Trends over 45 years in personality traits among older populations

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.

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.

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.

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.