A new study from Northwestern University revealed that in order to fully reap the cognitive benefits of a music class, kids can’t just sit there and let the sound of music wash over them. They have to be actively engaged in the music and participate in the class. “Even in a group of highly motivated students, small variations in music engagement — attendance and class participation — predicted the strength of neural processing after music training,” said Nina Kraus, director of Northwestern’s Auditory Neuroscience Laboratory, in an email to TIME. She co-authored the study with Jane Hornickel, Dana L. Strait, Jessica Slater and Elaine Thompson of Northwestern University.