Geschwind and Galaburda in their 1987 Cerebral Lateralization noted a number of patterns across studies that seemed to support a relationship between lateralization, handedness and a number of diseases and conditions. Follow-up studies often led to results that were ambiguous. Still, the work of Simon Baron-Cohen and his colleagues have come to conclusions that have suggested connections that Geschwind and Galaburda alluded to. Specifically, mother’s testosterone levels inform conditions characterized by male maturational delay. Marian Annett continues to pioneer an understanding of a paradigm characterized by random-handedness balanced by conventional handedness that she calls Right Shift Theory.

In other essays on this website (i.e., Evolutionary Theory, Neuropsychology and Autism), I have described the integral connection between heterochronic theory and the neuropsychological patterns observed by Geschwind and Galaburda, developed by Annett and Baron-Cohen. Heterochronic theory describes how species evolve when influenced by changes in the rate of timing of maturation and development. Neoteny is one of six heterochronic patterns, the prolongation or lifting of infant or embryonic features from ancient ancestors into the features of adult descendants, resulting in the slowing down of maturation, with features of early ontogeny appearing later in ontogeny over generations. One does not just mature slower. Features of the infant manifest in the adult. Acceleration is the reverse of neoteny, with the features of adult ancestors appearing in the infant or embryonic features of descendants.

Darwin discovered sexual selection. He did not intuit the close connection between sexual selection and social structure in human evolution though he observed a relationship between the two. It seems that Victorian prejudices prevented him from seriously considering that human evolution was heavily influenced by female sexual selection or matristic, female-centered societies. Ironically, Wallace shared few of Darwin’s prejudices that women and aboriginals were lower than white Western academics, yet Wallace rejected sexual selection. If Wallace had embraced the theory, perhaps he’d have had the insights that several of his contemporaries experienced, that female sexual selection may have been integral to human evolution. Wallace chose instead to believe that divine intervention was responsible for language, society and culture.

Among those Western intellectuals that considered that the human female may have been central to how we evolved were Marx and Engels. Anthropologist Chris Knight, in his Blood Relations, observes how this has resulted in the fracturing of Western theorizing of human evolution.

For 150 years these three disciplines, neuropsychology, evolutionary biology and anthropology, have evolved in separate directions, occasionally exchanging idea memes but mostly conducting their work in separate journals describing seemingly unrelated theories with different descriptive nomenclatures.

I’ve suggested that by observing the influence of social structure on the heterochronic patterns of neoteny and acceleration, various neurological, physiological, psychological and hormonal patterns emerge in descendants over time. Anthropology, evolutionary biology and neuropsychology are three names for whether the patterns are observed in a society at a particular time, in society over time or in an individual within that society. These three disciplines are parsing out the scale and timing of experience. Engineering has one language to describe the almost 100-year evolution of the auto, general auto design and the products of specific auto manufacturers. It would be useful if we had a single language for human beings.

A potentially useful language is the language that lovers speak, the evocations of testosterone and estrogen. A mother’s testosterone levels at six weeks before birth decide the testosterone levels and maturation rates of her children. A high-testosterone mother births high-testosterone daughters and low-testosterone sons. A low-testosterone mother gives birth to low-testosterone daughters and high-testosterone sons. The environment influences those testosterone levels, adjusting the testosterone levels in her children. If the mother mates with a male from a genetic line long separated from hers (i.e., an American Indian mating with a Jew), the progeny may display hormonal constellations or maturational trajectories that are ancient. If a very high-testosterone woman is attracted to a very low-testosterone man, the children’s maturation may be vulnerable to environmental influences exaggerating the mother’s testosterone levels even further.

The mother’s womb is the place where the scale and timing of experience converge. A society’s social structure is informed by the testosterone levels and maturation speed that her children emerge with. High-testosterone (T) females mating with low-testosterone (t) males form matrifocal, matristic or partnership societies. Low t females pairing with high T males create patrifocal, patristic or male domination societies.

Social structure changes over time. Evolution reflects those changes. These changes manifest in specific features of individuals within those societies, including dispositions for particular diseases, conditions and disorders informed by their particular hormonal tendencies driven by social structure.

Estrogen has been studied far less than testosterone. Not unlike observing a baseball game by watching only what occurs at first base and right field, understanding the impact of estrogen in this dynamic, intuiting the rules of the game but being only able to observe part of the game, is a challenge. Nevertheless, like Geschwind and Galaburda in 1987, I’d like to make some tentative hypotheses and see if some of the patterns that they observed twenty years ago make more sense from this new point of view. I’d like to see how many of the rules of baseball we can infer by watching a fraction of the game.

