ANCESTRAL DIVERSITY & EMOTION CULTURE

Human survival depends on our ability to coordinate our behavior with the people around us. This can already be a challenging task when we share a language, social scripts, traditions, and norms. Establishing trust and mutual understanding with other people becomes even more challenging when you don't share a culture and language. This is a situation people often find themselves in when they immigrate to a new land. Some present-day cultures, like the U.S. and Brazil, are built on hundreds of years of immigration from a variety of source countries.

We propose that settlers in historically heterogeneous lands established communication and trust by developing a culture of greater emotional transparency. People are perceived as more trustworthy and are easier to understand when they produce bigger, clearer nonverbal expressions, and greater expressivity could compensate for the lack of shared language, norms, and institutions in heterogeneous cultures. Once a culture of greater emotional transparency is established, it can persist over generations, even as the new culture converges on a common language and norms. We study the emotion consequences of historical heterogeneity, which can be quantified as the number of source countries that contributed to a present-day nation's population over the course of 500 years.

Below we describe evidence that the historical heterogeneity scores of countries (see map) explains between-cultural variability in present-day expressivity. See our recent Perspectives on Psychological Science piece for more details.

People from heterogeneous cultures are more emotionally expressive

We used heterogeneity scores to predict the self-reported emotional display rules of participants from 32 countries. We found that people from historically heterogeneous cultures thought it was more appropriate to express feelings openly, compared to people from homogeneous cultures. A massive behavioral study (N=866,726) from a separate lab supports our initial finding, showing that heterogeneity scores predict how much people smile while watching videos in front of a webcam. In our own work, we have found that ancestral diversity predicts the frequency of smiling both across countries and across the states of the United States (2018).

They produce more cross-culturally recognizable facial expressions 

In another paper (2016) we re-analyzed data on cross-cultural emotion recognition accuracy from 92 articles using participants from 82 separate cultures. We used the historical heterogeneity scores of both the expressers' cultures and the perceivers' cultures to predict accuracy and found that the more heterogeneous the expresser's culture, the greater the cross-cultural emotion recognition accuracy. This effect persisted even when we included in our model another important cultural dimension, individualism-collectivism. We suggest that heterogeneous cultures experienced increased pressure to use clear facial signals that are more universally recognizable, creating between-culture variability in expression recognizability.

And they emphasize different reasons for smiling

We study 3 specific tasks we consider fundamental to social living: rewarding the behavior of others, affiliating and maintaining bonds, and exerting dominance for the purposes of status negotiation. Smiles and laughter are particularly well-suited for solving all 3 tasks. While people across cultures confront these tasks, cultures vary in the extent to which the tasks are encountered in daily life. In high ancestrally diverse cultures where norms and and language were or are not initially shared, people feel greater pressure to reduce uncertainty and establish trust with others. We predicted that people in high ancestrally diverse cultures use smiles to signal friendliness and affiliation more than people in low ancestrally diverse cultures. We found support for this idea (2015) when we asked participants from 9 countries to rate the extent to which 15 different emotional/motivational states cause people to smile in their culture. Participants clustered into two groups based on their responses, with significantly more participants from ancestrally diverse cultures in the cluster that emphasized affiliation-related reasons more.

REPRESENTATIVE PUBLICATIONS

Niedenthal, P. M., Hampton, R. S., & Marji, M. (2023). Ancestral diversity: a socioecological account of emotion culture. Current Directions in Psychological Science, 32(2), 167-175.in press.

Niedenthal, P. M., Rychlowska, M., Zhao, F., & Wood, A. (2019). Historical migration patterns shape contemporary cultures of emotion. Perspectives on Psychological Science, 1745691619849591.

Niedenthal, P. M., Rychlowska, M., Wood, A., & Zhao, F. (2018). Heterogeneity of long-history migration predicts smiling, laughter and positive emotion across the globe and within the United States. PloS one, 13(8).

Wood, A., Rychlowska, M., & Niedenthal, P. (2016). Heterogeneity of long-history migration predicts emotion recognition accuracy. Emotion, 16, 413-420.

Rychlowska, M., Miyamoto, Y., Matsumoto, D., Hess, U., Gilboa-Schechtman, E., Kamble, S., … Niedenthal, P.M. (2015). Heterogeneity of long-history migration explains cultural differences in reports of emotional expressivity and the functions of smiles. Proceedings of the National Academy of Sciences of the United States of America, 112, E2429–E2436.