Social and socio-
Ontogeny and symbolism
The ontogeny and evolution of the brain, cognition, and language
Brain maturation data provide no factual support for the common view that the human brain is a neotenous organ. Nor can the human brain be considered unusually altricial at birth. Limited recapitulation, however, does characterize human neural maturation. Specifically, the neocortical association areas are late to mature and have demonstrated the greatest phylogenetic expansion. This parallel provides a basis for attempts to unravel the evolution of language phylogeny by examining its ontogeny. In particular, the enlargement of the neocortical association areas has most probably provided the quantitatively based, hierarchical mental constructional skills which Case suggests underlie the maturation of human intelligence and which appear to distinguish human and ape tool-using and communication behaviours. These considerations suggest that Case's quantitative developmental framework provides a logical base for theories of language evolution. In Case's framework, the development of intelligence is not only quantitative and hierarchical in nature, it is also interactive. Object-manipulation skills, social behaviour, and language mature in a synchronous and mutually facilitatory fashion. This implies that not only brain size, but also cultural remains such as tools, shelters, or evidence of feeding techniques can provide important clues to the evolution of language. On the basis of these considerations, language, like tool-use and brain size, is postulated to have evolved slowly over several million years. With each cognitive and linguistic advance, new foraging and social interactive skills would have arisen. It is suggested that, as in ontogeny, language evolution began in mother-child dyads with the communication of simple needs and desires by one- to two-'word' utterances. As grammatical skills increased, hominids became capable of discussing co-operative endeavours and/or absent 'rendezvous' or other sites. At still later stages, linguistic skills permitted the discussion of animal and plant ecology and, finally, the prediction of seasonal events.