Explaining human movements and actions: children's understanding of the limits of psychological explanation.

Human actions and movements can be caused by psychological states (e.g. beliefs and desires), physical forces (e.g. gravity) and biological processes (e.g. reflexes). In three studies we explored young children's understanding of the causes of human movements in order to examine their ability to differentiate and coordinate psychological, physical and biological reasoning to account for the activities of one single entity--a human being. In Study 1, 4-year-olds explained characters' voluntary actions, mistakes, physically-caused and biologically-caused behaviors and movements. Children gave psychological explanations for the intended actions and mistakes, but biological and physical explanations for the biologically-caused and physically-caused movements. Studies 2 and 3 extended the investigation to younger children (3-year-olds), encompassed a greater variety of items, and used several converging methods in order to examine children's judgments and explanations. Consistently, 3- and 4-year-olds gave appropriately different responses and explanations to the different item types. These findings show that far from viewing people in strictly psychological terms, young children evidence multiple causal-explanatory construals of human behavior. We discuss the implications of these findings for children's everyday psychological, physical, and biological theories. One implication of the findings is that young children do not assume a match between entities and theories (persons-psychology, objects-physics). If they do not, this raises the question of what information they use to decide which explanatory system fits which events.