The role of verbalization in children's mental operations was studied by comparing the mental operations children used in spatial perspective tasks (indicating another's view) and rotation tasks (imagining an object's rotation and one's own subsequent view). Each of 96 children (equal numbers of boys and girls, kindergarten and second grade students) was given one of the tasks and asked to respond either verbally or by picture selection. The results indicated that verbalizations led to substantially more correct responses on the perspective task, but not on the rotation task. Errors on the perspective task appeared primarily due to a failure to use the rule that a person in a different vantage point sees a different view, whereas errors on the rotation task appeared primarily due to failures in the computation process of determining exactly the nature of the new view. It was proposed that children manipulate descriptions of object features in perspective taking, while they manipulate more holistic images in rotation tasks. (Author/RL)