Marian Annett (Annett & Manning, 1990; Annett & Kilshaw, 1984) has hypothesized a balanced polymorphism in dyslexia that neatly fits with my theory of biological and societal evolution I am calling a Theory of Waves, formerly Shift Theory.  The Theory of Waves predicts a specific structure of health and disease in humans.  Nineteenth Century heterochronic theory’s descriptions of the operation of relative rate and timing changes of development and maturation are directly transposable to Annett’s (1985) right-shift theory.  It fact, superimposing Gould’s (1977) clock model of heterochronic evolution directly over Annett’s (1985) right-shift graph reveals the relationship among human evolution, the etiology of cerebral asymmetry and neurological disorders such as autism.

Right-shift theory (Annett, 1985) states that there is a gene (+) that predisposes most people for language facility.  Annett noted that there is a difference in the distribution of handedness between human and animal populations characterized by a right-shift in human beings.  This right-shift makes clear that not all humans are equally well disposed to language use.  People with a (- -) genotype (18-19 % of the population) evidence no predilection to specific handedness or cerebral asymmetry and so achieve a left- or right-handedness close to random.  People with (+ +) (32%), or a strong predilection to right handedness and asymmetrical lateralization, are highly disposed to language usage, but at the expense of right-hemispheric strengths.  Annett believes the mixture of both genetic propensities, (- +) offers the advantages evidenced by 49% of the population belonging in this category.  She characterizes these advantages as a balanced polymorphism (Annett 1984, 1990) when applied to overall strength in language facility.  It is important to understand that changes from population to population are gradual, not clearly demarcated, and that movements across this arc or spectrum from (- -) to (+ +) are incremental.

Heterochronic principles describe the effects of relative rates of development and maturation on species evolution.  I believe these concepts can be used to describe specific developmental trajectories in individuals vulnerable to neurological conditions.  Geschwind and Galaburda’s (1987) observations form the foundation for the patterns I have discerned.  They noted the connections between handedness; immune and autoimmune disorders and conditions associated with maturational delay.  The following patterns have been particularly noteworthy.

1) High testosterone (T) females (the older genotype) are at the (- -) end of the developmental spectrum and are developmentally accelerated compared to the low T females (+ +) at the developmentally delayed end of the spectrum.  Females at the right end are markedly more neotenous than left end females.  At the left end, relative to the females at the right end, the females are more left-handed and ambidextrous, featuring maturational acceleration.

2) Low T males (the older genotype) are at the (- -) end of the developmental spectrum and are maturational delayed compared to the high T males at the (+ +) other end.  Males, perhaps, exhibit more variation than females (Darwin, 1871) in the arc from (- -) to (+ +).  At the left end, relative to the males at the right end, the males have bigger brains (Annett, 1991), more symmetrical cerebral hemispheres, larger corpus callosums (Witelson, 1991a, 1991b, 1989, 1985), lower T (Tan, 1990), slower metabolic rates (Badcock, 1991), a less acute sense of the passing of time, increased left-handedness and ambidextrousness and increased speed (Annett, 1984), agility and coordination.  Males at the left end are markedly more neotenous (Coren, 1991) than males at the right end.

3) Females with high T give birth to females with high T and males with low T.  Males with low T tend to sire progeny characterized by females with high T and males with low T.  Older females, females with higher T, have more left-handed progeny, not because of increased birth trauma, but because females program the developmental rate of their progeny based on the sex of their progeny and the mother’s T level (Geschwind & Galaburda, 1987).  Low T females and high T males create low T females and high T males.

4) The eight environmental variables influencing T; light (Geschwind & Galaburda, 1987), diet (Schmidt , 1997), body fat (Ross, 1986; Glass, 1977), alcohol and drugs (Castilla-Garcia, 1987; Ahluwalia, 1992), tobacco (estrogen levels) (MacMahon, 1982; Barrett-Connor, 1987), touch, physical activity (MacConnie, 1986; Morville, 1979) and stress (James, 1986) often do not affect the two sexes the same way.  For example, increased body fat raises female T and lowers male T (Pasquali, 1991).

