Tone of Voice and Mind : The Connections between Intonation ...

6 Chapter 1
ple, but saw the behavioral differences between man and monkey as indicating
a huge gap, regardless of whatever structural similarities the biologists had discovered.
Already in Darwin’s era and even more so today, it is fully apparent
that there are links, similarities and common threads between the most sophisticated
of human linguistic/manual talents and the seemingly quite different
grunts and squeals of dolphins, the singing of songbirds and the twig and rock
handling of apes. Yes, we are all inhabitants of one biological world – cousins
in an undeniable, scientifically-sound, evolutionary sense, but it is not false
pride that makes us think the differences between a gorilla and a chimpanzee
are modest and those between them and us are tremendous. And the sources
of those differences are, above all else, language and tools.
Now ask a neuroscientist what the brain is doing during language- or toolusage.
Again, there are many things to consider, fashionable and unfashionable
topics, new and old methodologies, and personal research interests of various
kinds, but let us start at the top: What is the single, most-outstanding fact about
brain function during speech or goal-directed manual activity? The answer is
unambiguous and no longer controversial: the left hemisphere is dominant.
It is dominant for most people most of the time for the most basic language
functions, and it controls the hand favored for undertaking precise manual
manipulations of the external world. Issues concerning left-handers, special bimanual
skills and the language-related functions of the right hemisphere must
be addressed in any complete account of human brain functions, but the first
and most firmly established fact is that the left hemisphere is the dominant
work-horse for motor control during these crucial, quintessentially human behaviors.
To ignore that one fact at the outset of an examination of the human
brain is to throw the entire discussion out of proper perspective.
A good example of the kind of hemispheric asymmetry found in brainimaging
studies during language functions is shown in Figure 1-1. The reality
of bilateral activation during word repetition and passive listening to words is
perhaps the single clearest result (Figure 1-1A and B), but in all three conditions
the activation of the left hemisphere is significantly stronger than that
of the right hemisphere (the light areas within the darkened regions being the
most highly activated).
The cerebral asymmetry underlying language functions is of such fundamental
importance that the following chapter will be devoted entirely to that
one topic, but it is relevant to note here that the general notion of differential
functions of the cerebral hemispheres in man is well-established, principally
from decades of observation and research in the field of neurology. For various
reasons, the “left-brain, right-brain” story has been exaggerated in certain