na in mammalian vocal production
possibly interesting to list members:
Animal Behaviour
Vol. 63, No. 3, March 2002 pp. 407-418
Calls out of chaos: the adaptive significance of nonlinear phenomena in
mammalian vocal production
W. Tecumseh Fitch, J=FCrgen Neubauer, Hanspeter Herzel
Abstract
Recent work on human vocal production demonstrates that certain irregular
phenomena seen in human pathological voices and baby crying result from
nonlinearities in the vocal production system. Equivalent phenomena are qui=
te
common in nonhuman mammal vocal repertoires. In particular, bifurcations an=
d
chaos are ubiquitous aspects of the normal adult repertoire in many primate
species. Here we argue that these phenomena result from properties inherent=
in
the peripheral production mechanism, which allows individuals to generate
highly complex and unpredictable vocalizations without requiring equivalent=
ly
complex neural control mechanisms. We provide examples from the vocal
repertoire of rhesus macaques, Macaca mulatta, and other species illustrati=
ng
the different classes of nonlinear phenomena, and review the concepts from
nonlinear dynamics that explicate these calls. Finally, we discuss the
evolutionary significance of nonlinear vocal phenomena. We suggest that
nonlinear phenomena may subserve individual recognition and the estimation =
of
size or fluctuating asymmetry from vocalizations. Furthermore, neurally `ch=
eap'
unpredictability may serve the valuable adaptive function of making chaotic
calls difficult to predict and ignore. While noting that nonlinear phenomen=
a
are in some cases probably nonadaptive by-products of the physics of the
sound-generating mechanism, we suggest that these functional hypotheses pro=
vide
at least a partial explanation for the ubiquity of nonlinear calls in nonhu=
man
vocal repertoires. Copyright 2002 The Association for the Study of Animal
Behaviour
Correspondence: W. T. Fitch, Department of Psychology, Harvard University, =
33
Kirkland Street, Room 982, Cambridge, MA 02138, U.S.A. (email:
H. Herzel and J. Neubauer are at the Institute of Theoretical Biology, Humb=
oldt
University, Invalidenstrasse 43, D-10115 Berlin, Germany.
http://www.idealibrary.com/servlet/doi/10.1006/anbe.2001.1912
________________________________________________________________________
________________________________________________________________________
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
|