Jump to content

Biology of gender-specific human behavior: Difference between revisions

Add links
From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
Merged intelligence info to main article, and made a summary of that article
m →‎Research: copyed
Line 13: Line 13:
<p>The late twentieth century saw an explosion in technology capable of aiding sex research. [[John Money]] and [[Milton Diamond]] made great progress towards understanding the formation of [[gender identity]] in [[human]]s. Extensive advances were also made in understanding sexual dimorphism in other animals. For example, there were studies on the effects of [[sex steroid|sex hormone]]s on rats. The early twenty first century started producing even more amazing results concerning [[genetic programming|genetically programmed]] sexual dimorphism in rat brains, prior even to the influence of hormones on [[developmental biology|development]].</p>
<p>The late twentieth century saw an explosion in technology capable of aiding sex research. [[John Money]] and [[Milton Diamond]] made great progress towards understanding the formation of [[gender identity]] in [[human]]s. Extensive advances were also made in understanding sexual dimorphism in other animals. For example, there were studies on the effects of [[sex steroid|sex hormone]]s on rats. The early twenty first century started producing even more amazing results concerning [[genetic programming|genetically programmed]] sexual dimorphism in rat brains, prior even to the influence of hormones on [[developmental biology|development]].</p>
{{cquote|Genes on the [[sex chromosome]]s can directly influence sexual dimorphism in [[cognition]] and behaviour, [[Statistical independence|independent]] of the action of sex steroids.}}
{{cquote|Genes on the [[sex chromosome]]s can directly influence sexual dimorphism in [[cognition]] and behaviour, [[Statistical independence|independent]] of the action of sex steroids.}}
{{cite journal|last=Skuse|first=David H|title=Sexual dimorphism in cognition and behaviour: the role of
<ref>{{cite journal|last=Skuse|first=David H|title=Sexual dimorphism in cognition and behaviour: the role of
X-linked genes|journal=European Journal of [[Endocrinology]]|volume=155|pages=99-106|date=2006}}
X-linked genes|journal=European Journal of [[Endocrinology]]|volume=155|pages=99-106|date=2006}}</ref>

<p>Some specific relevant [[result]]s are as follows. The brains of many animals, including humans, are [[statistical significance|significantly]] different for [[male]]s and [[female]]s of the [[species]] (Goy and McEwen, 1980).<ref>[https://mitpress.mit.edu/catalog/item/default.asp?ttype=2&tid=10042&mode=toc Robert W Goy and Bruce S McEwen. ''Sexual Differentiation of the Brain: Based on a Work Session of the Neurosciences Research Program''. MIT Press Classics. Boston: MIT Press, 1980.]</ref> Both [[genes]] and [[hormone]]s affect the formation of many animal brains before "[[birth]]" (or [[hatching]]), and also behaviour of adult individuals. Hormones significantly affect human brain formation, and also brain development at puberty. Both kinds of brain difference affect male and female behaviour.</p>
Some specific relevant [[result]]s are as follows. The brains of many animals, including humans, are [[statistical significance|significantly]] different for [[male]]s and [[female]]s of the [[species]] (Goy and McEwen, 1980).<ref>[https://mitpress.mit.edu/catalog/item/default.asp?ttype=2&tid=10042&mode=toc Robert W Goy and Bruce S McEwen. ''Sexual Differentiation of the Brain: Based on a Work Session of the Neurosciences Research Program''. MIT Press Classics. Boston: MIT Press, 1980.]</ref> Both [[genes]] and [[hormone]]s affect the formation of many animal brains before "[[birth]]" (or [[hatching]]), and also behaviour of adult individuals. Hormones significantly affect human brain formation, and also brain development at puberty. Both kinds of brain difference affect male and female behaviour.</p>
[[Image:Normal distribution pdf.png|thumb|left|200px|Comparing Groups]]
[[Image:Normal distribution pdf.png|thumb|left|200px|Comparing Groups]]
<p>Brain differences also have a statistically measurable effect on an array of [[ability|abilities]]. In particular, on average, men are more capable in space and logic while female brains tend to be good at [[senses|sensory]] processing. These are examples of different [[average]]s between two [[statistics|statistical]] populations (like pink and red in the diagram). On the other hand, the average scores of young men and women in mathematics, for example, will be close, but there will be more men than women in the very low scores and in the very high scores (like green and red, or blue and red in the diagram).<ref>Camilla Persson Benbow and Julian C Stanley, 'Sex Differences in Mathematical Reasoning Ability: More Facts', ''Science'' 222 (1983): 1029-1031.</ref> There is evidence to suggest that forms of [[autism]] may be essentially extreme expressions of certain typically male characteristics.<ref>
<p>Brain differences also have a statistically measurable effect on an array of [[ability|abilities]]. In particular, on average, men are more capable in space and logic while female brains tend to be good at [[senses|sensory]] processing. These are examples of different [[average]]s between two [[statistics|statistical]] populations (like pink and red in the diagram). On the other hand, the average scores of young men and women in mathematics, for example, will be close, but there will be more men than women in the very low scores and in the very high scores (like green and red, or blue and red in the diagram).<ref>Camilla Persson Benbow and Julian C Stanley, 'Sex Differences in Mathematical Reasoning Ability: More Facts', ''Science'' 222 (1983): 1029-1031.</ref> There is evidence to suggest that forms of [[autism]] may be essentially extreme expressions of certain typically male characteristics.<ref>

