Preventing Violence in the Most Violent Contexts: Behavioral and Neurophysiological Evidence from El Salvador.

This article evaluates the impacts of an after-school program (ASP) implemented in five public schools in El Salvador, a country with extremely high levels of youth violence, aiming to reduce school violence and improve academic outcomes among vulnerable 10–16-year-old students. The ASP combined cognitive behavioral therapy (CBT)-inspired social skills development with extracurricular activities and was delivered over 20 weeks to randomly assigned participants. Results from the randomized experiment indicate that the program significantly reduced violent and delinquent behaviors, improved attitudes toward school and learning, increased homework time and class attention, reduced absenteeism, and modestly raised the probability of passing courses. The study also provides novel, exploratory evidence using electroencephalogram (EEG) biomarkers suggesting that the intervention enhanced participants' emotion regulation, potentially explaining behavioral improvements. Additionally, analyses accounting for spillover effects show that treated and untreated students in classrooms with higher treatment saturation both benefited, implying that improved classroom environments contributed to the program's overall effectiveness.