Abilities of 2-, 5-, and 7-year-old children to interpret, judge acceptability of, and produce class extensions were assessed. It was concluded that increasing ability to deal appropriately with class extensions is primarily due to general advances in language acquisition rather than to any development unique to the class-extension word-formation…

Provides a general analysis of the problem of relating private, cognitive mechanisms of individuals to their public behavior. A computational model of language acquisition is offered. Conclusions are related to Piaget's notion of mutual verification and to some general philosophical questions about learning. (Author/RH)

Adults' perceptions of infants' cries were evaluated by means of multidimensional scaling. Twenty-four nonparents and 20 parents judged the similarity of all possible pairs of 12 recorded cries. Subjects also rated the cries on 29 attributes, including perceived aversiveness, possible caretaking responses, affective responses, and semantic…

Compares two types of semantic development (the acquisition of disappearance words and success-failure words) to performance on two types of cognitive tasks (object-permanence and means-ends tasks) among infants. (HOD)