Current Trends, Future Perspective, and Challenges in Personality Research:

Abstract

This study aims to review longitudinal research on personality traits and identity process, and suggests further developments in personality research. To accomplish these aims, the author first confirms the conceptual validity among self, identity, and personality traits based on the three standard identity theory proposed by McAdams & Zapata-Gietl ( 2014 ). Second, the author reviews longitudinal research on personality traits, and discusses how personality trait changes are explained by the social investment principle and changes in self-concept clarity, volition, and sense of adjustments. Third, the author reviews identity process research and discusses the longitudinal relationships between identity processes and psychosocial problems and the specific characteristics of identity processes in Japan. Fourth, the author reviews longitudinal research in mutual development between personality traits and identity processes and discusses how directions of association between personality traits and identity processes are different depending on developmental stages. Fifth, the author proposes the " personal investment principle " which explains the development of personality traits in adolescence. Finally, the author discusses future perspectives and challenges in personality research.