hominid ancestors,the australopithecines.Minimally,they should have
possessed a rich repertoire of calls employed in social contexts and used
especially to express emotions.That is,rather than being referential as
words are,their calls (entailing pitch changes) would have been gener-
ally emotive and affective.In addition,australopithecines probably did
a certain amount of chorusing and drumming,similar to African great
apes.It is possible that early hominids were also characterized by gender
differences in their auditory communications,although no evidence
pertaining to this is found in the fossil record to date.In short,modern
linguistic and musical abilities probably evolved from beginnings such
as these.But how,why,and when?
A hint at how humanlike auditory communication evolved may be
glimpsed by examining neurological substrates for auditory-vocal com-
munication in people and other animals.As documented,humans are,
above all else,highly lateralized for processing language and music,
respectively,to left and right hemispheres.Unlike any other animal,
including nonhuman primates (McGrew and Marchant 1997),Homo
sapiensis also highly lateralized for right-handedness,the neurological
substrate of which is adjacent to Broca’s speech area in the left hemi-
sphere.What about other aspects of brain lateralization in animals? Con-
trary to previously held beliefs,other species are also neurologically
lateralized for a variety of functions,including circling behaviors in
rodents,production of songs in birds (left hemisphere dominant),and
processing of socially meaningful vocalizations (left hemisphere domi-
nant) as well as certain visual stimuli (dominance varies with task) in
some monkeys (Glick 1985;Falk 1992a,b).Furthermore,it is the rule
rather than the exception for these asymmetries to be sexually dimor-
phic with respect to side of dominance and/or frequency of occurrence
(Glick 1985).From these data,we may surmise that complex human
auditory communications evolved as hominid brains enlarged beyond
the ape-size volumes characteristic of australopithecines (Falk 1992a,b),
in conjunction with elaboration of basic cortical lateralization that was
inherited from very early mammalian ancestors.
If one can discern a basic function for brain lateralization in animals,
one might have a glimmer about why language and music eventually
evolved in humans.In this context,it becomes important to explore
Darwinian natural selection by assessing reproductive advantages that
are gained by individuals or species as a result of lateralization.Within
this framework,the gender differences in brain lateralization that char-
acterize many species (Glick 1985) are tantalizing.For example,a study
in the house mouse (Ehret 1987) offers an important clue about the pos-
sible evolutionary history of the neurological substrates that facilitate
enhanced language skills in women relative to men (Falk 1997).211 Hominid Brain Evolution and the Origins of Music