By Adrienne Wood

Imagine yourself as a 19th century American pioneer who has just moved your family to Nebraska to start a farm. The land is only recently settled by European Americans, so your survival depends on your ability to cooperate with your few neighbors, who may be Austrians, Bohemians, Norwegians, Germans, Russians, or recently emancipated African Americans from the South. Without a well-established social structure, shared norms, reliable social institutions, and perhaps even a common language, you must somehow establish trust and communicate intentions with your neighbors.

Fortunately, you and your neighbors have one language in common—emotional expressions. Over time you and your neighbors may start to produce bigger and clearer facial and body expressions in order to compensate for a lack of common norms and language. Within this highly heterogeneous cultural context, a norm of greater emotional expressivity may develop, and continue to persist across generations. This is the hypothesis that sparked several recent studies my advisor, Dr. Paula Niedenthal at the University of Wisconsin – Madison, our collaborators, and I have completed.

Facial expressions in cultural contexts

Since people from very different cultures can recognize each other’s facial expressions of emotion at better than chance accuracy, facial expressions may be a particularly valuable tool for communication in situations where people have very little in common culturally and linguistically, as in 19th century Nebraska. In trying to interact with your neighbor who does not speak the same language, you may be more expressive with your face, body, and the nonverbal components of your voice that communicate emotion. Then your kids and grandkids, and your neighbors’ kids and grandkids, would grow up in this expressive culture, which will be perpetuated even after the original driving force—cultural heterogeneity—decreases over time. Thus, in heterogeneous cultures, an emotion expression norm is fostered that involves open expressivity.

Cultures whose populations have stayed put for hundreds of years and are therefore relatively more homogeneous, such as Japan and Norway, have shared cultural knowledge, norms, and language, and so can rely on more than clear, big expressions of emotion. Because stable, homogeneous cultures have a common background, we might even expect them to display more idiosyncratic facial gestures that are not recognizable to people from other cultures: in Tibet, for instance, people sometimes greet each other by sticking their tongues out. It is worth noting that the labels heterogeneous and homogeneous do not imply that one type of culture is better than the other; they simply describe the historical makeup of a nation’s population. Historical heterogeneity reflects long-term patterns in immigration rather than more modern trends in globalization and ethnic fractionalization because something as subtle as the emotion expression norms of a culture should take time to emerge.

My lab started pursuing the notion that long-term historical migration patterns might shape emotion expressions when we learned that economists Louis Putterman and David Weil (2010) at Brown University developed a quantitative measure of historical heterogeneity by analyzing genetic and archival data from around the world. Their metric of heterogeneity is a count of how many other countries contributed to the present-day populations of 165 nations over the last 500 years (see the map below). For example, the United States has the highest score with 83 source countries—meaning immigrants have come to the U.S. over the last 500 years from 82 different countries (plus 1 for Native Americans)—Israel has a mid-range score of 22, and Indonesia has a highly homogeneous score of 2.

Heterogeneous countries are more emotionally expressive

Last year Paula Niedenthal, Magdalena Rychlowska, and their coauthors tested the hypothesis that cultures’ heterogeneity scores and emotional expressivity should be related. Using Putterman and Weil’s heterogeneity metric, they found that people from heterogeneous countries are more likely to endorse the rule that emotions should be openly expressed as felt, while people from relatively more homogeneous countries say it is not always appropriate to express your emotions. This finding, published in the Proceedings of the National Academy of Sciences, was a promising demonstration that historical heterogeneity may shape cultures’ emotional expressivity dialects.

Expressions of heterogeneous cultures are more universally recognizable

Since heterogeneous societies encourage bigger facial expressions that are perhaps less idiosyncratic than those of homogeneous, older societies, we wondered if the expressions of heterogeneous cultures might also be more universally recognizable. After all, the proposed function of greater emotional expressivity in a heterogeneous context is to more clearly communicate feelings and intentions to people who do not share the same background.

To test this possibility, we examined 92 previous psychology studies in which people from one culture were asked to identify the emotions expressed in photos or videos of people from another culture (we found most of them by referencing a previous meta-analysis by Elfenbein & Ambady, 2002). Using data involving 82 different nations, we found that the more heterogeneous the expresser’s culture, the better perceivers from other cultures were able to accurately categorize the emotion being expressed. These findings fit the idea that as heterogeneous cultures gradually develop, they cultivate easily recognizable nonverbal expressions as a means of communication and social bond formation.

Our approach to studying cultural influences on expression of emotion emphasizes dual forces that shape how we emote. Emotional expressions look the way they do partly because of genetic evolutionary pressures. But they are therefore also influenced by norms established by the different communicative needs of our environments, reflecting cultural evolution. The next time you hear someone say that one culture has fake smiles, or another culture is too stoic and reserved, remember that each culture’s expressive dialect is the result of fascinating historical influences. And that is something we can all smile about.

Colored World Map Showing Migration Patterns

Greener countries are more heterogeneous, meaning their present-day populations originate from a greater number of source countries (values on legend refer to number of source countries). Image generated at and based on data from World Migration Matrix.

Adrienne Wood is a PhD student in Psychology at the University of Wisconsin – Madison, where she researches the interaction between cognition and emotion with her advisor, Dr. Paula Niedenthal. Visit the Niedenthal Emotions Lab website ( or Adrienne’s website ( to learn more.  


Image generated at and based on data from World Migration Matrix.