The changes in preschool children's effective play, affective involvement, and social interaction across a 6-month period of nursery school attendance were examined. Videotaping of the children's activities was done in January/February (pretesting) and May/June (posttesting). The result was a total of approximately 40 hours of tape covering many aspects of the children's day in school. The taping strategy involved 15-minute random order time sampling of various settings within the school such as the block area, family life area, sand play area, and slide area. Each child in a particular setting was rated on the level of his play (examination, repetition, combination, transformation), the level of his affective involvement (distractible, engrossed), and his level of social interaction (solitary, associative, exchange). These individual ratings were then combined to generate overall scores for each setting which were analyzed for pre-post differences. The changes across time for each setting are discussed, interpretations are offered, and some suggestions for change are made. (JMB)