The mind is certainly a very mysterious organ, I reflected,.. about which nothing whatever is known, though we depend upon it so completely.
Virginia Woolf, A room of one’s own, 1928
ah yes, it all makes sense now…
So there’s still plenty to learn about the mind, and maybe calling it the brain is only giving us a false sense of the matter (and I’m thinking of ye olde ‘what’s mind, it doesn’t matter, what’s matter, never mind’ jibe), though we’ve made great neurophysiological strides in recent decades. But having just read Virginia Woolf’s thoughts on the position of women almost a century ago, and being old enough to remember texts like ‘Women are from Venus, men are from Mars’, which sought to ‘explain’ and make the best of the pigeonholes the author presumably believed in, I’ve decided to have another quick look at the current expert views on the neurophysiological and hormonal differences between the sexes.
What I’ve found is that it’s still a contested issue. When I last reported on it, I found myself very happy to accept that there are statistical differences between male and female brains, but no categorical differences. That’s to say, both male and female brains vary widely, and it’s reasonable to say that the differences within each gender are as great as the differences between them. Another striking way to think about it is to say that, were you to hand a still living but completely disembodied human brain (just imagine!) to a trained and experienced neurologist, they’d be unable to say categorically that it was M or F.
Well, the first website I’ve come to disputes this claim. It’s from PNAS (often fondly vocalised as ‘penis’, which may or may not be relevant) and it’s a short essay with only one author, Marek Glezerman. My initial sense of it is that he misses the point, and seems disturbingly emphatic. To give an obvious example, the title of the piece is “Yes, there is a female and a male brain: Morphology versus functionality”. In his opening paragraph (but the essay only has two paragraphs), Glezerman summarises the conclusion he disagrees with, a conclusion I based my own essay on years ago:
The authors conclude that brains of women and men are not dimorphic and not categorically different, as are the genital systems of the two genders, but resemble more an overlapping mosaic of specific functional regions and therefore cannot be distinguished as male and female brains.
Reading this made me wonder, and I thought back to the night before – ahhh, the night before – when I spent time at a well-frequented pub full of individuals, male and female, well beyond the first flush of youth. It occurred to me that there wasn’t a single person there whose sex I would feel mistaken about. Many of the men, and none of the women, were balding, bearded and paunchy. Some did have breasts, I admit, that could’ve competed with the females, but I doubt if they’d have managed the same expression, so to speak. And though there was a lot of variety in the voices, it was easy enough to distinguish males from females in that characteristic. Of course there were also differences in dress, mannerisms and choice of drink, but those could be put down to ‘culture’ and dismissed. Even so there might be enough evidence on display to suggest a categorical difference – a morphological difference – traceable to the brain and hormones.
So, what did Glezerman mean, exactly, by ‘morphology versus functionality’? Well, here’s a long, but essential quote from his essay.
Whenever the terms “female brain” and “male brain” are used, the intention should be functional and not morphological, qualitative and not quantitative. Functionally, brains of women and men are indeed different. Not better, not worse, neither more nor less sophisticated, just different. The very brain cells differ chromosomally. The male brain is exposed to a completely different hormonal environment during intrauterine life than the female brain. The available scientific data as to the crucial effect of testosterone on the developing male brain is overwhelming.
Glezerman provides references for his claim about testosterone and its effects, a subject of great interest to me, but I’ll leave that for another essay. But one wonders if this isn’t a storm in a teacup. Going back to my pub reference, of course there were differences within the sexes – some males seemed more ‘feminine’ than others, whatever that may mean, and some women more ‘masculine’. This may again be a matter of hormone expression rather than personal choice, or a complex combination. I find it fascinating that male hormone levels (i.e testosterone) are dropping in the WEIRD world, a matter of concern to some, but not me…. oh, but that’s for that other essay, or did I already write that one?
PNAS has a reply to Glezerman’s essay, which I’ll now focus on. And I should note how polite and civilised these scientific disputes are: far from the world of social media. This response is even shorter that Glezerman’s little essay (I’ll bet that was by design!), so I’ll reflect on it here, passage by passage.
As Marek Glezerman (1) rightly points out, there are differences between females and males in brain and behavior. Glezerman overlooks, however, the fact that such differences may be different and even opposite under different environmental conditions. That is, what is typical under some conditions in a brain composed of cells with an XX chromosomal complement residing in a body with low levels of testosterone, may be typical under other conditions in a brain composed of cells with an XY chromosomal complement residing in a body with high levels of testosterone.
