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How does the prenatal environment affect development
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Assignment two
Much research has been conducted looking into the area of the human anatomy of the lengths of digits on the hand, particularly research into the 2D:4D digit ratio. The 2D:4D is a sexually dimorphic trait found in humans Hömekopp and Watson (2010 from a meat-analysis) and refers to the lengths of the 2nd digit/ finger (pointer) and the 4th digit/ finger (ring) and it is believed that this length is predisposed from exposure to different hormones in the utero Manning (2002). It has been hypothesized that the 2D:4D is a biomarker that is caused from parental testosterone and parental estrogenic Manning (2002) and is believed that a child’s 2D:4D is fully formed within the first 13 to 14 weeks of pregnancy (Phelps. 1952). Knickmeryer and Manning (2004) found a negative association of the ratio between testosterone and estradiol in the amniotic fluid, on the other hand high testosterone to estradiol levels have been associated with smaller 2D:4D digit ratios. On the other hand higher 2D:4D digit ratio has been associated with higher levels of estradiol to testosterone Manning et al (1998). It has also been found that males have a slightly smaller digit ratio to women Baile (2004).
The 2D:4D digit ratio has been liked with a plethora of human behaviours such as aggression (Manning, 2013) and gender identity (Kangassalo, 2011). However there has been much research into the length of the 2D:4D digit ratio and individual differences to self-perceived attractiveness, self-esteem and body- esteem; particularly in women (wade, 2003). One of the most influential psychologist exploring this area was Wade who hypothesised that women with a high 2D:4D digit ratio would find themselves more attractive. To test this hypotheses Wa...
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... T., Stewart, A., Bundred, P. E., & Trivers, R. L. (2004). Sex and ethnic differences in 2nd to 4th digit ratio of children. Early Human Development, 80 (2), 161 – 168
Manning, J.T., Scutt, D., Wilson, J., and Lewis-Jones, D.I. (1998). The ratio of 2nd to 4th digit length: A predictor of sperm numbers and concentrations of testosterone, luteinizing hormone and oestrogen. Human Reproduction,13 , 3000–3004
Manning, J. (2013). Digit Ratio (2D:4D), Aggression, and Testosterone in M en Exposed to an Aggressive Video Stimulus. Evolutionary Psychology. 11 (5), pp 953 - 964.
Kangassalo, k. (2011). Prenatal Influences on Sexual Orientation: Digit Ratio (2D:4D) and Number of Older Siblings. Evolutionary Psychology. 9 (4), pp 496-508.
Baile, A. (2004). Finger length ratio (2D:4D) correlates with physical aggression in men but not in women. Biological Psychology. 5 (1), 2-3.
According to Giles and Elliot individual CR13304 was calculated to be Male. In order to too be a male according to this method the select cranial measurements must total higher than a sum of 891.12 when placed into a series of formulae. After the sex of the indi...
Various previous studies found that girl and boys have different type of toys preferences that can be learned through modeling and reinforcement. There are also biological factors that influence the differences between girls and boys. Gonadal hormones highly influence the development of sex differences in terms of behavior and in the brain at different species of animals. There is a unique case where females with genetic disorder congenital adrenal hyperplasia (CAH) –highly exposed to adrenal androgens before birth –shows a more manly behavior and physical energy with higher spatial ability than normal females. Other findings also show similar results caused by masculine hormones by maternal ingestion during pregnancy.
5. Kellert, S.R. and E.O. Wilson, editors. 1993 The Biophilia Hypothesis. Island Press, Washington, DC
...f Violent Video Games on Aggression: Is it More Than Just the Violence? Aggression and Violent Behavior, 55-62.
I will conclude this paper by discussing some of the behavioral traits that have been thought to correlate with differing degrees of sexual dimorphism and their plausibility. Anatomical Structures Used to Study Human Sexual Dimorphism To discuss sexual dimorphism, one must first define the term. Webster’s Dictionary defines sexual dimorphism as “the condition in which differences i... ... middle of paper ... ...
Oestrogen receptors in the brain are believed to cause gender-appropriate behaviour. Oestrogen, a hormone found in the female genital tissue, acts as a ligand and, by activating the oestrogen receptors found on the surfaces of brain cells, causes notable changes in behaviour. Professors at Yale University have studied the effects of oestrogen and found the hormone increases neural connectivity in the brain resulting in a more accurate memory. Turnham et al (2002) supports this as upon investigation...
Swaab, Df. "Sexual Differentiation Of The Human Brain: Relevance For Gender Identity, Transsexualism And Sexual Orientation." Gynecological Endocrinology 19.6 (2004): 301-312. Informa Healthcare . Web. 7 Apr. 2014.
What controls a human's sexual orientation? The long-standing debate of nature versus nurture can be extended to explaining human sexual orientation. Is it biological or environmental? The biological explanation has been gaining popularity amongst the scientific community although it is only based on speculations. It is argued that sexual orientation is linked to factors that occur during sexual differentiation. The prenatal exposure to androgens and their affect on the development of the human brain play a pivotal role in sexual orientation (2). Heredity is also part of the debate. Does biology merely provide the slate of neural circuitry upon which sexual orientation is inscribed? Do biological factors directly wire the brain so that it will support a particular orientation? Or do biological factors influence sexual orientation only indirectly?
Bandura, A., Ross, D., & Ross, S.A. (1961). Transmission of aggression through imitation of aggressive models. Journal of Abnormal and Social Psychology, 63, 575-582.
In 1991, a behavioral geneticist, Michael Bailey, proposed that genes may contribute to homosexuality in males (Wickelgren, 1999). Bailey found that 52% of identical male twins were homosexual compared to 22% of fraternal male twins (Wickelgren, 19...
Pan, H. S., Neidig, P. H., & O'Leary, K. D. (1994). Predicting mild and severe husband-to-wife physical aggression. Journal of Consulting and Clinical Psychology, 62(5), 975-981. Retrieved from http://dx.doi.org/10.1037/0022-006X.62.5.975
Swerdloff RS, Wang C. The testis and male sexual function. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011: chap 242.
The X-chromosome is one of the two sex chromosomes(the other being Y) that is responsible for a variety of factors in a child’s developmental growth, the most commonly known being their biological sex. Researchers at the National Center for Biotechnology Information have studied the X-chromosome and its relation to homosexuality in men. Preceding their studies, the researchers hypothesized, “If the X Chromosome contains a gene that increases the probability of an individual’s being homosexual, then genetically related gay men should share X chromosome markers close to that gene. If no such gene exists, then no statistically significant correlations between sexual orientation and X chromosome will be observed” (Bocklandt, Horvath, Vilain, Hamer).
Behavior, Aggressive Cognition, Aggressive Affect, Psychological Arousal, and Prosocial Behavior: A Meta- Analytic Review of the Scientific Literature.” soc.iastate.edu. vol.12, No.5, September 2001. Copyright 2001 American Psychological Society. Web. 20 November 2011.
3. 3}Are There Differences between the Brains of Males and Females?,Intellectual differences among the sexes.