The report presents a description of an instrumental conditioning apparatus designed to serve as a personality assessment procedure. In this procedure, a visual stimulus was made contingent upon a lever-pressing response. The magnitude of the change in rate in responding constituted the dependent measure. The stimuli consisted of cartoons portraying social behaviors that had in the past for the children studied been associated as conditioned stimulii for pain. Each of the Ss was observed over a 5 week period in a nursery school setting. The number of occasions on which each child was victimized by an aggressor was recorded. It ws predicted that children who had been more frequently victimized would show a greater impairment in the rate of responding when such stimuli were made contingent upon lever pressing. The prediction was confirmed.