CONSTRUCTING NAIVE THEORIES OF MOTION ON THE FLY

People often make erroneous predictions about the trajectories of movi ng objects. McCloskey (1983a, 1983b) and others have suggested that ma ny of these errors stem from well-developed, but naive, theories of mo tion. The studied presented here examine the role of naive impetus the ory in people's judgments of motion. Subjects with and without formal physics experience were asked to draw or select from alternatives the trajectories of moving objects that were presented in various manners. Results from two experiments indicate that both trajectory judgments and explanations were affected by specific response and display featur es of the problem. In addition, these data provide little evidence tha t naive impetus theory plays a significant role in subjects' performan ce; instead, they suggest that motion judgments and explanations are c onstructed on the fly from contextual cues and knowledge that is not n ecessarily naive.