Revision as of 07:53, 8 July 2007

Human Brain

The biology of gender is scientific analysis of the physical basis for behavioural differences between men and women. It is more specific than sexual dimorphism, which covers physical and behavioural differences between males and females of any sexually reproducing species. Biological research of gender has explored such areas as: intersex physicalities, gender identity, gender roles and sexual preference. Late twentieth century study focussed on hormonal aspects of the biology of gender. With the successful mapping of the human genome, early twenty-first century research started making progress in understanding the effects of gene regulation on the human brain.

Sex and intelligence

Main article: Sex and intelligence

Although men have a larger brain size, there is no definite indication that men are more intelligent than women. In contrast, women have a higher density of neurons in certain parts of the brain.

However, difference is seen in the ability to perform certain tasks. Females are superior on various measures of verbal ability, while males have specific abilities on measures of mathematical and spatial ability.

Research

Male-Female Differences

It has long been known that there are correlations between the biological sex of animals and their behaviour.[1] [2] [3] It has also long been known that human behaviour is influenced by the brain.

The late twentieth century saw an explosion in technology capable of aiding sex research. John Money and Milton Diamond made great progress towards understanding the formation of gender identity in humans. Extensive advances were also made in understanding sexual dimorphism in other animals. For example, there were studies on the effects of sex hormones on rats. The early twenty first century started producing even more amazing results concerning genetically programmed sexual dimorphism in rat brains, prior even to the influence of hormones on development.

Genes on the sex chromosomes can directly influence sexual dimorphism in cognition and behaviour, independent of the action of sex steroids.

[4]

Some specific relevant results are as follows. The brains of many animals, including humans, are significantly different for males and females of the species (Goy and McEwen, 1980).[5] Both genes and hormones affect the formation of many animal brains before "birth" (or hatching), and also behaviour of adult individuals. Hormones significantly affect human brain formation, and also brain development at puberty. Both kinds of brain difference affect male and female behaviour.

Comparing Groups

Brain differences also have a statistically measurable effect on an array of abilities. In particular, on average, men are more capable in space and logic while female brains tend to be good at sensory processing. These are examples of different averages between two statistical populations (like pink and red in the diagram). On the other hand, the average scores of young men and women in mathematics, for example, will be close, but there will be more men than women in the very low scores and in the very high scores (like green and red, or blue and red in the diagram).[6] There is evidence to suggest that forms of autism may be essentially extreme expressions of certain typically male characteristics.[7] [8] Hormones have also been linked with male aggression.[9]

There is a lot of variation in men and women that is not yet understood. It cannot be proven that male-ness or female-ness is 100% biological (in fact it almost certainly isn't), but what has been shown is that male-ness and female-ness are certainly not 100% determined by upbringing and culture (social determinism). These issues remain an area of ongoing research, with profound relevance for people of many different types.

For an illustrated description of clear differences between male and female brain response to pain see Laura Stanton and Brenna Maloney, 'The Perception of Pain', Washington Post, 19 December 2006.

In 2006, Alexandra M. Lopes and others published that:

A sexual dimorphism in levels of expression in brain tissue was observed by quantitative real-time PCR, with females presenting an up to 2-fold excess in the abundance of PCDH11X transcripts. We relate these findings to sexually dimorphic traits in the human brain. Interestingly, PCDH11X/Y gene pair is unique to Homo sapiens, since the X-linked gene was transposed to the Y chromosome after the human–chimpanzee lineages split.[10]

Research and ethics

Research Laboratory

One important thing to note about the biological research is that most of it was generally motivated by seeking the causes of diseases in human beings, and ways of treating or preventing those diseases. For example, there is study into genetic predisposition to, or causes of, Alzheimer's disease and mental illnesses. Also:

Scientists have cracked the code of an essential signal in the sequence of steps that controls the molecular choreography of gene regulation. The discovery is expected to aid development of therapies and prevention strategies for certain genetically triggered diseases such as breast cancers, pediatric cancers, and leukemia.

