Abstract
OBJECTIVE: Substantial literature indicates that personality traits are integral to well-being and health in aging. We examined time trends in personality over birth cohorts spanning 45 years. METHODS: We used two community-based studies of 3,000 older adults at Rush Alzheimer's Disease Center, continuously enrolled since the 1990s and born across seven birth cohorts: 1905-1914, 1915-1919, 1920-1924, 1925-1929, 1930-1934, 1935-1939, and 1940-1950. Conscientiousness, neuroticism, and extraversion were assessed using components of the NEO five-factor personality inventory. RESULTS: Overall, the mean age was 79 years (interquartile range: 73-84). Within birth cohorts, mean age ranged from 87 years (standard deviation [SD] ± 4.8) among those born in 1905-1914 to 72 ± 4.3 years among those born in 1940-1950. Over 90% of participants were white, and about one-quarter were male. Given the modest age range, age was not related to personality, although sex and study varied; we compared sex- and study-standardized mean levels of personality across birth cohorts. We found strong associations of later birth cohort with lower neuroticism (e.g., mean ± SD neuroticism was 16.7 ± 6.3 for the 1905-1914 birth cohort; 15.8 ± 6.5 in 1925-1929; 15.2 ± 7.0 in 1940-1950; overall p < .0001 across birth cohorts). Similarly, conscientiousness was higher with later birth cohort (e.g., mean ± SD conscientiousness was 33.7 ± 4.7 in the 1905-1914 birth cohort; 33.9 ± 5.6 in 1925-1929; 35.3 ± 5.9 in 1940-1950; overall p < .0001). Trends were weak for extraversion. DISCUSSION: We found associations of later birth cohort with lower neuroticism and higher conscientiousness among older adults. Findings suggest that personality at older ages is amenable to population-level shifts, with implications for health.