Being a person who spreads himself thinly over a wide variety of intellectual topics (i.e master of none), I had to look up XX and XY (remember mate, two kisses female, one kiss male – which is surely typical). What the response (which has three authors) appears to be saying is that what is typical for a low-testosterone female in some conditions, may also be typical for a high-testosterone male under quite different conditions, in spite of the fact that one set of brain cells carries an XY chromosomal complement, while the other carries XX. Not sure if this carries the day though. But to continue:
Such “reversals” of sex effects have also been reported when the manipulation of environmental conditions was done in utero (by manipulating the dam) and the offspring were tested in adulthood (reviewed in refs. 2 and 3). These observations led to the hypothesis that brains are composed of a “mosaic” of “male” and “female” features rather than of only “male” features or only “female” features, as expected of a “male brain” and a “female brain,” respectively (2, 3)
Wasn’t sure what ‘manipulating the dam’ meant, but a dam is a dam, something that reduces or stops flow, so I suppose this was done in non-human test species? Presumably if you’re able to change hormonal conditions in utero via such methods – or by changing environmental/social conditions, as bonobos appear to have done – you will change the mosaic of behaviour. Bonobos can be quite aggressive, but it appears to be more tilted towards the male of the species. Also, the drop in male testosterone is surely due to changed conditions and expectations for males over a relatively short period – for example in the mere century since A room of one’s own was written, but even more so in the past few decades of mechanisation and anti-machismo, at least in the WEIRD world.
Our study (4) is the first to empirically test whether brains are “male” or “female” by assessing internal consistency in the degree of “maleness-femaleness” of different elements within a single brain. We found that brains with both “female-end” and “male-end” characteristics were more prevalent than brains with only “female-end” or only “male-end” characteristics. This was true for both the volume of brain regions and the strength of connections between regions (assessed in a similar way to ref. 5), in contrast to Glezerman’s assumption that “Other imaging methods might have yielded different results.”
This is claiming evidence for mosaic traits in a majority of the brains under study, both for individual regions in isolation and for brain connectivity. All I can say is that this seems eminently plausible, indeed I would’ve expected such a finding. Not sure, of course, what ‘male-end’ and ‘female-end’ characteristics are exactly. There is a question here, though, about what Glezerman meant by ‘other imaging methods’.
To corroborate our analysis of different aspects of brain structure assessed using MRI, we also analyzed brain function, as revealed in people’s behaviors, personality characteristics, preferences, and attitudes. Also here there were many more people with both “feminine” (i.e., more common in females compared with males) and “masculine” (i.e., more common in males compared with females) characteristics than people with only feminine or only masculine characteristics (4).
Behaviour, over time, can affect brain function and brain regions mightily. An obvious case is language, spoken and written, which is a behaviour that has had considerably impact on the brain, as, for example Maryanne Wolf recounts in Proust and the squid. You’d hardly expect those brain regions that have been adapted/co-opted for language production/reception to have been much affected by gender. The same would go for other skills and practices, such as mathematics. As to the different physical characteristics of males and females (my pub observations), how connected are they to our brains? They certainly have much to do with hormones, of which we have at least fifty types, many of which are connected to/stimulated into action by the pituitary gland, which is in turn stimulated by the hypothalamus, but these regions account for a minuscule proportion of the brain.
There is no doubt that sex affects the structure and function of brain cells. However, the fact that sex can affect brain cells does not necessarily entail that the form and function of brain cells are either “male” or “female” nor that the brains comprised of these cells can be divided into two distinct categories. For such claims to be true it is necessary that the effects of sex are dimorphic, resulting in the formation of distinct “male” and “female” types, as well as internally consistent (2, 3, 6).
I think what’s being said here is that just because our brain cells, indeed all our somatic cells, have either an XX or XY chromosomal complement in their nuclei, this doesn’t dictate essential expressed traits – our intelligence, our humour, our physical skills, our bodily needs, and so forth. As this essay suggests, ‘manipulating the dam’ in utero is likely to have a far greater effect on human development than gender does, unless of course you’re born into a culture in which one gender is significantly undervalued. But let’s not go too near that hornet’s nest.
