DESCRIPTION: Recent research suggests that by 2 years of age children already possess sophisticated intuitions about persons; for example, they understand overt human actions in terms of underlying mental states such as desires, perceptions, and emotions. The present research seeks to establish what are the precursors of these early understandings in infancy. Fourteen experiments will be conducted with infants aged 6 to 14 months using two distinct paradigms: a preferential-looking and a social-referencing paradigm. The experiments will examine several interrelated issues, including: Are infants able to use actors' perceptions and emotions to predict their subsequent actions? Are infants able to interpret an actor's action toward an object in terms of both (a) the actor's desire to obtain the object and (b) physical constraints imposed by the environment? And, finally, do infants realize that an actor's perception of and emotion toward an object are directed to that object (as opposed to, say, whatever object infants happen to be attending to at the time)?