Dean Falk

Abstract

Recent positron emission tomography and functional magnetic resonance

imaging studies show that the cortical substrates for both language and music

depend on widely distributed networks that in some cases overlap; use both sides

of the brain, but are dominated by opposite hemispheres; and differ similarly in

men and women. Because music and language are so neurologically intertwined,

it is hypothesized that they evolved together as brain size increased during the

past two million years in the genus Homo. Comparative behavioral and neuro-

logical data from a wide range of animals, together with information about brain

evolution from the hominid fossil record, are incorporated into discussion of

how, why, and when hominids evolved their musical and linguistic abilities.

Because no chimpanzee has ever spoken a sentence, post-Darwinian

scientists have been fascinated with the human ability for speech and

pondered its origins. Consequently, much is known about the neurolo-

gical substrates for language, and a robust literature is available about

its hypothetical evolution. What has been forgotten, however, is that no

chimpanzee has ever played the violin. The neurological processing of

music has just begun to be explored using available medical technology

to image the brains of musicians as they perform. The first part of this

paper provides information about the neurological substrates for lan-

guage and music, and explores the relationship between the two. In the

second part of this chapter, this neurological information is synthesized

with paleoneurological data from the hominid fossil record, and incor-

porated into discussion about how, why and when elaborate auditory

communications evolved in the human primate.

Neurological Substrates of Language and Music

Cortical Bases of Language

Recent applications of medical imaging technology using positron emis-

sion tomography (PET) and functional magnetic resonance imaging

(fMRI) have made it possible to assess brain activity in human subjects

as they perform specific cognitive tasks. Although many investigations

have explored the specific neurological areas involved in language-

related activities, few have focused on musical skills. Those that have,

however, are very telling and even surprising, because they reveal that

the neurological substrates for both endeavors overlap to a larger degree

than one might have expected given the well-known fact of the left hemi-

sphere’s primary involvement with language and the right hemisphere’s

with music. In other words, despite their different dependence on the left

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Hominid Brain Evolution and the Origins of Music