Kennedy, Barbara K (2001). "Key Step in Gene Activation Discovered". Science Journal. 18.

Research results are relevant to gender issues, but that is not their direct concern. Sexual dimorphism in the brain is important to study, because we may need to apply different kinds of treatment to women and to men. Injections for tetanus work the same for men and women, but involve biological intervention to promote health.

Perhaps one day science may be able to tell us how we could stop male dominance by biological intervention; but science can't tell us if male dominance is a kind of disease. This takes us back to the importance of the moral questions. Pierre Bourdieu, in 1998 wrote:

Male domination is so rooted in our collective unconscious that we no longer even see it. It is so in tune with our expectations that it becomes hard to challenge it. Now, more than ever, it is crucial that we work to dissolve the apparently obvious and explore the symbolic structures of the androcentric unconscious that still exists in men and women alike. What are the mechanisms and institutions which make possible the continued reproduction of this age-old domination by men? And is it possible to neutralise them in order to liberate the forces for change which they are instrumental in blocking?[11]

So, if an injection could remove male dominance behaviour, should it be made law for such an injection to be given? Should parents be given the choice, or only mothers? These are ethical questions normally thought to require informed debate. The text of this article has provided information from a number of sources, and recorded different positions offered in the debate so far. There are still many unknowns, but new research is being both conducted and published every year. One new journal (available since 2002) is devoted exclusively to Genes, Brains and Behavior. More literature is provided below.

See also

References

  1. ^ Charles Darwin, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, (London: John Murray, 1859).
  2. ^ Charles Darwin, The Descent of Man, and Selection in Relation to Sex, 2 volumes, (London: John Murray, 1871).
  3. ^ Helena Cronin, The Ant and the Peacock: Altruism and Sexual Selection from Darwin to Today, (Cambridge: Cambridge University Press, 1991).
  4. ^ Skuse, David H (2006). "Sexual dimorphism in cognition and behaviour: the role of X-linked genes". European Journal of Endocrinology. 155: 99–106. {{cite journal}}: line feed character in |title= at position 58 (help)
  5. ^ Robert W Goy and Bruce S McEwen. Sexual Differentiation of the Brain: Based on a Work Session of the Neurosciences Research Program. MIT Press Classics. Boston: MIT Press, 1980.
  6. ^ Camilla Persson Benbow and Julian C Stanley, 'Sex Differences in Mathematical Reasoning Ability: More Facts', Science 222 (1983): 1029-1031.
  7. ^ Simon Baron-Cohen, 'The Extreme-Male-Brain Theory of Autism', in H Tager-Flusberg (ed.), Neurodevelopmental Disorders, (Boston: The MIT Press, 1999).
  8. ^ Simon Baron-Cohen. Mindblindness: An Essay on Autism and Theory of Mind. (Boston: The MIT Press, 1997).
  9. ^ Elizabeth J. Susman, Gale Inoff-Germain, Editha D. Nottelmann, and others, 'Hormones, Emotional Dispositions, and Aggressive Attributes in Young Adolescents', Child Development 58 (1987): 1114-1134.
  10. ^ Alexandra M. Lopes and others,'Inactivation status of PCDH11X: sexual dimorphisms in gene expression levels in brain', Human Genetics 119 (2006): 1–9.
  11. ^ Pierre Bourdieu, 'On Male Domination', Le Monde Diplomatique English edition (October 1998).

External links

Literature

  • Baron-Cohen, Simon. The Essential Difference: The Truth about the Male and Female Brain. New York: Perseus Books Group, 2003.
  • Brizendine, Louann. The Female Brain. New York: Morgan Road Books, 2006.
  • Brown, Donald E. Human Universals. New York: McGraw Hill, 1991.
  • Kimura, Doreen. Sex and Cognition. MIT Press, 1999.
  • Moir, Anne and David Jessel. Brain Sex: The Real Difference Between Men and Women.
  • Pinker, Steven. The Blank Slate: A Modern Denial of Human Nature. London: Penguin Books, 2002.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Biology_of_gender-specific_human_behavior&oldid=143256397"