Surveying hypotheses for the evolution of language

Tecumseh Fitch,
University of St. Andrews

wtsf@st-andrews.ac.uk

Scientific consideration of the evolution of language has reached a
stage where both the number of hypotheses and the mass of data available
to test them demands a dispassionate survey of multiple available
hypothesis.  Speculative hypotheses about the evolution of any single
component of the language faculty abound, but the task of constructing a
coherent account of the evolution of the many elements underlying
language in a broad sense is far from trivial.  Plausible hypotheses
must be consistent with both available comparative, fossil, linguistic
and neural data, and accepted neo-Darwinian theory.  Features of
language to be accounted for include speech production, especially vocal
imitation, meaning, and complex syntax.  Evolutionary forces to be
reckoned with include natural selection, sexual selection and kin
selection on either the communicative or the cognitive benefits of
language.  Constraints to be satisfied include compatibility with modern
evolutionary theory, known hominid phyogeny, existence of plausible
precursor abilities in animals, and conservatism of the vertebrate brain
(and genome). 

A brief survey of single-cause hypotheses suggests that none are
adequate to account for all features of language.  Thus some variant on
a two-stage hypothesis, incorporating selection on an intermediate
"protolanguage", seems necessary.  I consider four such hypotheses in
more detail: Condillac's gestural origins hypothesis (Corballis, 2002),
Bickerton's asyntactic protolanguage hypothesis (Bickerton, 1995),
Merlin Donald's mimetic stage (Donald, 1993), and Darwin's prosodic
protolanguage hypothesis (Darwin, 1871).  The focus by many scholars on
sexual selection for language evolution has drawn attention away from
kin selection as a much more plausible alternative for the evolution of
complex propositional meaning.  Although at present none of these
hypotheses is perfect or complete, I conclude that Darwin's hypothesis,
with some updating (see Fitch (in press)), along with Donald's, provide
the best fit to available data, and leave the fewest questions
unanswered.  More importantly I conclude that such multi-hypothesis
comparisons will help bring structure and unity into the developing
discipline of language evolution. 

References

Bickerton, D.  1995.  Language and human behavior.  Seattle: University
of Washington Press. 

Corballis, M.  C.  2002.  From Hand to Mouth: the origins of language. 
Princeton: Princeton University Press. 

Darwin, C.  1871.  The Descent of Man and Selection in Relation to Sex. 
London: John Murray. 

Donald, M.  1993.  Origins of the Modern Mind.  Cambridge,
Massachusetts: Harvard University Press. 

Fitch, W.  T.  in press.  Evolving Honest Communication Systems: Kin
Selection and "Mother Tongues".  In: The Evolution of Communication
Systems: A Comparative Approach (Ed.  by Oller, D.  K.  & Griebel, U.). 
Cambridge, Massachusetts: MIT Press.