(1) Arguments Based upon the History of the Brain and Skull
In contrast to the first section of this chapter , in which attempt were discussed to deriver the biological origin of language from a comparison of animal communication , we shall now deal with efforts to reconstruct language history through a reconstruction of brain history .
The brain does not fossilize. Therefore , its history is based on secondary indications; either by a comparison of the brains of present-day animals. or by a study of the bony enclosure of the brains of extinct forms. We must examine these two sources individually.
(a) Comparison with Brain Contemporary Animal .form earlier discussion In this chapter it is obvious that we need not compare the brain of any other species but those of primate, because the hope of encountering behavioral mechanisms that are directly related to human language fades with phylogenetic distance to man .
There is fair agreement on the relationship between species within the order so that we may confine ourselves to the family most closely related to us ,namely the great apes (Pongidae) .Unfortunately there are still vast gaps in our knowledge of the comparative neuron-anatomy of these forms . the literature on cerebral cortex (von Bonin and Bailey ,1961),basal ganglia(Feremutsch,1961),thalamus(Feremutsch,1963),and autonomic nervous system(Werte,1962)has recently been reviewed and the general phylogenetic trends are discussed there (see also Connolly,1950 and Starck,1965). However, the history of the human brain is far from clear.
Many aspects, and perhaps the most important ones for an understanding of language, remain completely unexplored from a comparative point of view; for view; for instance, the connectivity between cells and cell aggregates.
Furthermore , not all details of the brains examined fall into a linear order of evolution because we are not dealing with primitive , primordial but contemporary and adapted brains.
Some of the peculiarities of the human brain are predictable on the basis of allometry and may therefore be attributed simply to general growth factors instead of to behavioral specializations. The greatest problem in this connection arises from the uncertainty about neurological correlates of language.
This has been pointed out in detail in Chapter Two and Five. It not at all clear that the capacity for language depend on any grossly observable structural peculiarity of the brain — not even the central region of the left cerebral cortex because if this part of the brain is removed surgically early enough in life, language may develop without impairment though specializations of other areas.
Thus it is perhaps only molecular structure which affects function, especially relative speeds of conduction I various parts of fiber-system, that is relevant to brain history of language capacity .at the present time nothing is known about this .
There are some very general, methodological questions regarding the usefulness of comparative neuro-anatomy for an elucidation of the phylogenetic emergence of behavior . In a sense species make different “use” of particular brain structures in the elaboration of their species-specific behavior.
The anatomy of the visual system of mammals differs quantitatively rather than qualitatively .
However ,the destruction of large parts of the area striata appears to have different consequences for chimpanzee than for cats; and the peculiarities of pattern perception and the recognition of similarities characteristic for a given species can never be explained through neuron-anatomy . this type of phenomenon makes it difficult to say that ”language could only have come about after a certain type of fiber-connection had developed or a given cortical area had expanded .” Language is the end-product of many interacting processes depending upon a variety of cerebral mechanisms.
But the now-existing associations of language with central-nervous-system peculiarities do not meam an evolutionary inevitable and necessary relationship. Similar behavior might have come about in different combinations of ways .
Earlier forms of communication might have implicated other brain characteristics.
It is an ad hominem argument to say that language is “due” to a given brain development , just as it would be inaccurate to say that man is a poor swimmer because of his lack of fins ,scales, and fish brains .this is not the reason (many animals live in water without these attributes).there is no other reason but that phylogenetic history of man did not adapt him for aquatic life.
We may say that today the capacity for language is dependent upon a human brain; but we cannot write a causal history of this relationship (see also Overhage,1959).
In short, the evolutionary history of man’s cerebral capacity for language cannot be easily elucidated by examining the brains of other living species .Probably man was separated from other primates long before his brain began to evolve in the direction of the language-pre-requisites.
1.Arguments Based upon the History of the Brain and Skull1. 根據腦和頭顱骨的論據
2.deal with efforts to reconstruct language history through a reconstruction of brain history經由動物腦的重組歷史致力於重組語言發展史
3.Comparison with Brain Contemporary Anima比較現代動物的腦l
4.There are some very general, methodological questions regarding the usefulness of comparative neuro-anatomy for an elucidation of the phylogenetic emergence of behavior一些非常一般的比較神經解剖學的有用性與行為演化樹的方法學的問題
5..Earlier forms of communication might have implicated other brain characteristics. .早期溝通形態可能和腦部特徵有關
6.The evolutionary history of man’s cerebral capacity for language cannot be easily elucidated by examining the brains of other living species