The Origins of Intelligence (review)

The Origins of Intelligence, by Sue Taylor Parker and Michael L. McKinney. Baltimore, MD: Johns Hopkins University Press. 1999. 404 pp. CDN$81.50; USD$55.00.

The Origins of Intelligence comprises 13 chapters in two parts. Part I concerns ontogeny of cognition within a Piagetian framework. Part II focuses on phylogeny and evolutionary biology. Part I and chapters 9, 10, and 11 were written by Parker. McKinney contributed chapters 8 and 13. Only Chapter 12 is coauthored. The book is stylistically quite academic, and at points cumbersome. There are an objectionable number of errors: of fact, of spelling--a proper editing could have obviated many of these annoying flaws.

The purpose of the book is to trace the origins of cognitive abilities. Comparisons throughout are between human children and nonhuman primates, mostly the apes. The Piagetian theory and methodology are supplemented by Perner's (1991) framework when the discussion turns to the theory of mind in the chapter on social cognition. The overall hypothesis is presented in the preface and introduction and identified as 'radical' in that it confronts and dismisses the evolutionary process of the retention of juvenile traits in the adult known as neoteny (i.e., juvenilization) as the means by which cognitive abilities developed sequentially for primates. Rather, it was "adultification," the progressive extension of adult stages, that facilitated this development. These concepts are situated within evolutionary biology and given extensive treatment. McKinney recently (1990) coauthored a seminal work discussing heterochrony--changes in rates of growth and development within the evolutionary context. His contribution, then, is a reiteration and exegesis of the process by which hominid abilities emerged. Major excursions to intellectual history, cladistics, anatomy, neuroanatomy, and behavior are made to develop the matrix for the thesis. It is an ambitious and impressive journey, interesting, and provocative. The size of the project, however, sets its own limitations.

Trying to standardize developmental progression across the Order is understandably a priority, but virtually impossible since there is a dearth of Piagetian studies across the Order. The use of Piaget as a universal comparative structure is reasonable because it is so well known, despite the development of alternative models of cognition (e.g., Gopnik 1996), and despite the fact that the sensorimotor period--essential to this work--is currently being reviewed as knowledge of cognitive development in children increases (Decarie et al. 1996; Mueller et al. 1998). The debate in neo-Piagetian discourse over what influences development, biology or social environment, has received a new twist with the recent publication by Deaner et al. (2000) indicating that such studies are methodologically flawed, so that there may not be a distinction between these 'forces' in evolutionary development. Certainly the evidence of enculturation (p. 159) depends on having a culture. Since the 1970s, 'culture' has become increasingly acceptable as a term to describe the means by which nonhuman primates--especially great apes, especially chimps--live. While the authors contest some details of other scenarios concerning the origin and development of culture (pp. 276 ff.), they agree that it lies significantly within the domain of the great apes. A good number of primatologists who watch monkeys will disagree as I outline further below.

Generalizing at different taxonomic levels (subfamily versus genus) unnecessarily confuses the phylogenetic inquiry. Further distortion is possible when categories as vast as "apes," "cebus," and "macaque" (p. 54), or even worse "monkeys" (e.g., p. 121) are used when discriminating cognitive abilities. The text on p. 265 says that Table 9-4 will compare macaques, great apes, humans, and hominid teeth with developmental stages, but does not. There are no hominids in the table, yet reference is made to the table for Homo "erectines" (a vague and generalized nomenclature). The point of the table is to compare dental development with cognitive stages. The capuchins are important to the development of the argument on heterochrony (but are not in the table), since their abilities, being out of phase with the rest of the New World monkeys as well...