Age running its course: Most people’s personality closely follows their age

Based on previous findings and psychometric reasoning, we hypothesized that personality traits closely follow chronological age (chronAge), but that this has been obscured by reliance on limited and single-method personality assessments. We investigated how accurately chronAge could be predicted from personality traits (persAge) in 13,253 individuals (aged 20 to 70) whose personality domains and nuances had been comprehensively assessed by themselves and a close informant. Observed persAge, based on self-ratings or combined self- and informant-ratings, correlated with chronAge up to r ≈ .80. Latent persAge, based on the shared variance of both assessment sources, correlated with chronAge up to r ≈ .90. Over the 50-year age span, we estimated typical differences between chronAge and latent persAge to be less than 4.5 years. This implies latent persAge differences so large that the persAge distributions of younger and older people barely overlap. These findings suggest a strong normative component in personality development as a whole. Yet, individuals can arrive at the same persAge differently, and normative age-related factors are only one reason why people differ on any given trait.