5) These eight specific environmental variables impact the distance and direction progeny can slide along the (- -) to (+ +) developmental arc.  Moving left and right across the arc moves people backwards and forward in genetic time.  Impact points include the somatic environment of the parents at zygote creation and the uterine environment.  Along with sexual selection, uterine environment (Geschwind & Galaburda, 1987) has the greatest influence on evolution in humans.  Particularly vulnerable to neurological disease are those children whose parents are genetically already at either the left (- -) or right (+ +) ends who are exposed to these environmental variables.  It is by the increasing or decreasing of the parents’ testosterone (and possibly estrogen) levels that these variables further impact the developmental maturation rates of these vulnerable genotypes.  For example, the raising and lowering of the mother’s T levels directly influences the developmental rates of the children during gestation (Geschwind & Galaburda, 1987).

6) Left spectrum individuals retain the older genotype, evidencing skill clusters highly valued before the advent of the (+) gene for a decrease in corpus callosum size and a reduction in portions of the right cerebral hemisphere, which increased cerebral asymmetry.  The highly selected (sexual selection being the primary selection force) character of the (+) gene proffers a heightened sense of passing of time (Marshack, 1972), increased split consciousness (Thompson, 1981), with a resulting ability to use language linearly, to plan (Annett, 1985).  The (+) does not increase language facility directly; it creates an increased time dissociation evolving symbol to sign through a disassociation of the cerebral hemispheres.

7) Dyslexia is not the only condition that has confounded studies by masking its roots at both the left and right ends of the developmental spectrum (Annett et al., 1996).  I suggest that schizophrenia, Tourette’s, diabetes and several other diseases and conditions may be split according to the same principles.  By using peg tests (Annett, 1985); comparisons of brain size, planum temporale (Annett, 1992) and corpus callosum (Witelson, 1985); T levels; metabolic rates; developmental stage markers; and family histories, we can sort out the (- -) from the (+ +) from the pathological cases.  Pathologically, developmental delayed and accelerated individuals can now be identified and treated separately from the genetic/environmental cases.  The postnatal influences of the eight environmental variables mentioned above can then be assessed, because in addition to influencing a child’s developmental rates before birth, these same variables can exacerbate and alleviate existent conditions and diseases by their ability to raise and lower T.  Raised testosterone can have profoundly negative effects on the immune and autoimmune systems (Wingfield et al., 1997).  By assessing where a person naturally belongs on the left-right scale, a person’s natural T level can be calculated.  Once a person’s natural T level is known, the same eight variables can be used to change T, bringing that person in line with his or her natural immune and autoimmune threshold.  It is vital to note that the influence of these eight variables masks the natural T levels existent in each individual, throwing off studies and confusing the patterns.

8) The timing of the onset of puberty, the heterochronic principle of progenesis (Gould, 1977), has powerful correlations with neurological and cognitive variation.  Diet, percentage of body fat and physical activity are primary variables responsible for pubertal timing.  There are studies (Saugstad, 1989) that suggest that specific forms of schizophrenia and bi-polar disorder are directly related to the timing of the onset of puberty.  The relationship between pubertal timing and an individual’s location on the developmental arc may reveal in greater detail the etiology of specific diseases.  Depression may be directly related to the worldwide curtailment of the final stage of cognitive development, abstract thinking, caused by an earlier onset of puberty.  There has been a drop in the age of puberty by three to four years over the last 100 years in urban cultures worldwide (Eveleth & Tanner, 1976) caused primarily by changes in diet.  These dietary changes signal our bodies that increased fat, carbohydrate, and protein resources are available for an increase in birth rate, accomplished by lowering the age of procreation; a naturally selected response.

