Inclusion Criteria:  enrolling in Kindergarten has a date of birth 4 months prior to the respective state cut-off for school entry does not have an Individualized Education program for behavioral concerns has not been retained in school or "red-shirted" by parents.  Exclusion Criteria:  outside of the targeted birthdate range diagnosed with autism, psychosis, or disruptive mood dysregulation disorder taking psychoactive medication for mood, behavior, or inattention, in a classroom with an already enrolled study participant.