@ifIwerenotanandroid
Wasn't there a study years ago, with football supporters, which found that the men with lower levels of testosterone were more violent? I only remember it because it seemed to be unusual/counter-intuitive.
I'd have to read the book.
I recall quite an interesting study on Tsimane men who are notable for (comparatively) stable amounts of testosterone across their lifespans. This is associated with low incidence of obesity, heart disease and other illnesses linked with aging in other communities. Anthropologists explain this in the context of their environment. Crudely, high levels of testosterone compromise the male immune system, so it is narrative commonsense to maintain it at a stable level in environments where parasites and pathogens are frequently encountered.
It is relatively recently that the physical extravagance of having substantial spikes and fluctuations or sustained high levels of T has been acceptable because there are now societies and social roles that do not expose men to high levels of pathogens and parasites (remote Bolivia).
However, it was interesting to see that the Tsimane spiked T when involved in organised competition (arranged by the authors, iirc). Up by 30% immediately after the game and still 15% an hour later.*
*Lots of confounders apply, including the testing method [
reasons ] but it's quirky which is why it's stuck with me.
Full paper is open access:
royalsocietypublishing.org/doi/pdf/10.1098/rspb.2012.0455
Trumble, B., Cummings, D., von Rueden, C., O’Connor, K., Smith, E.A., Gurven, M., Kaplan, H. 2012. Physical competition increases testosterone among Amazonian forager-horticulturalists: a test of the 'challenge hypothesis'. Proceedings of Royal Society B 279:2907-2912.