Kieran Egan's "What Does Piaget's Theory Describe?" answers the title question by unearthing an increasing amount of data which cannot be accounted for by Piaget's theory of cognitive development. Because one of the very weakest and least supported parts of Piaget's theory has had the greatest impact on education, Egan considers it most important to set the record straight. The Piagetians' assertion--that cognitive development is dependant upon the successful fulfillment of sequentially complex developmental tasks which are resistant to learning--has had a great impact on education because it is quite specific with regard to what a child can or cannot do at any particular developmental level. In other words, to the Piagetians, it is futile to teach the principle of conservation to a child who is in a pre-operational stage.
Egan is skeptical but objective in his attempt to find what Piaget's theory really describes. He claims that he may be somewhat biased because he is a non-psychologist looking at a psychological theory, not through the language of the theory, but rather through the data, into the theory. The irony in his comment about being biased is apparent in his determination to test all empirical evidence as a scientist does, by applying a theory to different situations, putting it in a different context, or seeing behaviour, not through the language of theory, but as behaviour unimpeded by theoretical preconceptions. It is to Egan's credibility that he, a non-psychologist, would evaluate Piaget's work without any professional agenda. He is only interested in determining the validity of Piaget's research for educators, as those who would be most influenced by a theory which states that it is either futile, or a "great disservice" (Karmiloff-Smith, 1978, cited in Egan, 1982, p. 19) to teach a child concepts which are not in lockstep with developmental theory.
Egan (1982) spends a good deal of time evaluating the cont...