So to the last lines of the reply to Glezerman:
Hopefully, future studies looking at the relations between sex and other systems in which sex differences have been documented (e.g., the immune system, the cardiovascular system) will assess both internal consistency and degree of overlap, to reveal whether the relations between sex and other systems are more similar to the relations between sex and the brain (mosaicism) or to the relations between sex and the genitalia (dimorphism).
And no doubt there will be differences, especially in relation to hormonal levels associated with the reproductive system, but also in those associated with diabetes, the heart and the circulatory system and so forth, but these are not easily predictable based solely on gender. And there’s another problem with fixating on sex differences in a hard and fast way. It’s not exactly coincidental that male supremacists are all for favouring such differences. That’s why the bonobo example needs to be known and promoted far more than is currently the case.
Canto: So we haven’t focussed on bonobos for a while – I’d love to be able to answer the question, How did bonobos become female dominant?
Jacinta: Yes, were they always that way? That would mean, presumably, that they were female dominant at the time of their split from chimpanzees, somewhere between one and two million years ago (a rather vague time-frame, for me), which would then raise the question – how did chimps become male-dominant?
Canto: Haha, a question we don’t ask ourselves, we’re so used to being male-dominant. I seem to recall that one reason, or theory, is that bonobos have evolved in a region that’s densely vegetated, plenty of fruit and nuts, not so much hunting as gathering, which doesn’t require so much physical strength and aggression.
Jacinta: Which is interesting – we humans are evolving, at least in the WEIRD world into a post-industrial species, where manual labour is being replaced by mechanisation, robotics and such, requiring less of the physical strength of old-fashioned factory work. Australia, for example has become, internally, a service economy, exporting raw materials such as iron ore and coal, and importing finished products. There are few labour-intensive jobs these days, and testosterone levels are dropping, happily.
Canto: Yes, if we can take the long view – a very difficult thing for humans – we can see that only a couple of centuries ago women couldn’t get a decent education, couldn’t participate in government or be workplace bosses – though there were always the rare exceptions – but now the gates are opened and the trickle to the top is happening. In a thousand years or so – not so long in evolutionary time – we might have achieved a bonobo-style humanity.
Jacinta: Well on that sort of happy note, let’s see if research has told us anything about bonobo femdom. The quickest click-research brings up this, from the Max Planck Institute:
Some researchers suggest that bonobo female dominance is facilitated by females forming coalitions which suppress male aggression. Others think of an evolutionary scenario in which females prefer non-aggressive males which renders male aggressiveness to a non-adaptive trait.
That’s from ten years ago, and I doubt if we’ve gone much beyond those very reasonable speculations, with both of those developments, female coalitions and less aggressive males, creating a synergistic effect.
Canto: Well, looking more closely at that fairly short article, they suggest that female attractiveness – by which they don’t mean looking like Taylor Swift or FKA Twigs, but displaying sexual receptivity through behaviour or sexual swellings, seems to soften up the males somehow:
If females display sexually attractive attributes, including sexual swellings, they win conflicts with males more easily, with the males behaving in a less aggressive way.
Which is the opposite of male chimp behaviour, so why, and when, the difference?
Jacinta: Well, the article mentions two changes – subtle differences, no doubt, in female sexuality and in male mating strategies over a million or two years. And, okay, that doesn’t tell us anything much. As to when, obviously these are changes that developed gradually. Emory University, in Atlanta Georgia, which has done a whole-genome comparison of chimps and bonobos, makes a more specific claim for the divergence:
Chimpanzees and bonobos are sister species that diverged around 1.8 million years ago as the Congo River formed a geographic boundary and they evolved in separate environments.
Canto: But is it likely that genomic comparisons will tell us much about these subtle – or, ok, not so subtle, differences in behaviour? I mean, comparing the genes of Taliban Afghans and Aussie radical lesbians isn’t going to tell us much, is it? It seems to me to be largely a cultural shift.
Jacinta: Well, the Emory website, I must say, has the most interesting little article I’ve found for a while, and it relates to diet, which we’ve looked at before, and hormone production, which we haven’t, because it’s a bit sciencey for us dilettantes. Let me quote at length from the site, as I think this will provide us with a sense of direction for our own future research, if you can call it that:
The whole genome comparison showed selection in bonobos for genes related to the production of pancreatic amylase — an enzyme that breaks down starch. Previous research has shown that human populations that began consuming more grains with the rise of agriculture show an increase in copies of a closely related gene that codes for amylase.
