An individual's emotions system can be conceived of as a synchronized, coordinated, and/or emergent combination of physiology, experience, and behavioral components. Together, the interplay among these components produce emotional experiences through coordinated excitatory positive feedback (i.e., the mutual amplification of emotion concordance)…

Lifespan research has long been interested in how contexts shape individual development. Using the separation and later reunification of Germany as a kind of natural experiment we examine whether and how living and dying in the former East or West German context has differentially shaped late-life development of well-being. We apply multi-level…

A large body of research has documented changes in self-esteem across adulthood and individual-difference correlates thereof. However, little is known about whether people maintain their self-esteem until the end of life and what role key risk factors in the health, cognitive, self-regulatory, and social domains play. To examine these questions,…

Well-being is often relatively stable across adulthood and old age, but typically exhibits pronounced deteriorations and vast individual differences in the terminal phase of life. However, the factors contributing to these differences are not well understood. Using up to 25-year annual longitudinal data obtained from 4,404 now-deceased…

Late-life well-being often shows steep deteriorations, but the contributing factors are not well understood, in part because data about people's final year of life are scarce. Here, we draw from and test theoretical perspectives that health-related vulnerabilities undermine the experience and skills older adults typically use to maintain…

Growth mixture modeling (GMM) is a method for identifying multiple unobserved sub-populations, describing longitudinal change within each unobserved sub-population, and examining differences in change among unobserved sub-populations. We provide a practical primer that may be useful for researchers beginning to incorporate GMM analysis into their…

Pubertal development is a nonlinear process progressing from prepubescent beginnings through biological, physical, and psychological changes to full sexual maturity. To tether theoretical concepts of puberty with sophisticated longitudinal, analytical models capable of articulating pubertal development more accurately, we used nonlinear…

Growth curve modeling has become a mainstay in the study of development. In this article we review some of the flexibility provided by this technique for describing and testing hypotheses about: (1) intraindividual change across multiple occasions of measurement, and (2) interindividual differences in intraindividual change. Through empirical…

Ideally, the unit of analysis in psychology is the individual. However, many psychological methods do not cope well, either at the level of construct definition or at the level of measurement, with individuality in behavior. There is little leeway for constructs to be both idiosyncratically tailored to the individual, and still identified as…

Weekly cycles in emotion were examined by combining item response modeling and spectral analysis approaches in an analysis of 179 college students' reports of daily emotions experienced over 7 weeks. We addressed the measurement of emotion using an item response model. Spectral analysis and multilevel sinusoidal models were used to identify…