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Part I

Part II

Part III

Part IV

Part V



     

 Vol.4: Evolution or Creation?

Chapter 2

The Human Brain: Its Size and Its Complexity

     IF INDIVIDUAL features of human anatomy and physiology are considered separately, and are compared separately with parallel features found in the animal world, a fairly good case might be made out for the derivation of man by evolution from some animal, presumably among the primates. But if the features of man's anatomy and physiology are taken as a whole, viewed in relation to each other and seen as an integrated unity, the situation is rather different. Virtually every one of the anatomical and physiological features listed in the previous chapter are found singly in rudimentary or developed form somewhere else. And even some of man's characteristic social and cultural forms of behaviour are reflected, randomly distributed, among different species also in rudimentary forms.
     
What I am particularly anxious to make clear, however, is that no single animal, nor any single species, exhibits these features as a whole. Individuals and species can be found which have one or several of these features, but not all of them. An awareness of these facts will help us to avoid attaching importance to differences in structure, etc., beyond what is proper in the light of the evidence. At the same time, it will help us to see more clearly that it really is the combination of features which has made man such a unique creature.
     
If the same Designer and Architect formed the animals as formed man, it should surely not be at all surprising to find that successful "solutions" to problems faced by all living things are used over and over again in different contexts. And this is precisely what we do find.
     
All living things are chemically organized according to a single basic pattern involving the same nucleic acids, peptides, and amino acids, though not necessarily making the same selection. In his contribution to the symposium published under the title The Origins

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of Prebiological Systems, Peter T. Mora suggested that the amazing similarity in the biochemical processes of living systems implies that life originated only once. (24)There is, however, an alternative implication: namely, that having designed a perfectly effective biochemical process, the Creator thereafter employed it as a basis for every living form that He created. Uniformity in this respect would therefore just as likely be evidence of a single Architect at work, as evidence of the evolution of a single chance product. In the same vein it should be pointed out that all striated muscle is also built on an almost identical pattern in all living things. In this connection, J. D. Bernal draws the same kind of conclusion that Mora drew: viz., that such "an ingenious device," to use his term, (25) can surely have been invented only once and must therefore have been inherited by all the different phyla from the first prototype, "probably to perform ciliary motion." As in the previous case, it may just as well be evidence of a master design being re-employed many times.
     
When we look at the anatomy and physiology of man, we see plenty of evidence of this re-employment of successful design features already used elsewhere. The similarity of many of the vital organs of living organisms is in no way necessarily evidence of descent. The appearance of almost identical eye structures in the octopus and in mammals should be sufficient demonstration of this fact. Consequently, certain design features in one species that serve a particular purpose may be found in another species in very similar form, yet serving a somewhat different purpose. When we compare man with the animals which are structurally most like him, and are therefore presumed to be most nearly related, we are driven by some compulsive thought process of the human mind to arrange the structures in some kind of ascending or descending order and to assume that this order represents degrees of relatedness. We may tend to do this even when we do not accept the theory of evolution. We make the assumption that a larger brain is a later brain because we recognize that this happens as the infant grows into the adult. We also tend to assume that anything which looks more complex is more complex, because in most man-made products this is the case.
     
And so in considering the relationship between man and the primates from which he is supposedly evolved, it may be well to look into a critical organ (the brain) and a critical anatomical feature (the

24. Mora, Peter T., "The Folly of Probability,'' in The Origin of Prebiological Systems, edited by Sidney W. Fox, Academic Press, New York, 1965, p.45.
25. Bernal,J. D., "Molecular Matrices for Living Systems," in The Origin of Prebiological Systems, ibid, p.79.

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ability to stand erect), and see to what extent the differences are important. And it may be said, in anticipation, that although we do not yet know exactly why the size of the human brain is so much larger than that of the ape brain, we have a somewhat better idea of why man's erect posture is of such great importance. The two combined, however, make all the difference in the world in terms of the potential of man by contrast with that of his supposed nearest relatives.
     
The feeling that brain size or surface complexity is of crucial importance in terms of intelligence or mental capacity and that man excels in both, has plagued anthropological research for almost a hundred years. Indeed, so compelling is this conviction that anthropologists are guilty not infrequently of either doctoring or distorting the evidence in order to close the gap between man and ape, by raising the cranial capacity or brain size of potential missing links, or reducing the cranial capacity of very early man.
     
It will be helpful to have some basic figures, drawn from a number of sources, which will give an overall picture of size ranges of primate brains. Zuckerman gave the following cranial capacities: (26)

Female Chimpanzee 366 + 6.5 cc.
Male Chimpanzee 399 + 7.0 cc.
 Female Gorilla  466 + 10.4 cc.
 Male Gorilla  543 +4.3 cc.
 Pithecanthropus erectus  1026+34.2 cc.

