LINGUIST List 3.972

Thu 10 Dec 1992

Calls: Commentators on Brain, Language & Evolution

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1. "Stevan Harnad", Brain, Language & Evolution: BBS Call for Commentators

Below is the abstract of a forthcoming target article by R. Dunbar on
cortex, language and evolution. It has been accepted for publication in
Behavioral and Brain Sciences (BBS), an international,
interdisciplinary journal that provides Open Peer Commentary on
important and controversial current research in the biobehavioral and
cognitive sciences. Commentators must be current BBS Associates or
nominated by a current BBS Associate. To be considered as a commentator
on this article, to suggest other appropriate commentators, or for
information about how to become a BBS Associate, please send email to:

harnadclarity.princeton.edu or harnadpucc.bitnet or write to:
BBS, 20 Nassau Street, #240, Princeton NJ 08542 [tel: 609-921-7771]

To help us put together a balanced list of commentators, please give some
indication of the aspects of the topic on which you would bring your
areas of expertise to bear if you were selected as a commentator. An
electronic draft of the full text is available for inspection by anonymous
ftp according to the instructions that follow after the abstract.
____________________________________________________________________

CO-EVOLUTION OF NEOCORTEX SIZE, GROUP SIZE AND LANGUAGE IN HUMANS

 R.I.M. Dunbar
 Human Evolutionary Biology Research Group
 Department of Anthropology
 University College London
 London WC1E 6BT

KEYWORDS: Neocortical size, group size, humans, language,
Macchiavellian Intelligence

ABSTRACT: Group 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.