DESCRIPTION (Adapted from applicant's description): The specific goal of the proposal is to examine how variations in frustrating events are linked to differences in infants' negative emotions and instrumental behavior. The study will systematically vary two aspects of expectancy, examining the separate and combined impact of their violation on infants emotional and instrumental behavior. The study uses a contingency learning/frustration procedure to study infants facial expression and instrumental responses. Twenty-week-old infants will be trained to expect that their pulling on a string results in a pleasant event. A brief frustration period, followed by reinstatement of the contingency, allows observation of infant responses when two specific aspects of that contingency are violated. During the frustration period, one or both aspects will be violated, following a model of contingency perception developed by Watson and others. Infants will be randomly assigned to groups which will experience either reduced predictability, reduced controllability, or their combination during frustration. Group differences observed during frustration will show whether violating expectancies about the predictability of the stimulus, its controllability, or both affects infants instrumental behavior and negative emotions.