    The Australopithecines, represented by a number of supposedly separate genera (Paranthropus, Pleisianthropus), (27) which were hailed as missing links but are now believed to come a little too late in the geological time scale as currently held, were of particular interest to evolutionists because their cranial capacity was believed to be between 450 and 550 cc., which, combined with their much debated erectness of posture, seemed to fit rather well between other primates and man.
     
Modern man shows an extraordinarily wide range of cranial capacities. There are records of capacities as low as 800 cc. in individuals of normal size (28) though only found among idiots; and it is commonly agreed that man is not mentally normal with a cranial

26. Zuckerman, Solly, "An Ape or the Ape," Journal of the Royal Anthropological Institute, vol.81, parts 1 & 2. 1952, p.63
27. Australopithecines: J. T. Robinson, "The Origins and Adaptive Radiation of Australopithecines," in Human Evolution, edited by N. Korn and F. Thompson, Holt, Rinehart & Winston, New York, 1967, p.296.
28. Ibid., p.284.

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capacity of less than 900 cc. This figure is sometimes referred to as the Cerebral Rubicon for Homo sapiens. (29) Human dwarfs are known with brain volumes which may not exceed 300-400 cc. These are not normal dwarfs but are known as nanocephalic or "bird-brained" dwarfs. Their smaller brain of course means far fewer functioning brain cells even than in many chimpanzees, yet they are quite capable of learning language and although usually mentally defective, their behaviour is still quite specifically human. In referring to these individuals, David Pilbeam remarked, "This clearly underlines the important point that it is brain structure rather than brain size which is so important in species-specific behaviour." (30) I think there is some reason, as we shall see, to question whether even brain structure is important in any specific way, though it may be that the protein composition of the brain substance itself is species-specific.
     
Occasionally one sees the cranial capacity of the gorilla given as 685 cc. (31) which comes close to the minimum for Homo sapiens (although idiotic). It should be noted, however, that this was one single gorilla measurement, and though the figure has been quoted many, many times and often taken as a norm for gorillas, to my knowledge it has never been duplicated. The use of the figure illustrates how strong the temptation is to fill out the series from animals to man. Weidenreich placed the gorilla's cranial capacity at only 620 cc., and he gave the average for the whole anthropoid group as being "only 415 cc." (32)
     
As we have said, brain weights among human beings vary enormously. In giving measurements of brain size for contemporary man, it is customary to use grams rather than cubic centimeters, but for reasons which it is not necessary to enter into here, the two forms of measurement in this case are virtually the same. The average for the adult European male is about 1375 gm. whereas the brain of Turgenev, the Russian novelist, weighed 2021 gm. It was exceeded by that of only two others so far recorded: one was an imbecile. Then there is the record of a labourer whose brain weighed 1925 gm. and a bricklayer, 1900 gm. The brain weight of Gambetta, the famous French statesman, was only 1294 gm., or less than the average

29. Cerebral Rubicon: This phrase was used by A. N. Whitehead, "The distinction between man and animals is in one sense only a difference in degree. But the extent of that degree makes all the difference. The Rubicon has been crossed" (Modes of Thought, 1938; as quoted by W. H. Thorpe, Animal Nature and Human Nature, Methuen, 1974, p.11). See also P. V. Tobias, "Olduvai Bed I Homine with Special Reference to Its Cranial Capacity", Nature, vol.202, 4 Apr., 1964, p.3.
30. Human dwarfs: David Pilbeam, The Evolution of Man, Thames & Hudson, London, 1970, p.202.
31. Clark, W. E. LeGros, "Bones of Contention", Human Evolution, edited by N. Korn and F. Thompson, Holt, Rinehart & Winston, 1967, p.305. In fairness, Clark gives this figure for a, not the gorilla.
32. Weidenreich, Franz, Apes, Giants and Men, University of Chicago Press, 1948, p.10, 11.

