The papers included here are based on a 1971 symposium held at the annual meeting of the Western Psychological Association in San Francisco. The first three papers report the results of research carried out over the last few years at the Wisconsin Research and Development Center for Cognitive Learning. Levin's paper focuses on the effectiveness of verbal and imaginal cognitive strategies, and their development with age. Wolff's paper summarizes research in which the developmental course of imagery production is tied to the early sensorimotor activity of the young child. Davidson examines the relationship between imagery and language processes in the child, and the broader question of whether imagery is inextricably linked to meaning. Rohwer's paper deals with the difficult-to-determine task and population validities for supposedly easy-to-determine phenomena. (Author)