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more on hormones, bonobos and humans

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So having recently read Carole Hooven’s Testosterone: the hormone that dominates and divides us, an extremely informative and well-argued book that was basically a necessary read for me, considering my obsession with a more bonobo-like world for humans, I’m left with – what to do? How can I incorporate all this hormonal stuff into my ‘bonobo world and other impossibilities’ essays? I know I’ve mentioned hormones here and there, but never in any detail. Basically I’ve noted, along with Steven Pinker and others, that ‘we’re getting better’. Less violent, more caring of our children, more appreciative of our ‘feminine’ side, more questioning of the nature of gender, a little less male-dominant, at least in the WEIRD world. And since this doesn’t seem to have involved hormones, at least on the face of it, the testosterone issue was never so much front and centre in my dreams of human transformation as was the example, largely ignored by the human world, as it seems to me, of bonobo society.

Sadly, Hooven hardly mentions bonobos, so I need to do some bonobo-testosterone research myself. Here are my initial thoughts. Since bonobos, along with chimps, are our closest rellies, it’s reasonable to assume that we’re hormonally very similar (research required). So how did they evolve into the make-love-not-war apes (yes, an over-simplifying cliché), and why did we evolve more along the chimp line (yes, with great diversity, but very few cultures that ‘aped’ bonobos)?

Again, before I start looking at research abstracts, I can surmise a little. Chimps eat more meat than bonobos, which means more hunting and killing. Testosterone helps with that. The males are more into it so they gang together, leaving the women – sorry, the females – behind. There will be teamwork but also show-offy competition and a muscular hierarchy within the team. And the excitement of the hunt will boost testosterone all the more, which will be worked off on the females afterwards. Bonobos on the other hand spend more time in the trees, in a relatively nutrient-rich part of the DRC rainforest, eating mostly fruit and nuts. Not the sort of stuff you have to chase around and bash to death. And they hang around together, so the males might spend more time entertaining the kids, more or less by default.

And there are mysteries. The male bonobos are bigger than the females, by about the same proportion as humans. The females keep control by female-female bonding, often sexualised, but since ‘sexual healing’ goes on in every possible combination, why don’t the males gain control by the same means? Or why haven’t they? (It wouldn’t be a matter of deciding to do so, more an evolved thing, which didn’t happen). Also dominant females appear to have favoured male offspring, who might serve as their captain-at-arms, in a sense. But now I’m starting to speculate more wildly.

So, the research: in 2010, a paper was published in PNAS (pronounced ‘penis’ by the cognoscenti), entitled ‘Differential changes in steroid hormones before competition in bonobos and chimpanzees’. It described an experiment conducted on male pairs of chimps and bonobos (chimp with chimp, bonobo with bonobo). The pairs were tested for hormonal changes before and after two different food-sharing settings:

We found that in both species, males showed an anticipatory decrease (relative to baseline) in steroids when placed with a partner in a situation in which the two individuals shared food, and an anticipatory increase when placed with a partner in a situation in which the dominant individual obtained more food.

However, these ‘endocrine shifts’ occurred in cortisol for bonobos, and testosterone for chimps, which was more or less as predicted by the researchers. And why did they predict this?

Given that chimpanzees and bonobos differ markedly in their food-sharing behavior, we predicted that they would differ in their rapid endocrine shifts.

Cortisol is generally regarded as a stress hormone, or the fight or flight hormone. I used to get one of those ‘shifts’ (which sent me to the toilet) before teaching a new class. I haven’t asked female teachers if they ‘suffered’ similarly.

Because competition for overt markers of status and mating opportunities is more relevant to males, these effects are less consistent in females.

I’m not sure I was concerned about mating opportunities when starting a new class – could get me into a spot of bother – but status, maybe. But what interests me is that hormone shifts follow social behavioural patterns. That’s to say, shifts in testosterone will be rapid in all-male groups such as male gangs (which I experienced as a young person), in which the pecking order is constantly under challenge, all the way down the line. Cortisol too, I suppose, but gangs are all about ‘proving manhood’, which didn’t at the time seem to be all about sex, but in a not-so-roundabout way, it was.

Chimps, as mentioned, tend to hang together in these sorts of tight hierarchical groups, and so show a stronger ‘power motive’, a term used in human competition research. Bonobos are more co-operative, to the point of becoming stressed when food isn’t easily shared:

Because bonobo conflicts rarely escalate to severe aggression, we might classify bonobos as possessing a passive coping style…

That sounds like me, especially in my youth – considering that, all through my school years, I was one of the two or three smallest kids in the class, male or female, what other coping style could I have? But unfortunately, in the human world, too many blokes have an active coping style, together with a power motive, making misérables of the rest of us.

So, I’ve focused only on this one piece of research for this little essay, and I’ll have a look at more in the future. What it tells me is that we can, indeed, and should, shape our society to become more bonoboesque in the future, for the good of us all. It is heading that way anyway (again with that WEIRD world caveat), in spite of the Trumps and their epigones (dear, the idea that Old Shitmouth could bring forth epigones is grossly disturbing). One last quote from the researchers:

These findings suggest that independent mechanisms govern the sensitivity of testosterone and cortisol to competition, and that distinct factors may affect anticipatory vs. response shifts in apes and humans. Future species comparisons can continue to illuminate how ecology has shaped species differences in behavioral endocrinology, including the selection pressures acting in human evolution.
And of course human evolution continues…

can’t get enough of bonobo bonding

References

Carole Hooven, Testosterone: the hormone that dominates and divides us, 2021

https://ussromantics.com/category/bonobos/

https://www.pnas.org/doi/10.1073/pnas.1007411107

 

Written by stewart henderson

November 1, 2022 at 10:52 pm