a bonobo humanity?

The subversive family, a book written by Ferdinand Mount some 40 years ago, argues that the basic family unit, with two or, more rarely, three generations housed together, is indeed more basic than a great many critics allow, and that marriage based on mutual attraction has been more common throughout human history than many historians claim. However that may be, he makes no mention of prehistory, by which I mean the long period of human, and early hominid, existence, before the invention of writing.

What interests me is the nature of sexual relationships during that period, and that nature is hardly likely to have been static. Clearly, marrying is a ceremonial act, which requires a certain level of sophistication. It is apparently intended to ‘tie the knot’, to formalise two persons’ commitment to each other, a commitment expected to be lifelong. Ideally, this commitment is based on love.

It’s interesting that many bird species are monogamous. They stay together, with only the occasional bit on the side, build nests together, share the feeding and teaching of the kids and so on. We talk of love-birds, we love the willow pattern tale, but do we really think these birds love each other? Probably not, because we like to reserve this state of being for humans.

This human specialness thing is eroding though. Dogs mourn their human owners. Elephants grieve over their companions and their children. The more we look at complex social species, the more we find evidence of deep feeling which we may or may not call love, though to call it something other than love would seem insensitive.

But marriage, freely entered into, is about romantic love, and that, some say, is singularly human. Others, of course, say romantic love is a myth, a mixture of hormones and psychology that doesn’t last, though the commitment might continue after the passion is spent, especially where children are involved.

This monogamous arrangement has proved effective for the raising of offspring, in humans as well as in swans, cranes and eagles, and in prairie voles, Azara’s night monkeys and a few other mammalian species. However other complex social animals, such as elephants, dolphins and chimps, are not monogamous, and in fact only about 3% of mammals practice monogamy, and they still manage to raise their young just fine. I have a special interest in bonobos, our closest living relatives, on a par with chimps. They are highly sexualised, yet manage to avoid getting pregnant more than is needful. Females dominate in spite of sexual dimorphism which favours males. Are bonobos, Pan paniscus, a more loving species than Homo sapiens? I leave aside our species’ predilection for aggression and warfare, I’m considering the comparison in times of relatively peace for both species. It is probably impossible to make such a comparison, social contexts are perhaps too different, and bonobos are an endangered species, and quite difficult to study in the wild. As to human apes, it seems that in our human history, which dates back to the development of writing as an effective information and communication tool, we have been almost universally patriarchal and monogamous. But this takes us back only a few thousand years. Our species is at most about 300,000 years old – there’s a lot of debate about this – and tracing our ancestry back to its connection with the bonobo-chimp line has been problematic. There’s also the question of the connection between monogamy and romantic, exclusivist love. For example, it has been found that monogamous prairie voles mate exclusively for life, with the first ready member of the opposite sex they encounter. Clearly this isn’t about romance or conscious decision-making. It will be argued that it is preposterous to compare humans with prairie voles, but from a biological perspective, perhaps not so much. We often talk of ‘love at first sight’ and ‘I don’t know what hit me’ (sometimes with regret). There is no doubt that this sort of immediate sexual attraction can largely be explained by biochemistry. Monogamy in general appears to involve an interplay of hormonal and cultural effects.

Dr Helen Fisher, an anthropologist and research fellow at the Kinsey Institute and Rutgers University, separates romantic love into three parts – lust, attraction and attachment. To summarise, doubtless too briefly, the hormonal effects here, the sex hormones testosterone and, to a lesser extent, oestrogen play a predominant role in increasing libido, or lustful sensations. The hypothalamus stimulates production of these hormones by the ovaries and testes. Testosterone, it should be emphasised, is not a ‘male’ hormone. It produces a variety of effects in both sexes. Attraction is a more complex, more conscious elaboration of lust. It may involve some weighing up of the costs and benefits of particular lustful feelings, though generally under the ‘sway’ of lust. The brain areas involved include the hippocampus, hypothalamus, and anterior cingulate cortex. The activation of these regions tend to increase trust in the object of lust and to inhibit defensive behaviour and anxiety. The hormones dopamine and norepinephrine (aka noradrenaline), which create a sense of euphoria, the sense of ‘being in love’, with its sleeplessness and obsessiveness, will have obviously differential effects depending on the object of attraction’s response to the person attracted. Feelings of attraction also appear to reduce serotonin levels, which help regulate appetite and mood.

Attachment, not surprisingly, is the most complex, conscious and culturally influenced of these three stages. It’s quite a bit cooler (temperature-wise) than the other two, and extends often to other connections, such as friends and family. The hormones most involved in this stage, or state, are vasopressin and oxytocin. Interestingly, those prairie voles mentioned earlier differ greatly from their promiscuous cousins, montane voles, in that they express far more of these two hormones. When these hormones are blocked by researchers, prairie voles turn promiscuous. It would of course be depressingly reductionist to describe attachment, and the other states, as well as their more negative features, such as jealousy, possessiveness and emotional dependence, in purely hormonal terms, but we need to understand, and so to positively change a world of human aggression and thuggery, so prominently displayed on the world stage today, to one a little more bonoboesque, while still preserving the best of our humanity – our inventiveness and our curiosity. Understanding how our hormones affect us is a good start.

References

https://www.ckn.org.au/content/cupid’s-chemical-addiction-–-science-love

Ferdinand Mount, The subversive family, 1981

Robert Sapolsky, Behave, 2017

https://journals.sagepub.com/doi/pdf/10.1177/0265407511431055