, but not others. "But the reasons for these fast reactions are unclear," she said, suggesting that culture plays a role.
The study involved 19 European American and 19 Chinese female undergraduate and graduate students (18-28 years old) from universities in the San Francisco Bay Area who participated in a study on rating faces. The students viewed faces that differed by expression (excited versus calm), ethnicity (white, Asian) and gender (male, female) while their brains were scanned.
Tsai said the research combines cultural psychology with neuroimaging, and is part of an emerging field of "cultural neuroscience." And so, the researchers used functional magnetic resonance imaging (FMRI) to shed light on the "depth" of culture's influence on preferences, she noted. This allowed the researchers to see neural responses to positive expressions in both European American and Chinese students.
In the study, Tsai and her colleagues examined whether cultural values could drive neural responses and preferences for different positive facial expressions – like excited versus calm faces. They reasoned that subjects' "ideal affect," or culturally valued emotional states, would shape their brain and behavioral responses to different positive expressions.
"Within cultures, European Americans responded similarly to excited and calm faces, but Chinese showed greater activity in the ventral striatum in response to calm versus excited expressions," Tsai said.
The ventral striatum is part of the brain involved in emotional responses, particularly those related to the anticipation of pleasure. "This pattern held regardless of the ethnicity or gender of the face," Tsai added.
These differences in neural responses mirrored subjects' ideal affect, since European Americans tend to value excitement and calm to similar degrees, but Chinese generally valued calm more than excitement.
In fact, Tsai explained, activity in the ventral striatum predicted peoples' preferences for excited versus calm faces many months later.
"Our findings suggest not only that different cultures value distinct positive expressions, but further that these differences are visible in deep brain circuits implicated in reward and affect, and predict their later preferences for social partners," she said.
For example, Chinese might avoid people who express more excitement than calm, Tsai wrote. "People prefer and value those who express the positive emotions most valued by their own culture."
"It's interesting that in this case, people's expressions have more of an impact than their ethnicity or gender," Tsai said.
"When we meet other people, we may automatically like or dislike them, but we may not necessarily know why. Our research suggests that culture – through ideal affect – plays an important role, which could have implications for who we choose to partner with and promote in the future," Tsai said.
Tsai's co-authors include Stanford Associate Professor of Psychology Brian Knutson; Stanford psychology doctoral student Bokyung Park; Stanford psychology researcher Elizabeth Blevins; and Louise Chim, who received her doctorate at Stanford and is now an assistant teaching professor in psychology at the University of Victoria in Canada.