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European. A woman's brain is slightly smaller than man's, and the largest woman's brain recorded was 1742 gm. she was insane. Another woman's brain of large size weighed 1580 gm., and she also was insane. (33) It is some evidence of the unimportance of brain size that the brain of Anatole France weighed only 1017 gm. while the brain of Bismark weighed 1807 gm. (34)
     
When we come to review fossil man, we meet with some surprises. While certain of the supposedly earliest fossils fall nicely into place, some of them do not do so. As we have seen, Pithecanthropus erectus was given a capacity of 1026 cc. by Zuckerman but somewhat lower (9001000) by William Howells. (35) The same authority gave a figure for Sinanthropus of 1150 cc. (36) This seems to be in the right kind of ascending scale. But then Solo Man, (37) who was placed only just above Pithecanthropus erectus in the evolutionary scale by Howells, had a cranial capacity of 1300 cc.which is essentially modern man's. Once again the order seems to be "satisfactory," but then something goes wrong. For Solo Man is considered to have been contemporary with Neanderthal Man, and Neanderthal Man had a cranial capacity which in several specimens was in excess of 1625 cc., which is far above modern man. (38) Two other primitive fossil skulls, Wadjak and Boskop, had cranial capacities, respectively, of 15501650 cc. and 1800 cc. which is even higher. (39)
     
Because we happen to have some cultural remains of his which are in every way remarkable, Cromagnon Man is generally considered the high point in the development of ancient Homo sapiens. Yet Cromagnon had a slightly larger brain capacity than Neanderthal 15901660 cc.which is 15 percent larger than ours. (40) It might be doubted therefore (if we are guided merely by cranial capacity) whether modern man is really an advance on his ancestors. Cromagnon could be the high point of modern Homo sapiens, too.
     
The actual significance of brain size is being called into.question, and so also is its structural form or surface complexity. Consider these facts. Julian Huxley was satisfied that the evidence demonstrates that a larger brain is a better learning organ than a

33. Various brain sizes: George Dorsey, Why Behave Like Human Beings, Blue Ribbon Books, New York, 1925, p.11. See also Franz Weidenreich, "The Human Brain in the Light of Its Phylogenetic Development", Scientific Monthy, vol.67, Aug., 1948, p.103-109.
34 Bismark: Stanley Cobb, "Brain and Personality," American Journal of Psychiatry, vol.116, no.10, 1960, p.938.
35. Howells, William, Mankind So Far, Doubleday, New York, 1944, p.138. Throughout this section, values given by different authorities vary, since measurements often involve certain imponderables such as skulls distorted out of shape by the ground.
36. Sinanthropus: ibid., p.144.
37. Solo Man: ibid., p.179.
38. Neanderthal Man: ibid., p.166.
39. Wadjak and Boskop Man: ibid., p.192.
40. Cromagnon Man: Ashley Montagu, Introduction to Physical Anthropology, Thomas, Springfield, Illinois, 1945, p.92.

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smaller one, though the learning process may take longer. (41) In a nutshell, his argument is that an absolutely larger brain (i.e., not larger relative to the body itself) will have a relatively as well as an absolutely larger number of cells in its cortex. A larger number of cortical cells makes more elaborate learning possible. The experiments upon which Huxley based this were conducted by the German biologist, Rensch. The data apply equally well not only to higher animals like birds, but even to beetles. By contrast, Zeuner reported that brain size becomes smaller with domestication, in spite of the fact that domestication almost certainly is accompanied by some enrichment of the environment, at least for the dogs which were the subject of his report. (42) He explained this as being the result of atrophy of some senses which become less important. Mention is made of an enriched environment here because Rozenweig found that in rats, at least, an enriched environment leads to cortical enlargement as well as increased convolution. (43) Leakey, as though to confuse the issue even further, reported the finding that some notable scientists have smaller cranial capacity than some notable pugilists. (44) Is it possible that the pugilist's brain enlarges in some area that has to do with his fighting capacity whereas the scientist's brain diminishes without duly compensating for the loss in some other area related to thinking?
     
Actually, it appears now that there is less certainty than previously even about the validity of "localization theories" i.e., the idea that certain parts of the brain are set aside for certain functions. Years ago, Ralph Gerard, in attempting to localize in the brain such functions as the faculty of speech, etc., wrote: "It remains sadly true that most of our present understanding of mind would remain as valid and useful if, for all we know, the cranium was stuffed with cotton wadding." (45)  This was written in 1946. Similarly, R. E. D. Clark noted that according to K. S. Lashley, no part of the upper brain is vital, but one part may take over the functions of another with relative ease. (46) The debate continues and even a symposium on localization of function in the cerebral cortex held in Oxford in 1954 came up with no altogether clear cut evidence of such area

41. Huxley, Sir Julian, Evolution in Action, Chatto & Windus, London, 1953, p.99.
42. Zeuner, F. E., "Domestication of Animals," in A History of Technology, vol.1, edited by Charles Singer, E. J. Holmyard and A> R. Hall, Oxford University Press, 1954, p.348.
43. Rosenzweig,Mark R., et al., "Brain Changes in Response to Experience," Scientific American, February 1972, p.22.
44. Leakey, L. S. B., a panel on "Man as an Organism," Evolution After Darwin, vol.3, edited by Sol Tax and Charles Callender, University of Chicago Press, 1960, p.168.
45. Gerard, Ralph, "The Biological Basis of Imagination," Scientific Monthly, June, l946, p.487.
46 Lashley, K. S.: quoted by R. E. D. Clark in Science and Religion, vol.1, no.5, 1948, p.223.

