Historical heterogeneity

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. Our lab studies a particular cultural solution for communicating and establishing trust with people in historically diverse cultures.

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 expression 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 Current Opinion in Psychology piece for more details.

 Number of unique source countries that contributed to each present-day nation's population over 500 years of migration (numbers from  Putterman & Weil, 2010 ).

Number of unique source countries that contributed to each present-day nation's population over 500 years of migration (numbers from Putterman & Weil, 2010).

 
 Percent of explained cultural variability in emotion expressivity predicted by historical heterogeneity along with other cultural variables ( Rychlowska et al., 2015 )

Percent of explained cultural variability in emotion expressivity predicted by historical heterogeneity along with other cultural variables (Rychlowska et al., 2015)

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 more historically heterogeneous cultures thought it was more appropriate to express feelings openly, compared to people from more 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.


They produce more cross-culturally recognizable facial expressions 

In another paper 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.

smiling_people_from_south_america.jpg

 Two Korean  Hahoetal  masks displaying noticeably different smiles (left: the powerful, domineering aristocrat Yangban; right: the affiliative, flirtatious Pune).

Two Korean Hahoetal masks displaying noticeably different smiles (left: the powerful, domineering aristocrat Yangban; right: the affiliative, flirtatious Pune).

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 (see Social Functions section for details). According to our social functional account, smiles and laughter are particularly well-suited for solving all 3 tasks. While we propose that all people across cultures must solve these 3 tasks, different cultural contexts may make particular tasks more or less relevant to daily life. In homogeneous cultures, which historically experienced greater population stability, cultural norms and hierarchical relationships are typically clearer than in heterogeneous cultures. We therefore predicted that people in homogeneous cultures would consider status negotiation (dominance) to be a better reason for smiling than people in more heterogeneous cultures. Because people in heterogeneous cultures historically experienced increased pressure to reduce uncertainty and establish trust with others, we predicted people in heterogeneous cultures would endorse reasons for smiling related to friendliness and affiliation more than people in homogeneous cultures. We found support for these predictions 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 homogeneous cultures in the cluster that emphasized hierarchy-related reasons for smiling more and affiliation-related reasons less.