BRAIN: HUMAN VS ANIMAL
المؤلف:
John Field
المصدر:
Psycholinguistics
الجزء والصفحة:
P44
2025-08-03
341
BRAIN: HUMAN VS ANIMAL
It may be that human beings have developed language when other species have not because the human brain operates in distinctive ways. Hence an interest in discovering how our brain differs physically from those of other creatures, including other primates.
The critical difference is not one of brain capacity: elephants and whales have larger brains than human beings, mice have a greater brain/body ratio and a number of rodents and small mammals have denser neural connections. The discussion therefore focuses on whether the human brain is different in certain of its components, in its structure and in the way it develops.
It was once surmised that a locus for an innate language faculty might be found in the left hemisphere of the human brain. It is in this hemisphere that, for most humans, functions involving syntax and lexis appear to become lateralised, and it was noted that the left hemisphere is often larger than the right. However, the same kind of left-hemisphere dominance has been found in several other species, including birds.
The operation of language is currently envisaged as being very widely distributed in the brain, with many different areas (including some in the right hemisphere) contributing cognitive and motor sub skills. Attention has focused on specific areas of the human brain which are markedly larger relative to the whole organ than the equivalent areas in other primate brains.
The cortex is proportionately much greater in human beings. This is the area that controls complex operations including making connections with stored information, analysing input and co ordinating sophisticated muscular movements.
Human pre-frontal areas are up to six times bigger than those of chimpanzees in relation to body size. These areas appear to be responsible for recognising similarities between objects and grouping them into categories. Damage there may limit the ability to perform tasks that involve seeing things from the perspective of others.
The human cerebellum at the base of the brain is much larger, relative to brain size, than in other species. It co-ordinates a range of highly automatic muscular movements.
In human beings, a greater proportion of the motor area is given over to the control of mouth, tongue and jaw. Human motor areas also exercise a high degree of control over the larynx, which regulates the passage of air in breathing and speech. In other species, the operation of the larynx is mainly or entirely controlled by the lower parts of the brain, which means that it is largely involuntary. Control of the larynx enables us to co-ordinate breathing and vocalisation and is an important factor in the ability to produce speech.
What also appears to distinguish human beings is brain growth in infancy. The ratio of brain weight to body weight resembles that of other mammals pre-natally but, after birth, brain growth in humans greatly outstrips body growth as compared with other primates. This suggests a very different evolutionary history from other species, one which may uniquely have favoured the development of the sophisticated cognitive processes which are a condition of language.
See also: Animal communication, Evolution of language, Vocalisation
Further reading: Deacon (1997)
الاكثر قراءة في Linguistics fields
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