The Project on Human Development in Chicago Neighborhoods (PHDCN) was a large-scale, interdisciplinary study of how families, schools, and neighborhoods affect child and adolescent development. One component of the PHDCN was the Longitudinal Cohort Study, which was a series of coordinated longitudinal studies that followed over 6,000 randomly selected children, adolescents, and young adults, and their primary caregivers over time to examine the changing circumstances of their lives, as well as the personal characteristics, that might lead them toward or away from a variety of antisocial behaviors. Numerous measures were administered to respondents to gauge various aspects of human development, including individual differences, as well as family, peer, and school influences. One such measure was the Circles instrument. It was administered to subjects in Cohorts 0 and 3 and obtained a measurement of the subject's motor control. Subjects were given a drawing of a circle and then asked to draw a circle, themselves, staying between lines on a sheet of paper given to them. Three different trials were administered. The initial trial served as a baseline. For the second trial, the subject was asked to draw the circle as quickly as possible, and for the third trial the subject was asked to draw the circle as slowly as possible.