The ontogenesis of agent: cognitive notion.

Children's early 1- and 2-word utterances appear to encode the concept of agent, thus suggesting that this semantic notion has its origin in prior sensorimotor development. Specifically, the nonverbal concept of agent has been alluded to in research regarding young children's development of the cognitive notion of causality and the pragmatic category of requests for action. In this study children's awareness of the nonverbal agent concept was defined by gestural behaviors--that is, actions on objects and other people--occurring during request interactions with their mothers and the investigator. Three children were observed in their homes approximately once a month for 1 year, from their 11th through 22nd months of life. During each hour-long visit, the children were engaged in free play and in tasks designed to result in the children's requesting help from an adult. Based on the observation of the children's changing nonverbal behaviors over the 12 months, a 5-level developmental sequence documenting the evolution of the cognitive notion of agent is presented.