Let’s imagine that not only testosterone levels are set at a particular time in the woman’s womb. Let’s estimate that estrogen levels in the mother decide the estrogen levels in her children, operating with a similar dynamic. This is a big leap, but the implications in social structure (anthropology) and evolution (evolutionary biology) are perhaps useful.

Imagine that a mother with high estrogen (E) gives birth to a low (e) estrogen son and a high E daughter. A low e mother gives birth to a low e daughter and a high E son. Estrogen confers caring and caregiving, along with a tendency to make aesthetic evaluations or judgments, as in sexual selection. Estrogen compels caring and a biological aesthetic.

Consider that just as testosterone propels maturational trajectories, resulting in changes in evolution, societies and the features of individuals, changes in estrogen result in similar profound modifications in evolution, society and individual characteristics. These changes are more difficult to see when everyone’s eyes in a patrifocal society are on the ball clearing a fence in left field. Still, there are 18 players in the game. It’s not all about the batter and the pitcher.

Perhaps it was the catcher that told the pitcher to throw a fast ball.

It may not be obvious that estrogen is calling signals in biological and societal evolution, but the possibility might make many patterns clear.

Consider the following…..

F te/M TE Conventional Patrifocal
F tE/M Te Warrior Patrifocal
F Te/M tE Contemporary Matrifocal
F TE/M te Classic Matrifocal

F te/M TE means low-testosterone & estrogen females, high-testosterone & estrogen male.

F tE/M Te means low-testosterone, high-estrogen female, high-testosterone, low-estrogen male.

F Te/M tE means high-testosterone, low-estrogen female, low-testosterone, high-estrogen male.

F TE/M te means high-testosterone & estrogen female, low-testosterone & estrogen male.

These are the outliers. The work of Marian Annett and her Right Shift Theory suggest that perhaps most people are in middle zones, not exhibiting particularly high or low levels of either hormone. Still, we are hypothesizing that societies will tend to lean powerfully in a matrifocal or patrifocal direction, evidencing populations with tendencies to fall into one or two of the four quadrants. All societies will exhibit examples of all four quadrants. I am hypothesizing that one or two of the four will be emphasized.

Because the mother’s testosterone levels always propel the two sexes in opposite directions (maturational delayed vs. maturational accelerated), we are hypothesizing that mother’s estrogen levels fashion her children’s exhibition of estrogen in opposite directions.

Domineering, caring, discriminating men choose cooperative women (F te/M TE).

Domineering men choose cooperative, caring, discriminating women (F tE/M Te).

Commanding women choose creative, cooperative, caring, discriminating men (F Te/M tE).

Commanding, caring, discriminating women choose creative, cooperative, aloof men (F TE/M te).

Marian Annett’s hypothesis of a balanced polymorphism or a society evidencing a seamless gradation between two outlier or extreme populations seems a reasonable way to view the patterns we are hypothesizing here. We would hypothesize that different societies will evidence varying balanced polymorphisms depending on their social structure proclivities. Specific hormonal constellations will become reinforced by womb conditions.

Deep changes in a society can occur quickly when there is a change in hormonal constellations. There can be sudden shifts from matrifocal to patrifocal or patrifocal to matrifocal. For example, if a matrifocal society is highly stressed over time by patrifocal incursions, the ideal male mate may shift from one displaying cooperative tendencies to a male quick to fight. Formerly highly valued aesthetic-oriented males may find themselves outside the pool of highly valued potential partners. In mere generations, physiological, hormonal and neuropsychological transformations may occur.

Nomadic populations exposed to changes in light (light influencing the pineal gland, which moderates testosterone levels) may experience radical fluctuations in a society’s social structure, impacting evolution over time.

Radical changes in diet manifesting in large amounts of high quality fats and nutrients might raise a female’s estrogen and testosterone levels, compelling a shift in social structure in the direction of female choice, with females choosing cooperators over warriors.

Hypothesizing both estrogen and testosterone as players in the transformation of species, societies and individuals, we might be able to infer rules in the game of life too subtle when we choose to only notice the behaviors of males. Details describing the power of women go unremarked when viewed from the elevated position of disciplines that do not play ball with one another. Consider that when we are able to see the whole playing field and are able to view all players, we notice that half of them are females and that the catcher, with mask withdrawn, is a woman.

It takes at least two to play a game. It’s time we recognize that the females are always players.

(Thanks to Riane Eisler’s The Real Wealth of Nations for inspiring the conclusions that I came to in this piece.)


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