LAUSR

Human emotional behavior varies across cultures. Smiling at a passing stranger on the street may seem perfectly normal in one culture and profoundly strange or even suspicious in another. What are the origins of cultural differences in emotional expression, communication, and regulation? We review new evidence in favor of one answer to this question. A socioecological factor, historical heterogeneity—defined as the ancestral diversity of the world’s regions based on human migration patterns over centuries—accounts for important cultural variations in emotional experience and expression. We summarize findings from studies of large global samples that link the migratory history of a country’s population with present-day cultural differences in how overtly and clearly emotions are expressed to others, in the frequency and meaning of smiles, and in associated character traits. New research also extends the analysis to the historical heterogeneity of the United States, and country-level findings are replicated at the level of the states. We suggest that enduring emotional behaviors and traits evolve from the opportunities and challenges posed by the commingling of people of diverse ancestries. We conclude by highlighting the questions and challenges for future research stemming from this approach.