Relationships among adult and young children's behavior in extended play encounters were examined. One group of normal six-year-old children completed 20 play encounters, while a second group of clinic-referred children completed 15 play encounters. Each child encountered either a trained/supervised or an untrained/unsupervised college undergraduate. Analyses of videotapes made of the "non-directive" play encounters indicated that the children who encountered trained/supervised undergraduates emitted greater numbers of fantasy behaviors, especially those indicative of mature, coping and adaptive functioning than did children encountering untrained/unsupervised undergraduates. Adult involvement in play and allowing the child self-direction seemed key behaviors in eliciting such child behavior. (Author/JLL)