Growing suspension rates predict major negative life outcomes, including adult incarceration and unemployment. Experiment 1 tested whether teachers (n = 39) could be encouraged to adopt an empathic rather than punitive mindset about discipline-to value students' perspectives and sustain positive relationships while encouraging better behavior. Experiment 2 tested whether an empathic response to misbehavior would sustain students' (n = 302) respect for teachers and motivation to behave well in class. These hypotheses were confirmed. Finally, a randomized field experiment tested a brief, online intervention to encourage teachers to adopt an empathic mindset about discipline. Evaluated at five middle schools in three districts (Nteachers = 31; Nstudents = 1,682), this intervention halved year-long student suspension rates from 9.6% to 4.8%. It also bolstered respect the most at-risk students, previously suspended students, perceived from teachers. Teachers' mindsets about discipline directly affect the quality of teacher-student relationships and student suspensions and, moreover, can be changed through scalable intervention.

A global priority for the behavioural sciences is to develop cost-effective, scalable interventions that could improve the academic outcomes of adolescents at a population level, but no such interventions have so far been evaluated in a population-generalizable sample. Here we show that a short (less than one hour), online growth mindset intervention-which teaches that intellectual abilities can be developed-improved grades among lower-achieving students and increased overall enrolment to advanced mathematics courses in a nationally representative sample of students in secondary education in the United States. Notably, the study identified school contexts that sustained the effects of the growth mindset intervention: the intervention changed grades when peer norms aligned with the messages of the intervention. Confidence in the conclusions of this study comes from independent data collection and processing, pre-registration of analyses, and corroboration of results by a blinded Bayesian analysis.