In 2 separate longitudinal studies, infants and their mothers were seen in 3 longitudinal visits. At 2 months, they were observed in free play where mothers' contingency toward their infants was obtained. At 5 months, a goal blockage response was produced when a previously learned contingent response became ineffective in producing an interesting event. Infants' emotional responses, in particular anger and sad facial expressions, were observed. At 2 years, toddlers' persistence at play was assessed by measuring children's responses to an interruption of their play. In both studies, the amount of toddlers' persistence was positively related to their anger response to the blocked goal at 5 months. Maternal contingency was not related either to infants' response to the blocked goal or to their persistence at play. These findings provide evidence for the contribution to and the consequences of infants' response to a goal blockage and the role of anger as an approach emotion.