Human evolution theory utilizing concepts of neoteny & female sexual selection
An etiology of neuropsychological disorders such as autism and dyslexia, and the origin of left handedness.
Spoken language could not suddenly appear without the facilities to communicate symbolically already established in human neurology . Today, if human children are not taught language by puberty, language can not be learned. If early humans did not muddle through language/communication as adults, who taught the children? Yet evidence of culture, often assumed to be evidence of language, did not appear slowly, but suddenly. There is no paradox to be found here if the facilities for symbol and metaphor were already present in another physical, gestural, touch form (Hewes, 1973a) and transferred over to spoken language. Bates et. al. (1979) has suggested that heterochrony may have created the conditions responsible for spoken language.
Humans today, if right handed, are usually lateralized for language use in the left hemisphere. Lefthanded, ambidextrous, and often righthanded people from families with many lefthanded members are described by Norman Geschwind (1985) as anomalously dominant or non-lateralized for language because of the variety of ways that language is processed differently from the "standard" righthanded person.
When speech bridged over from non-verbal communication, some practitioners were better at the skill than others. Judging from the correlations of dyslexia and stuttering with non-laterally committed people (Bradshaw and Nettleton, 1983), the anomalously dominant, we are calculating that men a little more disposed to use of a single hemisphere had an easier time picking up the skill of spoken language. It has been estimated that the central location of the tongue and larynx puts at a disadvantage persons requiring both hemispheres for coordination of these mid-line organs (Maclean, 1990). As women had picked men as procreative partners based on their talent at the song and dance, we estimate women now picked men for their talent at this new marvel, speech, because of its ability to evoke feelings-of-something-larger-than-the-self. We hypothesize that women must have picked men for this skill because today, men are more laterally committed than women (Witelson, 1989). Males are predominantly committed to a single hemisphere because speech, once it showed evidence of its utility, became a highly selected for trait. After song had primed the speaking apparatus to be ready for the spoken word, spoken language itself was more successfully executed by males with a tendency to use a single hemisphere for language.
The sexual selection process continued to be characterized by the choosing of variations on a theme, novelties, slight differences that evoke feelings of attraction. The feelings evoked by a desire to bond with something-larger-than-the-self became assigned to abstractions, the concepts evoked by words. As a female bird chose the mate with the brighter color red, the early hominid female chose the dancer with grace-filled backstep hitch. Women around 40,000 years ago started picking their mates by the power of their poetry, the beauty of their words. This group of people, genetic elders, one might say, are still with us today.
A hidden minority of people manifests itself in every culture of the world today occupying a fairly consistent percentage of the local population, around 18.5% to 35% (Geschwind & Galaburda, 1987) based on some lateralization studies. This population is composed of the anomalously dominant, who we know most familiarly as the lefthanded or ambidextrous person. These individuals and their families are not strongly predicated toward use of the left hemisphere for language, and they share the same strengths (creativity, associational or holistic thinking, musical composition, visuospatial abilities) and weaknesses (dyslexia, autism and stuttering (Gotestam, 1992)). Shift theory suggests that these are the genetic remnants of pre-language culture; the musical composers, musicians (Hastler, 1991b), artists (Hastler, 1991a, 1992), architects, dancers, and people in the creative arts. There is data that suggests that a high percentage of homosexuals come from this genetic pool (McCormick, 1990; Witelson, 1991a). Some manic-depressives (Crow, 1995b), many schizophrenics (Crow, 1997), a specific class of alcoholics (London, 1986; McNamara, 1994), and people inclined toward promiscuous sex often fit into this group. Many obese females share these characteristics. According to shift theory, these peoples preceded the appearance of the strongly lateralized right handed individuals that we are most familiar with today. A number of cultures evidence features associated with our pre-speech-more-neotenous genetic type such as the Eskimos or Inuit, the Polynesian, several African cultures and possibly continental pre-Indo-European cultures like the Irish and the Basque.
