Answer to Question 1Answer: The student has a choice of four problems mentioned in the textbook, though they may come up with some of their own also. A basic outline of those discussed in the textbook include:
- An obvious issue is that all the gay men in LeVays study died of AIDS and there is the possibility that AIDS, or its treatment, was the cause of changes in the hypothalamus. LeVays answer is that some of his control group of straight men also died of AIDS and when you just compare gay men who died of AIDS to straight men who died of AIDS, you find the same differences in the hypothalamus.
- This, however, leads to the second methodological problem, which is that he did not actually ask the straight men about their sexual orientations, but presumed they were straight. His response is that if he had gay men in is his heterosexual male control group it would only have made it harder to find a significant difference, not easier.
- Some have suggested that LeVay should have included lesbian women in his study, but that was not the purpose of the study. It is an excellent idea for future study.
- A serious problem with the study is that it is basically a correlation. At best it is a quasi-experimental field study, not a true experiment. It is possible that the structure of the hypothalamus, in this case, was not the cause of homosexuality, but rather that a lifetime of homosexual behavior caused a structural change in this brain region. Solving this issue is quite difficult. You cant set up an experiment in humans and the sexual behavior of any other mammals is not the same as that of humans. The textbook suggests the use of PET scans and MRIs, which at least means you can study brain structure without having to wait for death to have access to data.
Answer to Question 2Answer: Simon LeVay was the first researcher to find clear evidence of a difference in the brains of gay men when compared to a random sample of other men and women. He found differences in a brain region, the hypothalamus, that is connected to sexual arousal, gender identity, and a variety of sexual disorders. In 1991 he studied 18 men who were gay and had died of AIDS, and 16 men who were presumed to be heterosexual, and 6 women. He replicated a previous finding that the third interstitial nucleus of the anterior hypothalamus (INAH-3) was less than half as large in heterosexual women as in heterosexual men. He also found that this region, in gay men, was indistinguishable from that of heterosexual women and was also half the size of heterosexual men. This suggests the possibility that at some point in brain development the INAH-3 of gay men, their hypothalamus developed in a different than in potentially heterosexual men, and that this difference in brain structure is one of the causes of many of the attitudes, perceptions, and sexual orientation of gay men.
The U.S. Long-Term Ecological Research (LTER) network.
Some organisms used as models in genetic research
Chair made from tree
An experimentally made Oldowan type core.
Research Methods: Advantages and Limitations
With the research technique called brainbow, each neuron is labeled with a different color, ...