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specificity, except that language seems to be organized in the left hemisphere in those who are congenitally right-handed, and vice versa. Science News reported in 1966 that a man suffering from brain cancer had his entire left cerebral hemisphere removed and, contrary to all medical expectations, regained some ability to speak, write, comprehend speech, and move his right limbs. (47) The report said, "The brain may have a much greater capacity to reorganize itself than was believed." There are neural connections between areas of the brain and bodily functions, but if these areas are damaged or destroyed, other areas seem to take over. One of those who took part in the case (Dr. J. A. B. Bates) showed that even though such connections do seem to exist, precisely the same responses are obtained by stimulation of the white fibers of the cortico-spinal column as by stimulation of the gray matter itself. (48) It was felt that the position he took on this implied a radical break with the traditional doctrine of the hierarchical organization of function in the central nervous system.
    
A. Irving Hallowell, in a contribution to a Darwin Centennial Symposium, made this significant remark: (49)

     So far as integrative functions are concerned, the present weight of evidence appears to focus upon the influence exercised by the masses of nerve cells in the upper part of the brain stem upon the more recently evolved cortical areas. An older notion that the cortex itself was of prime significance because it was somehow "the seat of consciousness" no longer seems to make complete neurological sense.

     He then added this footnote: (50)

     Popular tradition, which seems to be largely shared by scientific men, has taken it for granted that the cortex is a sort of essential organ for the purposes of thinking and consciousness, and that final integration of neural mechanisms takes place in it.
     Perhaps this is only natural since there has been an extraordinary enlargement of the cortex in the human brain, and, at the same time, man seems to be endowed with intellectual functions of a new order.
     However, the whole anterior frontal area, on one or both sides, may be removed without loss of consciousness. During the amputation the individual may continue to talk unaware of the fact that he is being deprived of that area which most distinguishes his brain from that of the chimpanzee.

47 Science News, vol. 90, December 24, 1966, p.555.
48. Bates: referred to by 0. L. Zangwill, "Localization in the Cerebral Cortex," Nature, October 16, 1954, p.719.
49. Hallowell, A. Irving, "Self, Society and Culture in Phylogenetic Perspective," in Evolution After Darwin, edited by Sol Tax and Charles Callender, University of Chicago Press, 1960, vol.2, p.344.
50. Hallowell: quoted by W. Penfield and T. Rasmussen, The Cerabral Cortex of Man, Macmillan, New York, 1950, pp. 204-206, 226.

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     The most complete study in condensed form of which I am aware, of the relationship between brain size, both absolute and relative, and surface complexity was written by Weidenreich in a paper entitled "The Human Brain in the Light of Its Phylogenetic Development." It is difficult to summarize such a compact statement of the facts of the case, but we shall make an attempt. As a kind of introduction to his analysis of the data, Weidenreich observed: (51)

     Some time ago I came across a pamphlet published in 1934, which was written by an English physician. In the author's opinion, the only factors that determined man's evolution since his beginnings as a primitive primate are environment and natural selection.
     But his starting point is the premise, "Cranial capacity is a fairly accurate measure of the mental status from the most primitive primates to Homo sapiens."The self-confidence with which this statement is made is typical.

     Weidenreich then admitted candidly that we do not know of any fact which proves that mere increase in size of the brain is tantamount to an advance in mental ability. Indeed, increase of body size is normally accompanied by an increase in brain size, so that the elephant has a brain that weighs almost 5000 gm. and the brain of a whale may reach 10,000 gm. And yet for all that, in proportion to the weight of the body, the whale has a much smaller brain than man. This might seem to give man the edge, until it is discovered that the dwarf monkeys of South America, the marmosets, far surpass man in this respect, having 1 gram of brain per 27 gm. of body substance, whereas man has 1 gram of brain to 44 gm. of body substance. (52) And man is surpassed even more in these proportions by the capuchin monkey with one gram of brain substance for 17.5 gm. of body substance. It is as Weidenreich observed, (53) "Therefore, neither the absolute nor the relative size of the brain can be used to measure the degree of mental ability in animals or in man."
     