The influence of split-consciousness, what we usually call the conscious mind, suddenly appeared insinuating itself into the fabric of the community, a community centered around the women. This new way of thinking, characterized by an increased dissociation from its feeling base, was practiced by males, males picked by women for their facility at speech and for a brand new ability, the ability to plan. Time had been invented. These new males identified less and less with the characteristics of what we now call the unconscious. They were learning to identify with words. Perhaps, if their words were less committed to a single hemisphere, like those of their women, they would not have ended up drifting so far from the sensual reality that the words themselves represented. But the words, these new symbols, were mostly processed in one hemisphere, the left hemisphere, associated with rhythm, the element of song and sound most similar to the spoken symbol. The most effective utilizers of these symbols, the ones best at attaining specific goals, were the males who could line the words up making the words create a future and a past, a here and a somewhere else. They could rip the world into little pieces and by naming and isolating things and the separate actions that those things did. The left hemisphere is better at rhythm, simultaneity, temporal order, duration and timing (Bradshaw and Nettleton, 1983). Having mapped their experience through these modalities and the sense of sound, time was funneled into a narrative frame of reference. Language was not in the body anymore. One did not dance it, gesture it, feel it. Language was now something very strange. It was abstract. And it controlled time.
It is important to note that the practitioners of the new art of spoken language had smaller corpus callosums, the tissue bridge between the two hemispheres, than either women or anomalously dominant males. This is consistent with corpus callosum studies of contempory humans ( Witelson, 1985, 1991a; Moffat, 1997). This smaller physical structure when coupled with the effects engendered by the identification with language decreased the communication between hemispheres, creating a lag in the time it takes to get messages from one side to the other, further isolating the hemispheres from one another. The additional hemispheric differentiation increased the time dissociation skills creating an even better ability to plan, to isolate goals. If smaller corpus callosums increased dissociation skills, sexual selection would have further selected for males with smaller corpus callosums.
What had begun with the female in non-human species picking mates based on slight differences in an established norm, evolved to the human female picking her mate based on slight symbolic differences in a spoken norm.There was still the dancing and singing, but ritual was becoming subsumed by myth. Myth and ritual were not identical anymore as they had to have been when message and medium were the same. Myth could be separate. There could be legends now. There could be folk tales. There could be lies.
At first the effects of language were subtle, but with time its effects became more invasive as split-consciousness began the breakdown of the sexual selection/neoteny feedback loop. The appearance of the "conscious" mind, split-consciousness, made for greater difficulty in identifying with that-which-is-larger-than-the-self. In a sense, females helped create an environment capable of spawning patriarchal culture by selecting highly lateralized men for their skill in spoken symbolic language.The portion of the selection process emphasizing agility, endurance, and sound was beginning to recede. Neurologically, it could be suggested that because rhythm is a left hemispheric operation, sharing space with language processing, the growth in language skills took away from the ability to excel in the dance and song by gumming up the rhythm with the words.
In the evolving culture of spoken language females are not now the sole arbiters of time as they had been with their menstrual cycles connecting the tribe with the cycles of the sky (Knight, 1991). With language, even though right handed men are not as skilled with associational language as women, men can now control time. In fact, right handed males are far better at skills involving organization within time than either anomalously dominant males or females.
At the point when humans began to pour out of Africa to populate the world, the breakdown was fully under way. The similarity in myths from around the planet suggests that the loss of non-spoken language occurred before those peoples diffused. The fact that a fairly consistent percentage of most populations are left handed suggests this too. The ability to diffuse so quickly to so many different, formerly unfamiliar, habitats indicates facility with spoken symbol had already been established.
The human female determines in culture, just as in females often do in biology, the direction of evolution. Sociobiology suggests that the forces of biological evolution are identical to the forces of cultural change. Shift theory agrees, but places the leverage of these changes in the body of the female arbitrated by her choice in mates and the changes in her body during pregnancy. Sexual selection, heterochrony (including neoteny and acceleration), and zygote and uterine selection join the sociobiological focus on natural selection as the forces that guide cultural change.
Another way to understand the transition to language facility from pure song and dance, to patrifocal from matrifocal societal structures, is by examining the hormonal constellations reinforced by the choices females were making in their mates and the relationship between relative levels of testosterone with specific cerebral lateralization constellations.
