In the Jyväskylä Longitudinal Study of Personality and Social Development (JYLS) the development of the same individuals (born in 1959) has been followed from age 8 to 50. The follow-ups have been conducted at 6–8-year intervals. The next data collection is planned to occur when the participants reach age 60.

The latest data collection took place in 2009 when the participants were 50 years old. Data were collected using a psychological interview and self-report inventories. Additionally, a medical examination was conducted. Information was gathered, among others, about well-being, personality, work and education, family, leisure time activities, social network, and health and health behaviors. Corresponding information has been collected earlier in adulthood, that is, at ages 27, 36, and 42. In childhood (at age 8) and adolescence (at age 14) the socioemotional behavior of the participants was assessed by teachers and peers. Data about the childhood upbringing environment is also available.

The JYLS data have been used in hundreds of national and international scientific publications, including both journals and books. Fifteen doctoral dissertations and dozens of master’s theses are based on the JYLS. The research themes have been related, for example, to the following: 1) socioemotional behavior and personality from childhood to adulthood, 2) the formation of education and working career, 3) family of origin and one’s own family, 4) health and health behaviors, 5) social adjustment and delinquency, 6) the development of well-being, and 7) mid-life development.

The ongoing JYLS study was initiated at the University of Jyväskylä by Lea Pulkkinen in 1968 who led the study until the end of 2012. Since the beginning of 2013, the JYLS has been led by Research Director Katja Kokko.

Further information about the study

Funding
The main funder of the JYLS has been the Academy of Finland (1974, 1979, 1986-2013). The latest data collection in 2009 was funded through the Academy of Finland research grants awarded to Lea Pulkkinen (no 127125) and Katja Kokko (no 118316).

Research group

Principal investigator
Research Director Katja Kokko, katja.r.kokko[at]jyu.fi, Gerontology Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä

Professor emerita Lea Pulkkinen, lea.pulkkinen[at]psyka.jyu.fi, Department of Psychology, University of Jyväskylä
Postdoctoral researcher Johanna Rantanen, k.johanna.rantanen[at]jyu.fi, Department of Psychology, University of Jyväskylä
Doctoral student Noora Jalonen, noora.h.jalonen [at]jyu.fi, Department of Psychology, University of Jyväskylä
Doctoral student Merja Hietalahti, merja.a.hietalahti[at]jyu.fi, Department of Psychology, University of Jyväskylä
Doctoral student, statistician, Anna-Liisa Lyyra, anna-liisa.lyyra[at]jyu.fi, Department of Psychology, University of Jyväskylä

There are several other researchers at the Departments of Psychology, Teacher Education, and Statistics, Agora Center, Gerontology Research Center, and School of Business and Economics of the University of Jyväskylä who currently utilize the JYLS data in their studies. The JYSLS researchers also collaborate with other national institutions, such as Central Finland Health Care District, University of Tampere, and Järvenpää Addition Hospital.

The JYLS is a member of two extensive international research networks: Center for the Analysis of Pathways from Childhood to Adulthood (CAPCA; http://rcgd.isr.umich.edu/capca/) and Irvine Network on Interventions in Development (INID; http://inid.gse.uci.edu/). The JYLS data are stored at the Finnish Social Science Data Archive, based at the University of Tampere, Finland (FSD; http://www.fsd.uta.fi/fi/).

Collaborators
Center for the Analysis of Pathways from Childhood to Adulthood (CAPCA)
Irvine Network on Interventions in Development (INID)
Finnish Social Science Data Archive (FSD)

Selected publications

Kokko, K., Korkalainen, A., Lyyra, A.-L., & Feldt, T. (2013). Structure and continuity of well-being in mid-adulthood: A longitudinal study.Journal of Happiness Studies, 14, 99–114.

Kokko, K., Pulkkinen, L., Huesmann, L. R., Dubow, E. F., & Boxer, P. (2009). Intensity of aggression in childhood as a predictor of different forms of adult aggression: A two-country (Finland and United States) analysis. Journal of Research on Adolescence, 19, 9–34.

Pulkkinen, L. (2006). The Jyväskylä Longitudinal Study of Personality and Social Development (JYLS). In L. Pulkkinen, J. Kaprio, & R. J. Rose (Eds.), Socioemotional development and health from adolescence to adulthood (pp. 29-55). New York, NY: Cambridge University Press.

Pulkkinen, L., & Kokko, K. (2012). Foundational issues in longitudinal data collection. In B. Laursen, T. D. Little, & N. A. Card (Eds.), Handbook of developmental research methods (pp. 129–147). New York, NY: The Guilford Press.

Pulkkinen, L., Kokko, K., & Rantanen, J. (2012). Paths from socioemotional behavior in middle childhood to personality in middle adulthood. Developmental Psychology, 48, 1283­–1291.