THE HEURISTIC VALUE OF WERNERS COEXISTENCE CONCEPT OF DEVELOPMENT

Werner's co-existence concept of development accounts for expectable a nd consistent between group differences in ontogenesis. A co-existence concept of development, rather than a replacement concept of developm ent, also addresses variabilities within individual children and adult s in the same domain. This study examined both ''replacement'' and ''c o-existence'' concepts of development in the domain of illness. Both c oncepts of development accounted for the fact that no child exhibited abstract concepts of illness. However, only a co-existence concept of development can account for the fact that most college students demons trated magical and concrete concepts of illness.