Understanding Development from Adolescence Through Midlife—Extending the Study on Educational Courses and Psychosocial Development in Adolescence and Adulthood (BIJU)

• Applicants: Professor Dr. Michael Becker; Professorin Dr. Naemi Dorothee Brandt; Professor Dr. Simon Grund; Professorin Dr. Jenny Wagner
• Subject Area: Personality Psychology, Clinical and Medical Psychology, Methodology
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 576871090

What keeps us healthy and happy in life? How do the sources, conditions, and choices in adolescence mold where we stand later in life? With this project, we aim to address two key research gaps in the current literature on socio-emotional development: First, to what degree do early-life sources in the vibrant phase of adolescence have sustained effects on developmental trajectories across emerging adulthood and through midlife for general populations and minority groups? Second, what is the role of daily experiences and related short-term processes in predicting the development of socio-emotional characteristics across adulthood? Guided by principles of the life span approach, we address these aims based on three foci: First, we focus on interindividual differences in personality development to disentangle the role of early-life sources and conditions. Second, we focus on vulnerable populations to provide the basis for a nuanced investigation of whether developmental trends and processes generalize across sexual or migrant minorities. Finally, through a methodological focus on missing data and longitudinal data sets with many variables, we will be able to identify novel solutions for the statistical challenges faced by studies on lifespan development. To address these research aims, there is an urgent need for more detailed midlife data that is fueled by comprehensive, longitudinal data following individuals across multiple developmental periods, linking to conditions in early adolescence, allowing for integrated analysis of short-term and long-term effects, and giving insights into the challenges faced by sexual and migrant minorities. The current project is therefore applying for financial resources to continue the unique BIJU project. BIJU is the most comprehensive and second longest European study and has so far followed more than 4,000 individuals from early adolescence onwards for 30 years. Besides its unique time span, BIJU is singular in covering information on the personal and environmental level using both subjective (i.e., social relationship experiences, mental health) and objective (i.e., cognitive abilities, parental socio-economic resources) indicators. Only with the extension of BIJU can we investigate early-life sources in the critical period of adolescence and young adulthood to test their role for robust long-term socio-emotional development into midlife while considering changes in sources along the way. Additionally, the project will be able to contribute substantially to our understanding of developmental trends beyond majorities by examining two minority groups, focus on the specific everyday challenges of midlife to elucidate processes driving long-term personality change, and address the methodological complexities of our comprehensive lifespan study by developing innovative solutions and supporting other researchers facing similar challenges.

• DFG Programme: Research Grants