“Our results add to the evidence that diet and the available resources had a definite impact on bonobo evolution,” Kovalaskas says. “We can see it in the genome.”
Compared to chimpanzees, bonobos also showed differences in genetic pathways well-known to be related to social behaviors of animals — as well as humans. Bonobos had strong selection for genes in the oxytocin receptor pathway, which plays a role in promoting social bonds; serotonin, involved in modulating aggression; and gonadotropin, known to affect sexual behavior.
“The strong female bonds among bonobos, in part, may be mediated by their same-sex sexual behaviors,” says co-author James Rilling, professor and chair of Emory’s Department of Anthropology. “Our data suggest that something interesting is going on in the bonobo pathways for oxytocin, serotonin and gonadotropin and that future research into the physiological mechanisms underlying behavioral differences between bonobos and chimpanzees may want to target those specific systems.”
Canto: Yes, that’s a most interesting finding, and one to follow up – pathways for serotonin, oxytocin and gonadotrophin, think SOG. And think not testosterone. And of course it’s not about opening up these pathways artificially, with, I don’t know, hormone supplements and such, but engaging in and encouraging behaviour that takes us along those pathways….
Jacinta: Haha I think oxytocin comes first, even if it wrecks the acronym. Looks like we need a crash course in endocrinology.
Canto: Or a crash course in how to raise our levels of, or expression of, those hormones? Over the next million years or so? With lots of orgasm-inducing touchy-feelies?
Jacinta: Well I can’t see that happening for as long as we have anti-sex religions dominating many nations. I seem to remember there were a few ‘free love’ cults back in the hippy days, but things have dulled down since then. You’d think there’d be a return, what with the mechanisation of labour, and the growth of the service economy. What better service can we offer our fellows than body rubs? Mind you, the Japanese seem to be leading the way there – a notably non-religious people. And yet, still far too patriarchal….
Canto: Interesting that Japanese teams have led the way in bonobo studies. Let’s hope they’re spreading the news among their countrywomen.
Jacinta: Well the sex video industry in Japan, and its sex industry generally, is enormous, though doubtless very exploitative. I presume it’s being driven by men rather than women – not exactly the bonobo way. A country that forces its few female politicians to wear high heels is far from being female-dominant. At least that was the case in 2019, when there was a backlash against this grotesque policy. I presume it has changed, but it isn’t clear.
Canto: Well, this has been interesting. We need to look more at endocrinology and happiness, or at least pleasure-inducing practices, in future… meanwhile, Vive les bonobos!
not sure if this measures a significant difference
Canto: So, as it turns out, the bonobo-oxytocin connection is all the rage on the internet. I mean, there are at least two articles on it. Here’s a quote from a PubMed article called ‘Divergent effects of oxytocin on eye contact in bonobos and chimpanzees’:
Previous studies have shown that bonobos and chimpanzees, humans’ two closest relatives, demonstrate considerable behavioral differences, including that bonobos look more at others’ eyes than chimpanzees. Oxytocin is known to increase attention to another’s eyes in many mammalian species (e.g. dogs, monkeys, and humans), yet this effect has not been tested in any nonhuman great ape species.
Jacinta: Hmm, so how do they know this? Presumably they’ve dosed subjects with oxytocin and measured their eye contact against controls?
Canto: No no, they know that bonobos have more eye contact than chimps, simply from observation. So they might infer from this that bonobos produce more oxytocin naturally than chimps…
Jacinta: So do women produce more oxytocin than men I wonder? I presume women make more eye contact than men.
Canto: Well in this study they dosed both bonobos and chimps with oxytocin, and the effect – more eye contact – was greater in bonobos than chimps. In fact, chimps even tended to avoid eye contact when shown images of conspecifics.
Jacinta: So, it’s a matter of interplay between this hormone/neurotransmitter and social conditioning?
Canto: Maybe, but you’d think that an increase in this supposedly touchy-feely hormone would act against social conditioning. Isn’t this the point of that drug, ecstacy? That it reduces social inhibitions… But presumably nothing is ever so simple. Being poor, I only have access to the abstract of this paper, but another abstract, which looks at the effects of oxytocin and vasopressin on chimps, describes them as neuropeptides, just to confuse matters. The abstract also refers to about a dozen brain regions, as well as specific oxytocin and vasopressin receptors, so it gets pretty complicated.
