Co‐Development of Adolescents' Cooperative and Competitive Attitudes: How it Predicts Mental Health and Academic Achievement

This study used nationally representative longitudinal data in South Korea to examine how joint changes in adolescents' (N = 7324; M (age) ≈ 11 years) cooperative and competitive attitudes from sixth to ninth grade relate to mental health and achievement in 10th grade. The parallel process model showed that both cooperative and competitive attitudes declined over time. Higher cooperative attitudes at baseline indicated higher competitive attitudes, and a faster decline in cooperative attitudes indicated a faster decline in competitive attitudes. The intercept of cooperative attitudes was positively related to mental health but negatively related to achievement. Opposite patterns were found for the intercept of competitive attitudes. These findings highlight the usefulness of considering the co‐development of cooperative and competitive attitudes.