Explaining the increase in individualism in the U.S. over the past 150 years.

Grossman and Varnum quantify shifts in eight cultural-level correlates of individualism reflected in the domains of cultural products (individualist and collectivist themes in books, behavioral patterns of uniqueness such as baby-naming practices, behavioral and demographic correlates of individualism-collectivism reflecting the strength of family ties such as family size, percentage of single-person households and multigenerational households, divorce rates, etc.) and test the relationship between these indicators and trends in pathogen prevalence, the number of disasters, urbanization, secularism, and socioeconomic structure. Their data suggest socioeconomic structure shifts have been the most potent predictor of changes across a wide range of individualism-related markers. Compared with blue-collar occupations, white-collar occupations afford and demand more autonomy and self-direction, and greater affluence enables individuals to pursue their own interests without consulting or depending on larger collectives. Their abstract:

Why do cultures change? The present work examined cultural change in eight cultural-level markers, or correlates, of individualism in the United States, all of which increased over the course of the 20th century: frequency of individualist themes in books, preference for uniqueness in baby naming, frequency of single-child relative to multichild families, frequency of single-generation relative to multigeneration households, percentage of adults and percentage of older adults living alone, small family size, and divorce rates (relative to marriage rates). We tested five key hypotheses regarding cultural change in individualism-collectivism. As predicted by previous theories, changes in socioeconomic structure, pathogen prevalence, and secularism accompanied changes in individualism averaged across all measures. The relationship with changes in individualism was less robust for urbanization. Contrary to previous theories, changes in individualism were positively (as opposed to negatively) related to the frequency of disasters. Time-lagged analyses suggested that only socioeconomic structure had a robust effect on individualism; changes in socioeconomic structure preceded changes in individualism. Implications for anthropology, psychology, and sociology are discussed.