1 - The mosaic evolution of cognitive and linguistic ontogeny

Summary

Before we can properly consider the relations between language and cognition from the perspective of a comparative primatology, we will need to establish some fundamental points about the similarities and differences of cognitive development in the different species. Towards the end of the chapter I shall then return to the central issue, and show that the comparative developmental data demonstrate that there can be no very intimate interaction between language and cognition in early ontogenesis - cognition leads.

A popular evolutionary theory of human cognition, neoteny, has it that we are developmentally retarded, allowing a greater period of plasticity for the acquisition of culture (e.g. Gould 1977; Montagu 1981). The comparative data, we shall see, do not support the neoteny theory. If anything, humans' cognitive development is precocious as compared to that of other primate species. Of course, this in no way denies that “changes in the relative time of appearances and rate of development for characters already present in ancestors” (the modern neo-Haeckelian definition of heterochrony proposed by Gould 1977:2) is a valid biogenetic law of the evolution of cognitive development (see McKinney & McNamara 1991; Mayr 1994; Langer & Killen 1998; and Parker, Langer, & McKinney 2000, for updated analyses). One product of such timing changes is mosaic organizational heterochrony of ancestral characters, whether morphological such as the body or behavioral such as cognition. With human children, this initial nonverbal and nondirective procedure was followed by progressively provoked probes.