It makes me wonder if there are different degrees of "maleness" and "femaleness" of various brains and if this in any way affects predispositions to particular behavioral patterns.
You got it. Well expressed too, this isn't binary, different parts of the brain conform more or less to a male/female average or stereotype, no-one is 100% M or 100% F in all respects.
Obviously people exist on a variety of spectra, but I am curious as to exactly how much influence brain structure has on where they fall on them.
Quite a lot. However many parts of the brain are plastic to some degree, so there's feedback involved.
As a general rule, when it comes to "Gendered behaviour", most of it has no biological basis. Most - but perhaps 20% or so does, and this 20% is quite important. While it does cover some problem-solving, 3D visio-spatial relationship perception, language ability and other easily measurable areas, a bigger part is to do with emotional response, body language, "instincts" for want of a better term.
So while it's a good first approximation to say that Gender is entirely a social construct, that there are no differences, that approximation soon breaks down.
This is most glaringly, blindingly obvious in some Intersex conditions, where we know neurological development is anomalous in the area of sexual dimorphism. I'll give 3 examples:
Turner syndrome : women with 45,X rather than 46,XX chromosomes
Mental retardation is not a feature of Turner syndrome, despite such claims in older medical textbooks. Thorough psychological studies show that these women are normal intellectually, but often have a characteristic pattern of intellectual functioning. While their verbal IQ usually is average or above, their non-verbal IQ may be considerably lower because of problems visualizing objects in relation to each other. This difficulty may show up in poor performance in math, geometry, and tasks requiring manual dexterity or sense of direction.- Turner Syndrome -- Human Growth Foundation.
Klinefelter syndrome - usually caused by males having 47,XXY not 46,XY chromosomes:
Although they are not mentally retarded, most XXY males have some degree of language impairment. As children, they often learn to speak much later than do other children and may have difficulty learning to read and write. -- Understanding Klinefelter Syndrome -- National Institute of Child Health and Human Development.
Whether you regard such people as "genetic women" masculinised by a Y chromosome (as is the official position of the Indonesian Catholic Bishops), or "genetic men" feminised by an extra X chromosome is a matter of ideology and faith, not fact. Most are just men, a few are women.
CAH - Congenital Adrenal Hyperplasia in females
Data show that increased male-typical toy play by girls with CAH cannot be explained by parental encouragement of male-typical toy play. Although parents encourage sex-appropriate behavior, their encouragement appears to be insufficient to override the interest of girls with CAH in cross-sexed toys.Prenatal hormones versus postnatal socialization by parents as determinants of male-typical toy play in girls with congenital adrenal hyperplasia Pasterski VL, Geffner ME, Brain C, Hindmarsh P, Brook C, Hines M
Child Dev 76(1):264-78 2005
http://www.neuroscience.cam.ac.uk/publications/pubInfo.php?foreignId=pubmed%3A15693771
For example, I am a fairly androgynous woman, I prefer styles of clothing that are more traditionally masculine and I am extremely uncomfortable in anything feminine (dresses are right out). I am also told that my behavioral patterns when it comes to sex and relationships are rather male. However, despite all that I very much identify as a woman. There is no question in my mind that I am a woman, but how I express it is somewhat atypical. I'd be interesting to know how much of this is rooted in basic brain structures. As always I am interested in the dynamic between innate characteristics (or at least predispositions) and learned behavior and the biofeedback loop between brain structure and behavior/experience. Our brain structure effects our behavior and our behavior and experiences in turn effect the structure of our brains.
Quoted in entirety, as no expert in the area could have put it better.
Some parts of the brain are plastic to varying degrees. Some parts aren't, but even then, pubescent changes happen there in some parts. It's a 1-way trip though, the pattern of development predestined or organised by hormonal variation in the womb, only activated later.
The organisation/activation model is very powerful, and is considered proven for nonhuman mammals, and nearly proven for humans."Nearly" as to prove it would require unethical experimentation on human fetuses, real Dr Mengele stuff.
The organization-activation theory posits that the nervous system of a developing fetus responds to prenatal androgens so that, at a postnatal time, it will determine how sexual behavior is manifest. How organization-activation was or was not considered among different groups and under which circumstances it is considered is basically understood from the research and comments of different investigators and clinicians. The preponderance of evidence seems to indicate that the theory of organization-activation for the development of sexual behavior is certain for non-human mammals and almost certain for humans.Clinical Implications of the Organizational and Activational Effects of Hormones M.Diamond
Hormones and Behavior 55 (2009) 621–632
http://www.hawaii.edu/PCSS/biblio/articles/2005to2009/2009-clinical-implications-hormones.htmlHow much of your psychology is rooted in innate brain structure? At an informed guess, most. The Gender Identity, certainly. You
know you're female, as does Claire, as do I, despite evidence existing to the contrary. In your case "male typical" behaviour, in my case too to a lesser extent, in Claire's case and mine too the whole "MAAB" thing. Your "male typical" behaviour is very similar to women with CAH - I have CAH BTW, just not the usual kind.( 95% of CAH is caused by 21H, 5% by 11B, <1% by all other causes (3BHSD,17AH,Lipoid). I have 3BHSD)
How do we "know" what sex we are? This paper explains it:
A theory of gender development is presented that incorporates early biological factors that organize predispositions in temperament and attitudes. With activation of these factors a person interacts in society and comes to identify as male or female. The predispositions establish preferences and aversions the growing child compares with those of others. All individuals compare themselves with others deciding who they are like (same) and with whom are they different. These experiences and interpretations can then be said to determine how one comes to identify as male or female, man or woman. In retrospect, one can say the person has a gendered brain since it is the brain that structures the individual’s basic personality; first with inherent tendencies then with interactions coming from experience. Biased-Interaction Theory of Psychosexual Development: “How Does One Know if One is Male or Female?” M.Diamond
Sex Roles (2006) 55:589–600
http://www.hawaii.edu/PCSS/biblio/articles/2005to2009/2006-biased-interaction.htmlIt's obvious though that you've already grasped the essentials, and have some idea of the complexities.
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Topic: WCDT: 2401-2405 (11-15 March, 2013) Weekly Comic Discussion Thread (Read 80704 times)