Between 100,000 and 40,000 years ago, females began picking males (Crow, 1995a) with the feature of being able to organize words linearly in time, to communicate not only in symbol, but in sign. (Symbol makes connections through association; sign forms connections through representation. Sign is more removed than symbol from sensual experience affording greater powers of concept manipulation.) We hypothesize that males with this characteristic had, and have, higher T. Males with this characteristic would retain enhanced abilities to hunt and organize events sequentially. In other words, females began picking males for characteristics that evidenced the opposite hormonal constellation than they had been for the previous 2 million years. Social structure shifted from matrifocal to patrifocal, from promiscuous social structures to polygynous and monogamous constellations. With the advent of patriarchal culture, starting at the earliest 40,000 years ago, a radical change occurred in the evolutionary trajectories of human beings. There was a shift in the sexual selection process. Increasingly higher T males began choosing their procreative partners choosing females for their docility, cooperativeness (Crook, 1972) and a predilection to live within polygynous or monogamous social structures.
Higher T males, at this point in our evolution, evidenced increasingly asymmetrical brain lateralization. Geschwind and Galaburda (1987) hypothesize that testosterone is the primary agent responsible for variations in cerebral lateralization. The timing of the relative levels of T is vitally important to understanding variations in language facility. The absence of light has an effect on the pineal gland which results in a diminution of T production (Geschwind & Galaburda, 1987). Most people in temperate zones have lowered T in winter and raised T in summer. It is hypothesized that this pattern was established in equatorial regions according to the diurnal cycle (Geschwind & Galaburda, 1987). Changes in migration patterns away from equatorial regions, perhaps to southern Africa or into the Eurasian continent, could have placed humans at a latitude where symmetrical brains became more lateralized as a result of the changes in light and its influence on the pineal gland which regulates testosterone. Seasonal fluctuations in light hypothetically also caused asymmetrical cerebral lateralization at conception and during gestation (zygote & uterine selection) if male T is high at the point of sperm production or if female T is low during the phase of gestation when developmental rates for the fetus are set. The evolution of language from symbol to sign was occurring during the same period. The increased lateralization made further dissociation more likely which made possible the transition into sign, and the split consciousness we identify as "thought". Other potential triggers to increased lateralization could have included dietary changes or ceremonial natural inebriants.
For the first two million years of hominid evolution males and females had developed an increasingly androgenous (Hassler, 1992), promiscuous dance and song driven culture (Knight, 1991). When a fully linear language appeared, female and male evolutionary trajectories diverged. There was a further shift to an aggressive male, high T frame of reference enforced by patriarchal societal criteria in sexual selection. In this emerging polygynous culture males chose females for their low T docility and for those characteristics evidencing high fertility. Females that looked and acted young were more likely to be chosen to have progeny. Males now choose females for their neotenic features (Jones, 1995).
It is in a patriarchal context that much of the sociobiological (Chagnon & Irons, 1979; Buss, 1989) and evolutionary psychological (Barkow et. al., 1992) criteria for natural and sexual selection in humans makes sense. Patriarchal society could control the kind of male that would have the opportunity to procreate. Female infanticide is patriarchal culture's method for keeping only high T males in the procreation pool. In polygynous society engaging in female infanticide there are far fewer females than males to mate. Many males go mateless, specifically the males considered least desirable as husbands by the fathers of the females to be married.
Shift theory suggests that female infanticide, the culturally encouraged killing of female infants, is one of the manifestations of sexual selection in a cultural context. Female infanticide can now be understood as a form of cultural preservation. By decreasing the number of women to less than the number of available men, the more specific the features that can be chosen for in the character and genes of the males by the females; the more culturally rigid, both in terms of cultural ideas and the genetic pool, the culture will continue to be. A culture keeps tight control of its degree of diffusion or drift by maintaining a relatively small female/male ratio. This results in a dramatic shift toward a selection of highly specific traits when the culture calculates that new traits are needed. As culture started to idealize war, the families of those women or their fathers chose a mate based on success-in-war criteria. Female infanticide decreased the number of men likely to create progeny increasing the likelihood that the warlike criteria would be passed on to the next generation.
