As children grow older they show an increasing preference for classifying objects on the basis of shape rather than color. To clarify the nature of this "dimension preference," children of ages 3 l/2 to 6 1/2 years were given a method of triads test of dimension preferences, followed (after a week's delay) by a component selection task. The most notable results were these: (1) Children below and above the median age differed in frequency of shape preference; (2) For children below the median age, higher component selection test scores were observed for the preferred dimension; and (3) No age difference was found in the relative magnitudes of the component selection scores. The results suggest that a "preference" for a particular dimension does not necessarily indicate a high degree of selective attention to that dimension. Also, the age difference in children's dimension preferences may be attributable to factors unrelated to selective attention. (Author) (16pp.)