Spatial distinctiveness effect in categorisation

The aim of the present study was to show that the probability of an item being retrieved is proportional to its spatial distinctiveness, and that this distinctiveness effect can be obtained in an implicit memory task. The participants were presented with two phases in which they had to categorise pictures of objects as either “kitchen utensils” or “do-it-yourself tools”. In our encoding phase, the pictures were successively presented in different positions on the screen. The positions were arranged in one of two different configurations: a “distinctive condition” in which the pictures were placed in two circles, one central and one peripheral, such that the distance between the pictures was greater when they were in a peripheral position than in a central position, and a “nondistinctive” condition, in which the distance between the pictures was constant irrespective of their central or peripheral position. In the test phase, the same pictures were presented for categorisation, mixed with new pictures at the centre of the screen. The results clearly confirmed our expectations.