To examine interactive effects of conceptual and labeling levels on categorization as a function of age, kindergartners, 2nd, and 4th graders were required to judge whether two instances (drawings) in each pair of food or animals belonged to the same group or not. Three conceptual levels of pairs were provided : lower of basic (banana 1-banana 2), middle (banana 1-apple), and higher (bnana 1-cabbage) pairs. After the one instance in each pair (banana 1) was labeled as lower or basic ("banana"), middle ("fruit"), or higher ("food") levels by the experimenter, the subjects were asked to the same question. Thus three conceptual levels ran across three labeling levels. Children's categorization assessed by "same" judgements was facilitated when the pairs with higher conceptual level were labeled by the higher level, whereas it was inhibited when the pairs with middle conceptual level were labeled by the lower level. These facilitating and inhibiting effects increased with age. The findings were discussed by activation of categorical knowledge, limitation of knowledge domain, and equivalence and difference of two instances.
