Two studies exposed children and adults to an illusion created by perceptual adaptation, in which subjects perceived two identical bottles, held simultaneously in a different hand, as being different in weight. Feedback and repeated trials led older children and adults to improve performance in determining correct weights. The role of feedback,…

Discusses variables related to task performance in the solution of the water-level problem, where subjects were asked to indicate the water surface orientation in a tilted vessel. Subjects ages 7 to 15 years participated. Suggests that field effects and the kind of rules in use contribute to the differences in performance, which can be shown even…