Children sometimes make "scale errors," attempting to interact with tiny object replicas as though they were full size. Here, we demonstrate that instrumental tools provide special insight into the origins of scale errors and, moreover, into the broader nature of children's purpose-guided reasoning and behavior with objects. In Study 1, 1.5- to…

Understanding how responses become prepotent is essential for understanding when inhibitory control is needed in everyday behaviour. We investigated prepotency in the grass-snow task--in which a child points to a green card when the experimenter says "snow" and a white card when the experimenter says "grass". Experiment 1 (n =…

Examined whether spatial classification is discovered during play and if external products of play lead children to use space to represent similarity. Found through two experiments--a longitudinal study of four children's classification behaviors, and the examination of play behavior with two types of objects--that comparison of different kinds…