ABSTRACT
Take a stick or bar and place it horizontally on top of a box so that the greater part of the stick rests on the box and one end protrudes into space. Give this free end a sharp tap, and the stick does a somersault. Young children cannot picture this somersault, as we discovered in an earlier study con cerning imagined representation in which their difficulties were analyzed. Since this situation (or any similar one, with an object that is only partly supported) might be familiar to the subject, it seemed appropriate in a study on practical in telligence and cognizance of actions to construct an elemen tary type of catapult in order to see what the subjects do with it and how they conceptualize their actions.
