The concept of dimensions in developmental research.

In the present article, the terms attribute, concept, and category were deliberately used to demonstrate how such terms share a common meaning, at least at one level. This is precisely the level at which interpretive misunderstandings seem to abound. The misunderstandings are not limited to any group of theorists, but apply equally to many of us. Actually, the problem is not very different from that which exists for similarity. In an extensive analysis of the similarity construct, Gregson (1975) remarked that one reason for its popularity was that the lack of a precise definition could be "dangerously versatile." Versatility at the expense of precise definition does not improve either predictability or our understanding of complex developmental processes. That understanding is our goal, and if the suggestions we have made lead to more clearly defined research designs and more consistent results, our goals shall have been achieved.