Paper #1: Changes in Academic Motivation: Six-cohort Japanese samples by longitudinal study over 2-year period. Takuma Nishimura (University of Tokyo, University of Rochester), with Shigeo Sakurai Paper #2: Cross-lagged model of the development of competence, relatedness and autonomy in adolescence considering social relations and self-concept at school Olga Bakadorova (Ernst-Moritz-Arndt-Universitt Greifswald), with Diana Raufelder Paper #3: Emotional and motivational costs and benefits of positive and negative perfectionism in high school students over a period of six months Isabelle Green-Demers (University of Quebec in Outaouais), with Daniel Pelletier