9) Tracking the distribution of neurological conditions at the left end along the (- -) to (+ +) spectrum is tracking the sequence of our genetic heritage and cultural history.  At the far left end is autism, representing anatomically modern humans maybe 100 M years ago when we had bigger brains (Wiercinski, 1979; Lainhart, 1997), ambidextrousness (Soper, 1986) and no dominant hemisphere.  I hypothesize that the absence of constant touch as infants (Witelson, 1991a), and the absence of constant auditory rhythm and music pattern in a genotype as old as autism that requires constant touch and rhythm for full functioning, is responsible for many autistic syndrome complications over and above expected developmental delays.  Phonetic dyslexics (Annett, 1990); stutterers (Corballis, 1981; Bryden, 1994); many Tourette’s sufferers (Shapiro et al., 1972); many homosexuals and lesbians (McCormick et  al., 1990); many gifted athletes, mathematicians, artists, musicians (Deutsch, 1978; Hassler, 1991b; Hasler & Gupta, 1993), and composers (Hassler, 1992); many schizophrenics (Crow et al., 1996); specific alcoholic types (London, 1985) and many obese women are left-spectrum, old genotype individuals who can be located along specific places on the left end of the (- -) to (+ +) arc.  Several other conditions congregate at the right end of the left-right arc.  I believe that the human species moves through time inside a (- -) to (+ +) developmental arc, its character determined by the effects of sexual selection and the uterine environment on the rate and timing of development and maturation, creating the balanced polymorphism revealed by this Theory of Waves.

The process of evolution, the rules of species transformation, evolves.  The rules change.  Different rules apply to different species.  The rules become more intricate and subtle with an increase in complexity in hormonal systems.  Ancient species are still evolving exclusively according to random variation unlike more recently evolved complex species with longer ontogenetic histories.  Each species needs to be examined for its signature methods of transcending the random variation barrier.  Each human individual can be explored for his or her signature response to environmental messages mediated through a genetic history revealing a map of the responses of our past.

Investigate citations by proceeding to sexualselection.org.  There citation hotlinks will direct you to the cited quote from that author.


Comments

This entry was posted on Tuesday, December 30th, 2008 at 8:12 am and is filed under Biology, lefthanded, Neoteny, Ontogeny, Sexual Selection, Social Structure, Society. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
3 Comments so far

  1. Rob on January 4, 2009 1:21 am

    Regarding the modern age of procreation in urban environments being a result in change of diet, and thus causing some various problems:

    Historically, for instance in India until only recently, the age of procreation was around 14-15 for females. Fathers were anywhere from 14-15 up to 60.

    cultural changes that apply mainly to Europeans raised the procreation age higher and higher thru to the 1960’s, at which time it fell a little bit due to loosening of sexual mores.

    So, are you saying that all these problems of concern due to lower age of procreation have been present in India all this time?

    Cheers

  2. Andrew on January 4, 2009 8:34 am

    Age of procreation is not as relevant as pubertal timing, called progenesis in heterochonic theory. Pubertal timing seems to be influenced by both estrogen and testosterone and seems to be connected to several disease etiologies.

    I’m not really understanding your question regarding age of marriage and that not having changed over time in India.

  3. Rob on January 4, 2009 6:31 pm

    Hi:

    I think what I meant to say is that I suspect the onset of puberty in India today, as in the past, was sooner than currently in the West.

    I seem to remember from Anthropology 101 that most pre-industrial revolution peoples had an early puberty, early procreation, and early death relative to modern industrial civilizations.

    But I’m and electronic engineer so that’s really not my area of specialization.

    Another problem I find with your theories is that I really don’t think most depression in Western Cultures is medical, rather it is ideational. I have investigated this fairly well, and have dialogued with a lot of depressed, bipolar and some schizophrenic individuals, and more or less cured a man who was schizophrenic and on disability – no meds involved. That was a year ago and he is still doing fine and getting even better. I cured him with dialectic and meditation.

