22 R. Galambos, T. T. Norton, and G. P. Fromer, "Optic tract lesions sparing pattern vision in cats," Experimental Neurology, 1967, 18: 18-25.
23 I am paraphrasing the superb recent review of this problem by Burton Rosner,
"Brain functions," Annual Review of Psychology, 1970, 21: 555-594.
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organism of far greater adaptability to the constantly changing environmental challenges. I am thinking here of such challenges as characterize the successive glaciations of primate man's existence, and, of course, that even greater challenge of the breakdown of the bicameral mind to which man adapted with consciousness.
But this does not mean just that adult man's behavior is less rigid than his forebear's, though this is of course true. More important, it provides an organism where the early developmental history of the individual can make a great difference in how the brain is organized. Some years ago, an idea such as this would have seemed very far-fetched indeed. But the increasing tide of research has eroded any rigid concept of the brain, and has emphasized the remarkable degree to which the brain can compensate for any structures missing either by injury or by congenital malformation. Many studies show that brain injury to animals in infancy may make little difference in adult behavior, while similar injury to adults may have profound changes. We have already noted that early injury to the left hemisphere usually results in the switch of the entire speech mechanism to the right hemisphere.
One of the most astonishing of the cases that demonstrate this resiliency of the brain is that of a thirty-five-year-old man who died of an abdominal malignancy. At autopsy, it was revealed that he had a congenital absence of the hippocampal fimbria, the fornix, septum pellucidum, and the mass intermedia thalami, with an abnormally small hippocampus and abnormally small hippocampal and dentate gyri. In spite of these remarkable abnormalities, the patient had always displayed an "easygoing" personality and had even led his class in school!24
Thus, the growing nervous system compensates for genetic or environmental damage by following other but less preferred de-24 P. W. Nathan and M. C. Smith, "Normal mentality associated with a malde-veloped Rhinencephalon," Journal of Neurology, Neurosurgery and Psychiatry, 1950, 13: 191—197, as cited in Rosner.
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velopmental paths which utilize intact tissue. In adults, with development completed, this is no longer possible. The normally preferred modes of neural organization have already been achieved. It is only in early development that such reorganization of the systems of multiple control can take place. And this is definitely true of the relationship between the hemispheres so central to this discussion.25
With this as a background, I do not see the difficulty in considering that, in the bicameral epochs, what corresponds to Wernicke's area on the right nondominant hemisphere had its strict bicameral function, whereas after a thousand years of psychological reorganization in which such bicamerality was discouraged when it appeared in early development, such areas function in a different way. And similarly, it would be wrong to think that whatever the neurology of consciousness now may be, it is set for all time. The cases we have discussed indicate otherwise, that the function of brain tissue is not inevitable, and that perhaps different organizations, given different developmental programs, may be possible.
25 R. E. Saul and R. W. Sperry, "Absence of commissurotomy symptoms with agenesis of the corpus callosum," Neurology, 1968, 18: 307; D. L. Reeves and C. B. Carville, "Complete agenesis of corpus callosum: report of four cases," Bulletin of Los Angeles Neurological Society, 1938, 3 : 169—181.
C H A P T E R 6
T h e Origin of Civilization
BUT WHEREFORE should there be such a thing as the bicameral mind? And why are there gods? What can be the origin of things divine? And if the organization of the brain in bicameral times was as I have suggested in the previous chapter, what could the selective pressures in human evolution have been to bring about so mighty a result?
The speculative thesis which I shall try to explain in this chapter — and it is very speculative — is simply an obvious corollary from what has gone before. The bicameral mind is a form of social control and it is that form of social control which allowed mankind to move from small hunter-gatherer groups to large agricultural communities. The bicameral mind with its controlling gods was evolved as a final stage of the evolution of language. And in this development lies the origin of civilization.
Let us begin by looking at what we mean by social control.
T H E E V O L U T I O N O F G R O U P S
Mammals in general show a wide variety of social groupings, all the way from the solitariness of certain predatory animals to the very close social cohesiveness of others. The latter animals are the more preyed upon, and a social group is itself a genetic adaptation for protection against predators. The structure of
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herds in ungulates is relatively simple, utilizing precise genetically given anatomical and behavioral signals that are all evolved for group protection. Primates have a similar vulnerability, and for the same reason are evolved to live in close association with others. In dense protective forests, the social group may be as small as six, as in gibbons, while on the more exposed terrains, the group may be up to eighty, as in the Cape baboons.1 In exceptional ecosystems, the group size may be even larger.
It is the group then that evolves. When dominant individuals give a warning cry or run, others of the group flee without looking for the source of danger. It is thus the experience of one individual and his dominance that is an advantage to the whole group. Individuals do not generally respond even to basic physiological needs except within the whole pattern of the group's activity. A thirsty baboon, for example, does not leave the group and go seeking water; it is the whole group that moves or none.
Thirst is satisfied only within the patterned activity of the group.
And so it is with other needs and situations.
The important thing for us here is that this social structure depends upon the communication between the individuals. Primates have therefore evolved a tremendous variety of complex signals: tactile communication ranging from mounting and grooming to various kinds of embracing, nuzzling, and fingering; sounds ranging from assorted grunts, barks, screeching, and yak-king, all grading into each other; nonvocal signals such as grinding teeth or beating branches;2 visual signals in a variety of facial expressions, the threatening, direct eye-to-eye gaze, eyelid fluttering in baboons in which the brows are raised and the lids are lowered to expose their pale color against the darker background 1 Irven DeVore and K, R. L. Hall, "Baboon Ecology, " Ch. 2 in Primate Behavior, I. DeVore, ed. (New Y o r k : Holt, Rinehart and Winston, 1965), pp. 20—52.
2 K. R. L. Hall , " T h e sexual, agonistic, and derived social behaviour patterns of the wild chacma baboon, Pafio ursinus" Proceedings of the Zoological Society, London, 1962, 139: 283—327.
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of the face, together with a yawn that bares the teeth aggressively; various postural signals such as lunging, head jerking, feinting with the hands, and all these in various constellations.3