This paper reports the results of two related studies. The primary purpose of the first study (involving both nursery and first grade subjects) was to determine what evidence there is of two distinct processes basic to the control over the initiation and inhibition of inappropriate behavior on the Luria task. In the second study the focus of interest was in the relationship between impulsive behavior and the child's success with the academic work presented in the first grade. Other than the fact that the interstimulus interval in the Luria task was shortened to increase the difficulty level to one more appropriate for the first graders, the inclusion of indices of school learning constituted the only departure from the procedure used in the first study. Hence the results of study two permit an important check on the reliability of the initial findings. The data were consistent in indicating that distinct impulse control problems on the Luria task persist longer in the development of the lower SES child than the child of middle SES. The evidence consistently indicated that impulsive behavior is a more general phenomenon in the lower SES than in the middle SES. There is also reason to believe that this general control problem, in the lower SES, was related to the sorts of impulsive behavior observed by their teachers in the classroom. When intelligence was controlled, lower SES subjects obtained significantly poorer relationship between Luria task impulsively and grades in the middle SES. (Author/JM)