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Testosterone Increases Brain Activity According to Social Situation

Posted by jamesmhoward on 17 Oct 2012 at 12:30 GMT

It is my hypothesis that mammalian evolution was driven by increases in dehydroepiandrosterone (DHEA) and that human evolution is driven by increases in testosterone. That is, primate evolution was driven by increased selection for testosterone which culminated in human evolution. (“Hormones in Mammalian Evolution,” Rivista di Biologia / Biology Forum 2001; 94: 177-184; “Mitochondrial Eve,’ ‘Y Chromosome Adam,’ Testosterone, and Human Evolution,” Rivista di Biologia / Biology Forum 2002; 95: 319-326; “Androgens in Human Evolution,” Rivista di Biologia / Biology Forum 2001; 94: 345-362; ; if your library does not subscribe to “Rivista … ,” you may read this at )

It is my hypothesis that evolution selected dehydroepiandrosterone (DHEA) because it optimizes replication and transcription of DNA. Therefore, DHEA levels affect all tissues. That is, I suggest DHEA stimulates gene activity. I think testosterone was selected by evolution because testosterone increases androgen receptors which increase absorption of DHEA by cells / tissues. In the case of humans, it is maternal testosterone which produces the dramatic differences between humans and chimpanzees. That is, maternal testosterone increases androgen receptors in the brain which absorb DHEA at the expense of the body. Hence, our brains are bigger and our bodies are less robust as a result. (Human females and males produce more testosterone than chimpanzee females and males. There is not much difference in estradiol.)

The point of the foregoing material was to demonstrate that testosterone directs use of DHEA to tissues in a competitive manner. Now, this relates to Wibral, et al., in this manner. Testosterone increases function in a tissue, a part of the brain, that has been activated. Therefore, treatment with testosterone will increase the brain function that is being used. The situation described in Wibral, et al., causes stimulation of a particular part of the brain involved in the situation. I suggest this situation involved a “mind set” used by most individuals who “want to do the right thing.” In this case, “the right thing, expected by normal social situations” is to not lie. Therefore, I suggest that the increased activity stimulated by this situation directed the increase activity stimulated by increased testosterone. Therefore, this situation allowed testosterone to reduce the “socially expected” behavior of not lying.

I also suggest that increased testosterone increases activity in sexually active parts of the brain in most instances. In this case the competition for brain activity is increased in sexual activity, perhaps, at the expense of not lying.

No competing interests declared.