Closer to the Core: A Multi-Informant Longitudinal Perspective on Personality

Abstract

As a multifaceted construct, personality is like a mountain. It may take on different shapes when looking from different perspectives – far or near, high or low, outside or inside. Its view may be colored when looking through different lenses. The current personality literature is primarily built on the “insider’s views”, as it heavily relies on self-reports of personality. However, the (implicit) assumption in the literature that changes in self-reported personality reflect “true” trait changes disregards several critical limitations of the self-report method, such as blind spots and self-representation motives (e.g., Paulhus & Vazire, 2007; Vazire, 2010; Vazire & Carlson, 2011). This dissertation investigated the multifaceted nature of personality in a developmental framework. By complementing self-reports with personality judgments from multiple knowledgeable informants, this dissertation takes us one step closer to the core of personality and its development. This dissertation was guided by models derived from adult literature with predominantly cross-sectional design, such as the Self-Other Knowledge Asymmetry Model (the SOKA model; Vazire, 2010) and self-verification theory (Swann, 2011). It was investigated whether these models could generalize to personality development from late childhood to young adulthood. Specifically, Chapter 2 examined the temporal consistency of personality from late childhood to young adulthood as perceived from multiple perspectives. In two longitudinal studies, we consistently found mean-level change and rank-order stability of personality to depend on the judge in meaningful ways, suggesting that personality its development are at least partly socially constructed. These results confirmed and expanded the predictions from the SOKA model (Vazire, 2010) to describe youth personality development. Chapter 3 examined the utility of each perspective in predicting future personality and life outcomes (e.g., internalizing and externalizing problems, educational and occupational achievement, and relationship quality). Results supported the unique insights of close others regarding adolescent’s personality by showing that personality reported by parents and friends predicted future personality and various life outcomes over and above self-reported personality. Consistent with the SOKA model, this was especially true for the highly visible and evaluative traits (i.e., conscientiousness, agreeableness, and openness). Based on self-verification theory (Swann, 2011), which posits the beneficial effects of self-other personality agreement, Chapter 4 and 5 investigated the longitudinal implications of interjudge (dis-) agreement regarding adolescents’ personality on their adjustment. Chapter 4 examined the association between self-other agreement on personality profile and later self-esteem development, using longitudinal data spanning 18 years. Chapter 5 examined the associations between self-other agreement on personality traits and later internalizing problems using Response Surface Analysis. Results suggested that the implication of self-other personality agreement may depend on the type of agreement, the target-judge dyads, and targets’ gender and developmental stage (i.e., early vs. late adolescence). This dissertation used comprehensive longitudinal datasets and the state-of-the-art statistical techniques to shed light on some basic and important questions regarding the structure and development of youth personality. Multi-informant studies are crucial for a more accurate understanding of the temporal consistency of personality and the influences of personality traits, social perceptions, and social consensus on individuals’ success across the lifespan.