Cross-cultural temperamental differences in infants, children, and adults in the United States of America and Finland.

Cross-cultural differences in temperament were investigated between infants (n = 131, 84 Finns), children (n = 653, 427 Finns), and adults (n = 759, 538 Finns) from the United States of America and Finland. Participants from both cultures completed the Infant Behavior Questionnaire, Childhood Behavior Questionnaire and the Adult Temperament Questionnaire. Across all ages, Americans received higher ratings on temperamental fearfulness than Finnish individuals, and also demonstrated higher levels of other negative affects at several time points. During infancy and adulthood, Finns tended to score higher on positive affect and elements of temperamental effortful control. Gender differences consistent with prior studies emerged cross-culturally, and were found to be more pronounced in the US during childhood and in Finland during adulthood.