vocalizations may not approach the referential power of our own words,
either in terms of the kinds of objects and events that can be referred to
(imagined objects,future states) or the mental states that accompany
their production (beliefs,intentions),they may represent a sufficiently
advanced system to warrant classification as a precursor.This position
makes the assumption that part of our language faculty was constructed
out of an evolutionarily antecedent system.
Some,such as Deacon (1997),consider this position fallacious because
language is not an end point.It is,however,a species-specific communi-
cation system driven by a species-specific brain.Therefore,in the same
way that we can look for precursors to a humanlike eye or heart,we can
look for precursors to a humanlike language.To date,most consider the
evidence for language precursors to be pathetic (see Bickerton 1990,this
volume).I would like to propose that before we lay such issues to rest
we tighten up our notion of precursor and refine our understanding of
animal referents and the thoughts that underlie them.Whether or not
the vocalizations of primates capture the status of linguistic precursors
requires a more precise articulation of both the conceptual tools under-
lying them in humans and the kinds of selection pressures that would
have been necessary to evolve such a system during primate history.Calls of the Lopsided Brain
Several neuroscientists (Corballis 1991; Hellige 1993;Hiscock and
Kinsbourne 1995) maintain that although nonhuman animals show
evidence of neuroanatomical asymmetries,and even some evidence of
behavioral asymmetries,only humans have extensive differentiation of
cognitive function between the hemispheres,with evidence of asymmetry
at the population level.Specifically,most humans have left hemisphere
dominance for language processing and right hemisphere dominance for
spatial reasoning,emotional perception,and expression (see reviews in
Bradshaw and Rogers 1993;Hellige 1993;Davidson and Hugdahl 1995).
As research in this area has developed since the late 1980s,however,it
is clear that the original claims regarding hemispheric dominance were
far too general,that dichotomies for right and left hemisphere domi-
nance covered up important overlap in function (Efron 1990;chapters
in Davidson and Hugdahl 1995).For example,although the left hemi-
sphere is dominant with regard to semantics and formal combinatorial
properties of language (syntax),the right hemisphere appears dominant
for processing paralinguistic features of language such as melody and
changes in pitch (Ross et al.1988;but see Peretz and Babai 1992).Thus,
the right hemisphere is certainly not silent during language processing,88 Marc D.Hauser