Language Evolution and Computation Bibliography

The social hypothesis for language origins is based on the claim that primates use social grooming to bond social groups, and the time available for grooming has an upper limit due to the demands of foraging and food processing. The grooming time is a linear function of group size in both primates and birds so it sets an upper limit to the size of community that can be integrated using the conventional primate mechanism. One of the researchers suggested that language represented a phase shift in communication that allowed this particular glass ceiling to be breached, making it possible for hominins to evolve significantly larger groups than those found among primates. Another researcher showed that the vocal repertoire of the chickadee becomes structurally more complex as group size increases. These findings suggest that the vocal repertoire can become more complex in order to provide a supplementary mechanism for social bonding. The correlation between brain size and group size in primates implies that the first stage of vocal complexity must have occurred with the appearance of the genus Homo around 2 million years ago. The putative demands of instruction in tool manufacture would imply that full-blown language would have evolved at this stage, whereas the social hypothesis requires only an extension of natural primate vocal communication with full grammatical language evolving later.

oup size is a function of relative neocortical volume in nonhuman primates. Extrapolation from this regression equation yields a predicted group size for modern humans very similar to that of certain hunter-gatherer and traditional horticulturalist societies. Groups of similar size are also found in other large-scale forms of contemporary and historical society. Among primates, the cohesion of groups is maintained by social grooming; the time devoted to social grooming is linearly related to group size among the Old World monkeys and apes. To maintain the stability of the large groups characteristic of humans by grooming alone would place intolerable demands on time budgets. It is suggested that (1) the evolution of large groups in the human lineage depended on the development of a more efficient method for time-sharing the processes of social bonding and that (2) language uniquely fulfills this requirement. Data on the size of conversational and other small interacting groups of humans are in line with the predictions for the relative efficiency of conversation compared to grooming as a bonding process. Analysis of a sample of human conversations shows that about 60% of time is spent gossiping about relationships and personal experiences. It is suggested that language evolved to allow individuals to learn about the behavioural characteristics of other group members more rapidly than is possible by direct observation alone.