Language, Tools and Brain: BBS Call for Commentators

[Stevan Harnad]

Below is the abstract of a forthcoming target article to appear 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:

harnad at clarity.princeton.edu  or harnad at pucc.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 are selected as a commentator.
____________________________________________________________________

      Language, Tools, and Brain:  The development and evolution of
                       hierarchically organized sequential behavior

                     Patricia Marks Greenfield
                     Department of Psychology 
                     University of California, UCLA
                     Los Angeles, CA 90024-1563
                electronic mail: rygreen at uclasscf.bitnet

Abstract: During the first two years of life a common neural substrate
(roughly, Broca's area) underlies the hierarchically organized
combination of elements in the development of both speech and manual
action, including tool use. The neural evidence implicates relatively
specific cortical circuitry underlying a grammatical "module."
Behavioral and neurodevelopmental data suggest that the modular
capacities for language and manipulation are not present at birth but
come into being gradually during the third and fourth years of life.
An evolutionary homologue of the common neural substrate for language
production and manual action during the first two years of human life
is hypothesized to have provided a foundation for the evolution of
language before the divergence of hominids and the great apes. Support
comes from the discovery of a Broca's area analogue in contemporary
primates. In addition, chimpanzees have an identical constraint on
hierarchical complexity in both tool use and symbol combination. Their
performance matches that of the two-year-old child who has not yet
developed the differentiated neural circuits for the relatively
modularized production of complex grammar and complex manual
construction activity.