During the sameperiod ot time that children are making progress in the management of conflicts, they are also gaining in the level of sophistication of their positive interactions with each other. There is an increase, during the preschool years, in tile aver age number of different children played with, in the intensity of individual friendships. and in the propor tion of play time spent in friendly vs. unfriendly in teraction. The play episodes of the older preschool ers include more instances of working together to ward a common goal, sharing materials, and assum ing cooperative role relations in fantasy play (Barnes, 1971). Furthermore, children who are the most competent in these behaviors arewatched and imitated more than others and thus appear to pro vide role models for the less competent children (Vaughn and Waters, in press).