    And contrary to what is commonly published, many of the “clinically” depressed, bipolar and even some schizophrenics do recover, and generally it is due not to meds but to a change in world view. This has actually been well documented by psychologists, but in terms of percentage of publishings they are overwhelmed by the grim publishings from the bio-psychiatric model of mental illness, likely due to funding from Big Pharma.

    The onset of depression, bipolar and some schizophrenia seems to have a lot to do with parenting style, and early adult experiences doing battle with what is for the most part a very competitive and hostile society. Without a classical education most people are not equipped to do battle. Weak personality types that may be geneticly coded for fair worst.

    These mental illnesses are also caused by societal encouragement of narcissism (mostly coming from Madison Avenue), and then the frustration born of not being able to always extract enough vain validation from others to maintian a self-centric worldview. When vain validations are successful, neurotransmitters like serotonin and dopamine increase and one feels great. When the validations are frustrated neurotransmitters decrease and one feels lousy.

    As I said, none of this is all that new or unknown to the academic community, but there is no profit in telling people to live simply and soberly and stoicly and so those messages tend to be in short supply.

    Also, some of Freud’s and even Marx’s ideas about neurosis and unhappiness being tied to divorce from the land, hanging by the thread of the whim of others, I do think are accurate.

    Brain imagings and spinal fluid measurements of neurotransmitter levels never prove the medical or biological roots of mental illness but only show symptoms.

    The fact that mental illnesses seem to run in families to some degree does not by itself suggest genetic roots. At the most it suggests that in these family lines people screw with each other. Good parenting style has to be learned and in some cases is an asset built up over several generations. It can be lost in one generation due to certain unfortunate events.

    As I mentioned, your theory seems to overplay the role of hormones and underplay the role of cognitions. A lot of people with a mental illness are, only in the past few years, being successfully treated with Cognitive Behavioral Therapy or Dialectical Behavioral Therapy, which are both derived from Buddhism. Both therapies seek to change a person’s worldview.

    As for diabetes, Type 2 is coming to be widely understood as a symptom of wrong lifestyle, which is made easy by the easy access to an over-abundance of nutritionless carbohydrates. This problem is also addressed by changes in worldview or cognitions directing a person to force themselves to stick with, ideally, a primitive hunter-gatherer diet and get some exersize.

    As for diabetes type 1, I was not aware it is on the rise.

    As for autism, I know nothing about it. Some blame mercury.

    I don’t mean to disparage your entire estrogen/testosterone evolutionary theory add-on. I have read some of the material and it seems intriguing.

    But by the same reasoning you use, namely, that other factors can influence human evolution besides simple natural selection, there have been theories advanced that memory and cognition also play a role, perhaps a very big role, in modifying natural selection. Cognition and memory allow for groups to selectively breed. That seems to be how the Brahmins of India came to be, also the Mandarins in China. In these cultures mate self-selction was not the norm, rather, elders arranged the marriages, not unlike how animal breeders operate.

    While the Brahmins and Mandarins represent a “breeding up”, the creation of a sort of pedigree, the movie “idiocracy” shows how the societal excusing of ignorance and validation of every possible mind set leads to a breeding down, a return to being a bunch of dog-pound mutts.

    Finally:

    That masculine women marry feminine men has been commented on, even humorously, for some time. And of course the vice versa seems true. That part of your theory works, however, I think one has to account for the fact that such pairings are the result of games whereby, at least historically, at least one of a pair has to wear pants for the pair to be competitive or successful. That is a one strategy in a game that pits pairs against other pairs, groups against other groups, and against the difficult environment generally. That game can change as existence becomes easier.

    Generally:

    I think there is a lot of conflation hidden in your theory. Without fully examing the entire rube-goldgerg mechanism that we call interpersonal relations your broad brush stroke theory may hold for a time, but them fall apart due to some odd little change in an internal, presently conflated mechanism.

    Hopefully you will help to prevent autism – that’s a noble goal.

    Cheers

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