The theme of our lecture today¹ is the problem of perception in child psychology. You know, of course, that no chapter of contemporary psychology has been as fundamentally rewritten in the past 15–20 years as that concerned with the problem of perception. You know that the skirmish between the representatives of the old and the new psychology has been more intense here than in any other domain of research. Nowhere has the structural tradition placed its new conceptions and experimental research methods in such sharp opposition to the old, associative tradition. If we consider concrete experimental material, the chapter on perception has clearly been more extensively rewritten than any other chapter of experimental psychology.