He then turned to the discussion of the surface pattern of the hemispheres and noted that primates and man do not differ from other mammalian orders with regard to the presence and abundance of the wrinkle system: (54)

     We are lost again if we suppose that the number or complexity of the

51. Weidenreich, Franz, "The Human Brain in the Light of Its Phylogenetic Development," Scientific Monthly, vol.67, August, 1948, p.103.
52. The fact is well known: see Adolph Schultz, "The Specializations of Man and His Place Among the Catarrhine Primates," in Cold Spring Harbor Symposia on Quantitative Biology, vol.15, 1951, p.45. Also Sir Solly Zuckerman, "Myths and Methods in Anatomy," Journal of the Royal College of Surgeons (Edinburgh), vol.11, no.2, 1966, p.92.
53. Weidenreich, Franz, "The human Brain in the Light of Its Phylogenetic Development", Scientific Monthly, vol.67, Aug., 1948, pp.104, 105.
54. Ibid., p.106.

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wrinkles is co-related with progress or perfection of mental faculties.
     The Capuchin monkey, which many experimental psychologists regard as equal in docility (i.e., educability) to any highly gifted chimpanzee, possesses an almost smooth brain surface, whereas the chimpanzee has a wrinkled one that comes close to that of man.
     The whale and its relatives, however, again steal the show. They have the greatest number and finest wrinkles all over the hemispheres, and the most intricate arrangement in the whole animal kingdom.

     He thus concluded that all the recorded facts indicate that neither the size nor the form of the brain, nor the surface of the hemispheres nor their wrinkled pattern in general or in detail, can possibly furnish a reliable clue to the amount and degree of general or special mental qualities. So there it is. Weidenreich said: (55)

     In the face of all these facts, it is hard to understand why people cannot get rid of the idea that mere size or configuration of a special convolution or fissure must give a clue to the mental qualities in general and to those of certain individuals in particular. . . .

     From the anatomical point of view, it must be rather obvious, therefore, that the uniqueness of man cannot be tied to the organ of brain, though there is no question that it is related to his capacity of mind, as K. A. Yonge observed: (56)

     It is in the ability to think about thinking that man regards himself as unique in the animal kingdom. It is not simply in his ability to think, that he can claim uniqueness, although he is vastly superior. Animals show their ability to associate one past experience with another and, as a result, to arrive at some plan of action. The rat learning his way through the maze, the chimpanzee figuring out a means to obtain the food out of arm's reach, the dog herding sheep. . . . This, for purposes of this Paper, is evidence of thinking. But man can think about thinking.

     Thus it is easy to confuse the brain of man with the brain of the animal, and say that in this respect man is merely a superior animal.
     
But it is not possible to compare the mind of man with the mind of the animal, for they appear to be in different categories. Konrad Lorenz wrote: (57)

     The central nervous system of animals is constructed differently from ours, and the physiological processes in it are also different from what happens in our brain. These qualitative differences are sufficient to make us conclude that whatever subjective phenomena may correspond to neural processes in animals must be considerably different from what we, ourselves, experience.

55. Ibid., p.106.
56. Yonge, K. A., "Of Birds, Bats and Bees: A Study of Schizophrenic Thought Disorders", Canadian Psychiatnc Association Journal, vol.3, no.1, 1958, p.1.
57. Lorenz, Konrad, On Aggression, Bantam Books, New York, 1967, p.202.

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     In summary, then, there is no precisely definable way in which man's brain can be considered anatomically superior to the brains of animals below him. Neither in its size nor in its surface complexity does its uniqueness seem to lie. That there is a qualitative difference, however, is almost universally agreed. But to define this qualitative difference is in a sense an impossible task. Where is the decisive point at which the uniqueness of any "different" thing becomes determinate? Who can really tell?
     
Most assuredly, man's mind is vastly different, no matter how similar his brain cells may be to animal brain cells. So, somewhere, some other factor has added a dimension which is missing in the animal world. We can see the effects of this dimension at once. And in a small way we can also discern some of the reasons why this added dimension was effective in man where it almost certainly could not have been effective in any other animal. A certain combination of anatomical features in the design of his body as a whole has allowed the special potential of his mind to express itself in unique ways These features, anatomical though they are, have effects far removed from any mere biological advantage. They have permitted not merely the creation of a superior technology -- for some animals build houses and construct dams, which are forms of technology of a sort but a whole series of cultural phenomena: language and art, social organization in which the individual may consciously sacrifice himself for the good of others, philosophy and science, ceremony and worship. . . . And above all, and most significantly of all, these features have provided an entirely appropriate channel for the revelation of God in Christ by incarnation in a truly human form.

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Copyright © 1988 Evelyn White. All rights reserved

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