Psychologist Paula Niedenthal was rereading The Little House on the Prairie series five years ago when a question came to mind: On the U.S.'s plains in the 1800s, how did the mix of cultures affect how people expressed their emotions? From demonstrative Italians to reticent Swedes, a variety of immigrant groups had to communicate during farming and trading. She wondered whether the long history of migration in the nation has influenced the way we show our feelings.
In 2011 Niedenthal found the data she needed to answer that question—the number of cultures migrating to various countries during the past 500 years—in a paper written by two economists at Brown University. Using those data, Niedenthal and her graduate students at the University of Wisconsin–Madison recently published two papers demonstrating that people from heterogeneous cultures—those with more historical immigration—display more easily recognized emotions than those from homogeneous cultures.
“If you share language and culture, you don't need to be emotionally expressive,” Niedenthal says. If you do not have that common background, you would want your emotions to be obvious and get your point across.
In one of the papers to come out of Niedenthal's group, published in 2015 in the Proceedings of the National Academy of Sciences USA, first author Magdalena Rychlowska and her co-authors had 726 people from nine countries complete a questionnaire about how they react to different facial expressions. The researchers found that those from more historically heterogeneous cultures tend to see a smile as a good reason to be friendly or get close to someone. Those from homogeneous cultures, however, more often saw a smile as a way to demonstrate superiority. “Smiles are basically like languages—you use them in different ways,” says Rychlowska, now at Cardiff University in Wales.
Expanding on that research, Adrienne Wood, a current Ph.D. candidate in Niedenthal's lab, gathered existing data on emotion recognition from 92 papers representing 82 cultures. She looked at how often subjects attributed the correct emotion to a photograph, video or audio recording and compared that with the historical heterogeneity in the expresser's country. She found that people from cultures with higher rates of immigration display more recognizable facial expressions and vocal cues. “Cultures evolve to address the particular challenges of their social and ecological environments,” says Wood, whose study was published this past January in Emotion.
The researchers hope to investigate more census data soon, which may reveal how long it takes a heterogeneous population of people to shift the way they emote. “A long history of migration changes the whole culture,” Niedenthal says.