The Longitudinal (Co)Development of Personality Traits and the Level of Personality Functioning After Negative Life Events

Based on the evidence from cross-sectional studies, there is an ongoing debate whether personality traits and personality functioning are redundant (e.g., because these constructs are strongly correlated). However, some questions regarding their overlap can only be addressed using longitudinal data. In this Registered Report, we examined the (co)development of the Big Five personality traits and personality functioning using longitudinal data from individuals who had recently experienced a negative life event (N = 1,151). Personality functioning was less rank-order stable than conscientiousness and less mean-level stable than all Big Five traits except neuroticism. Furthermore, the developmental trajectory of the level of personality functioning was particularly similar to the developmental trajectory of neuroticism. Our results show that personality functioning and most Big Five personality traits differ in their longitudinal development in the context of negative life events and suggest the need for a clearer distinction between personality functioning and neuroticism.