One of the key developmental tasks in adolescence is to develop a coherent identity. The current review addresses progress in the field of identity research between the years 2010 and 2020. Synthesizing research on the development of identity, we show that identity development during adolescence and early adulthood is characterized by both systematic maturation and substantial stability. This review discusses the role of life events and transitions for identity and the role of micro‐processes and narrative processes as a potential mechanisms of personal identity development change. It provides an overview of the linkages between identity development and developmental outcomes, specifically paying attention to within‐person processes. It additionally discusses how identity development takes place in the context of close relationships.

Identity formation is one of the key developmental tasks in adolescence. According to Erikson (1968) experiencing identity uncertainty is normative in adolescence. However, empirical studies investigating identity uncertainty on a daily basis are lacking. Hence, studying individual differences in daily certainty (i.e., identity commitment levels) and uncertainty (i.e., identity commitment fluctuations and identity reconsideration) in the identity formation process may advance our knowledge about the extent to which adolescents' identity uncertainty is part of normative identity development. Therefore, this longitudinal study examined heterogeneity in certainty and uncertainty dynamics of adolescents' daily identity formation using a longitudinal microlevel approach. Dutch adolescents (N = 494; Mage = 13.03 years at T1; 56.7% boys) reported on 2 key dimensions of identity formation (i.e., commitment and reconsideration) in both the educational and interpersonal domain on a daily basis for 3 weeks within 1 year, across 5 successive years. Multivariate latent class growth analyses suggested both in the educational and interpersonal identity domain a class of adolescents displaying a "crisis-like" identity formation process, and an "identity synthesis" class. Classes revealed differential development of (global and school) anxiety, aggression, and best friend support. Taken together, the present study confirmed Erikson's notion that experiencing daily identity uncertainty is common during adolescence. However, a substantial amount of adolescents also showed a process toward identity maturation already during adolescence. (PsycINFO Database Record

Adolescence is a formative period for socio-emotional development which is threatened by the COVID-19 pandemic. The current longitudinal study examined two aims: (1) the short- and long-term effects of the pandemic on young people’s mood (i.e. vigor, tension, and depression levels) and emotional reactivity (i.e. fluctuations in daily mood), and (2) the impact of stressors on mood, emotional reactivity, self-oriented (i.e. maladaptive behavior towards COVID-19 rules) and other-benefitting behaviors (i.e. behavior aimed at helping and comforting others). We conducted an online two-week daily diary study among 462 Dutch adolescents (Mage = 15.27 years, 64% females) and 371 young adults (Mage = 21.49 years, 81% females) in May 2020, with a follow-up in November 2020 (N = 238 and 231, respectively adolescents and young adults). In May 2020, young adults and older relative to younger adolescents showed higher levels and more fluctuations in tension and depression and lower levels of vigor. Vigor levels decreased and tension and depression levels increased between May 2020 and November 2020, especially for younger adolescents. There were positive associations between instability of negative emotions (i.e. tension and depression fluctuations) and the exposure to stressors (i.e. family stress and inequality of online homeschooling) in the adolescent sample. Together, this study demonstrates vulnerability regarding young people’s mood and emotional reactivity during the COVID-19 pandemic, especially for adolescents who experience more stressors.