Zins, Weissberg, Wang, and Walberg (2004) note that research proves conclusively that students’ social-emotional competence developed through social and emotional learning programs and conflict resolution education fosters better academic performance. When students are more self-aware and emotionally connected they can focus on academics and achieve in a supportive environment.

The kinds of supports that produced these impacts included:
(a) safe and orderly school and classroom environments,
(b) caring relationships between teachers and students that foster commitment and connection to school,
(c) engaging teaching approaches such as cooperative learning and proactive classroom management.

Zins, J. E., Weissberg, R. P., Wang, M. C., & Walberg, H. J. (Eds.). (2004). Building academic success on social and emotional learning: What does the research say? New York: Teachers College Press.

In a quantitative review of 213 school-based Social Emotional Learning (SEL) studies, SEL programs significantly decreased the number of suspensions and expulsions while improving school attendance, students’ attitudes towards school, students’ grades, and performance on achievement tests. The most impressive finding was students’ improvement on standardized test scores, which increased by the equivalent of 11 percentile points. See Durlak, J. A., Weissberg, R. P., Dymnicki, A. B., Taylor, R. D. and Schellinger, K. B. (2011), The Impact of Enhancing Students’ Social and Emotional Learning: A Meta-Analysis of School-Based Universal Interventions. Child Development, 82: 405–432

This SEL performance research brief from CASEL is a good place to start with respect to understanding how constructive classroom environments may impact positively on academic achievement.