Testosterone is perhaps the only hormone with a personality, one that’s often blamed when violent things happen. It’s interesting to see a “biography” of it that’s so grounded in the biochemistry and the limits of what’s experimentally verifiable. The fact that testosterone is entwined into so many fates of growth and development makes it a hard subject for study.

One aspect that jumped out at me was the extent to which evolution creates mechanisms that are the opposite of engineered, for example having the same hormone control several systems that are to some extent in competition, or create systems that run-away without being inhibited (rather than stay quiescent without being stimulated).

Grounding to firmly in the biochemistry is also a weakness too, though: it’s a little too reductionist, a little too fast to dismiss psychology and how testosterone might affect feeling, and therefore affect behaviour indirectly beyond the strict biochemical pathways. I can accept that psychology is a hard regime in which to do fully-grounded experiments: but that’s true for all complex systems, and so its perhaps better to go looking for the general shapes of behaviour rather than focus so much on the details – and dismiss out of hand areas where these studies can’t be performed.

3/5. Finished Monday 28 March, 2022.

(Originally published on Goodreads.)