In a culture where male aggressive behavior is highly valued, as in the Yanomamo of South America, female infanticide can be understood as the process that the culture uses to select only those males displaying maximal aggression in social relations. Mothers often kill their female infants. Female/male ratios approach 100:140 at puberty in many tribes (Hawkes, 1981). Male heads of household control who young females will mate with. All females are mated (Chagnon, 1979). Aggression becomes highly reinforced as a male trait when males not succeeding at fulfilling the highly valued cultural criteria of displays of aggression, or not a member of a family with high status as a result of successful use of aggression, do not become mated. Females are at the center of this process of cultural stability and change, in three ways: female infanticide, mate selection (males taking control of this aspect in most cultures), and whether females choose to commit adultery. Only one in ten births in the Yanomamo are a result of extramarital involvements (Chagnon, 1979), a very low number. (By comparison, in England this century, a 20% ratio of extramarital births has been discovered in working class and middle class neighborhoods.)
Whether a culture is in flux or is stable, female infanticide becomes the tool by which a patrifocal culture controls its diffusion and concentrates its target ideas and genes. Female infanticide would tend to decrease at a point in a culture's development when that culture is characterized by respect or tolerance for an independence of ideas. The looser the cultural ideals, the less compelled a women will feel to mate with a specific kind of man and the less important female infanticide becomes as a tool for stability or targeted change.
Female infanticide as a function of sexual selection introduces an additional tool in shift theory to describe the process of cultural creation and preservation since the African diaspora. Imagine a culture whose boundaries broke down, where infanticide ended, the selection for specific traits within a culture ceased and women had the power to pick procreation partners using whatever criteria they chose. You would end up with a world not unlike the one we, in the West, live in. The huge increases in technology and many of the other innovative trappings of contemporary culture are profoundly influenced by the fact that women are choosing mates outside the criteria of any specific culture. No way is being preserved. All ways are open. For the first time culture is undefined and open ended. It is no coincidence that in the United States so much that is new has been and is being created. It is the first place in the world characterized by a complete breakdown of a specific cultural criteria for the ideal man. Women in contemporary western culture are choosing mates based on a new criteria, their own idiosyncratic ideas based on the hodge podge of cultures that comprise their background combined with the American ideal of independence. This new criteria is now becoming the cultural criteria, as women and culture together, form a new understanding of what they want in a mate; what it is that they feel will make it most possible for them to feel loved and for the culture to survive.
Love can now be defined as part of the constellation of feelings connected to feeling-part-of-something-larger-than-the-self. Women have the opportunity to choose their mates based on their mate's ability to evoke love with its more difficult-to-put-into-words epiphanic aspects. It is our estimation that men alone can't create an opportunity for a woman to feel a part of something-larger-than-the-self. It is vital that the woman and the man be an integral part of a larger community where the epiphanic aspects of love can be shared. A return to community is essential to an individual's experience of security and peace.
The principle behind female infanticide, sexual selection, is in evidence today. Western women by: marrying later, following career instead of family if that gives them satisfaction, using contraception and abortion, leaving marriages where they feel unloved before progeny are produced, having children only with men by whom they feel loved; make the selection process more and more tight without having to decrease the relative number of females to males. Advertising extols the visual virtues of the extremely skinny woman, women with such low fat levels that menstruation is compromised, further reducing the number of procreating females. The net result is that the world we are moving into is becoming characterized by far less ferment as the women's cultural criteria for a good man becomes more secure. There will be far more joy. As we pass out of this 5000 year old Indo-european tradition of extreme polarization, women can now again choose a mate based on his ability to evoke feelings of feeling-part-of-something-larger-than-the-self.
The net result of these shifts are that the hormonal trajectories over the last 40,000 to 100,000 years will reflect an increasing developmental delay in females characterized by decreasing T. At the same time males show evidence of developmental acceleration with increasing T. It is from this theoretical foundation that we make predictions concerning the structure of health and disease in contemporary society.