Testosterone Makes Transmen Sing Louder?
One of the most interesting parts of science, for me, is in seeing how seemingly odd or pointless studies can have more important or more real-world applications. So it is with this paper, published recently in the Proceedings of the National Academy of Sciences.
T implants in the medial preoptic nucleus (POM) of castrated male canaries (Serinus canaria) increase song rate but do not enhance acoustic features such as song stereotypy compared with birds receiving peripheral T that can act globally throughout the brain.
This is far from the first study done looking at the effects of testosterone on castrated songbirds, just the most recent. These avian castrati have been doing their part for science!
The larger point to studies like this is to look at the ways testosterone affects sociosexual behavior. Hormone activity in birds is considered to be biologically similar to humans, and so learning how T affects songbirds can open windows into how T affects humans. To whit: learning specifically the ways in which T changes the behavior of songbirds in trying to attract mates can help us understand why teenage boys do stupid things to impress girls. [Or something like that :). ]
The other reason I find studies like this interesting is that a lot of “facts” surrounding the effects of HRT on transgender individuals are not drawn from direct research study of people undergoing transgender HRT, but inferred from studies like this. Testosterone makes birds more aggressive in trying to impress a mate; such behavior is also seen in male humans when their T levels rise in puberty, so it’s fair to infer that the mechanism is similar; and since transmen take steps to elevate their T levels to cismale levels. Which is all very common sense, but it does reveal a telling point: there’s very little that has been directly observed under scientific conditions.
Having more direct study of the effects of HRT on transmen and transwomen is something science will hopefully get to some day. Until then, we have to rely on analogy, indirect inference, and what little birds tell us.