Consistency and change in idiographic personality: A longitudinal ESM network study.

The study of personality development primarily focuses on between-person, nomothetic assessments of personality using assessments of personality traits. An alternative approach uses individual, idiographic personality assessment, defining personality in reference to one's self rather than to others. Nomothetic approaches to personality development identify high levels of consistency in personality, even over decades. But the developmental pattern of idiographic personality is unclear, partially due to difficulties in assessing personality idiographically. We examine a number of traditional and novel idiographic modeling techniques using 2 years of ESM data from the Personality and Interpersonal Roles Study (PAIRS; N = 372 participants, total assessments N = 17,715). We computed idiographic lagged (lag 1 autoregressive) and contemporaneous (concurrent) graphical VAR models, as well as several other idiographic models, for each subject at the individual level at both waves, which are represented as networks. The utility and interpretation of these newer idiographic personality models at an individual level is demonstrated by using two example subjects. Across all participants, idiographic personality models were heterogeneous in structure, indicating the value of an idiographic approach. Contemporaneous, but not lagged, idiographic models were consistent over time. Despite normative levels of consistency, both types of idiographic models exhibited a great range of individual differences in consistency where some people were completely stable across two years whereas others were very unlike their former selves. In sum, we demonstrate that novel idiographic modeling techniques provide a useful tool to address questions of personality dynamics that were not possible with more traditional idiographic assessments. (PsycInfo Database Record (c) 2020 APA, all rights reserved).