Jacinta: Okay, vasopressin… from Wikipedia:
Human vasopressin, also called antidiuretic hormone (ADH), arginine vasopressin (AVP), or argipressin, is a hormone synthesised from the AVP gene as a peptide prohormone in neurons in the hypothalamus, and is converted to AVP. It then travels down the axon terminating in the posterior pituitary, and is released from vesicles into the circulation in response to extracellular hypertonicity (hyperosmolality). AVP has two major functions… etc etc
Canto: Okay thanks for that, let’s stick with oxytocin for now. It’s produced in the hypothalamus, a smallish region buried deep within the brain, just below the larger thalamus and above the even smaller amygdala. It releases and manages a variety of hormones. Brain signals are sent to the hypothalamus, exciting it to release oxytocin and other hormones, which are secreted into the bloodstream by the posterior pituitary gland….
Jacinta: Can you tell me what oxytocin is actually made of? Its structure? The term ‘hormone’ is just a black box to me.
Canto: Okay, here’s a diagram of oxytocin to try and make sense of:
It’s a polypeptide. A peptide is basically an amino acid chain. FYI:
An amino acid is an organic molecule that is made up of a basic amino group (−NH2), an acidic carboxyl group (−COOH), and an organic R group (or side chain) that is unique to each amino acid. The term amino acid is short for α-amino [alpha-amino] carboxylic acid.
Jacinta: So these are coded for, ultimately, by genes?
Canto: Yes, we’re heading backwards here, but each amino acid is encoded by a sequence of three of the four base pairs in our DNA. Anyway oxytocin, among other things is sometimes given to women while in labour. It helps with the contractions apparently. I’ve also heard that the recreational drug ‘ecstasy’, or MDMA, works essentially by releasing oxytocin.
Jacinta: It just so happens I’ve found an interesting 2014 paper published in Neuropsychopharmacology, my new favourite journal, called ‘Effects of MDMA and Intranasal Oxytocin on Social and Emotional Processing’, and here’s a quote from the abstract:
Oxytocin produced small but significant increases in feelings of sociability and enhanced recognition of sad facial expressions. Additionally, responses to oxytocin were related to responses to MDMA with subjects on two subjective measures of sociability. Thus, MDMA increased euphoria and feelings of sociability, perhaps by reducing sensitivity to subtle signs of negative emotions in others. The present findings provide only limited support for the idea that oxytocin produces the prosocial effects of MDMA.
Canto: That is interesting. If that finding can be replicated, I’d say forget the MDMA, dose people with oxytocin. A small but significant increase in feelings of sociability might just be enough to transform our human world.
Jacinta: Hmmm. Small but significant – that sounds a mite contradictory.
Canto: Not the same as significantly small. That slightly significant dose, administered to Messrs Pudding and Pingpong and their enablers, might’ve saved the lives of many Ukrainians, Uyghurs and advocates of multiculturalism, democracy, feminism and other wild and woolly notions. And it doesn’t really transform characters, it just softens their edges.
Jacinta: Yes it’s a nice fantasy – more productive than butchering the butchers, a fantasy I occasionally indulge in. But not workable really.
Canto: Why not? We dosed petrol with lead, and look at how that worked out. It certainly had an effect. In Japan they still use radium baths (at very low levels) for health purposes, even claiming it as a cure for cancer. I’m not sure if oxytocin baths can ever be a thing, but if so I’m sure there will be early adopters.
Jacinta: Well, it’s good to think positively. Oxytocin is often thought of as a bonding hormone between mother and child. The key would be to ensure it facilitates a more general bonding: to cause Mr Pingpong, for example, to see Uyghur, Tibetan, Yi, Limi, and all the other non-Han ethnicities in China as his sisters – or lovers even, revolting as that would be to those peoples.
Canto: Better than being their oppressors and exterminators.
Jacinta: Slightly. But I wonder, quite seriously, if, assuming such a dose of bonding could be effectuated, we could still function as the sometimes rational, problem-solving, highly creative species we indubitably are. Would there be a price to pay for all that oxytocin? And how would this affect all those other hormones and neurotransmitters and all their myriad effects? Humans are notorious for causing extra problems with their solutions, e.g lead, DDT, etc etc.
Canto: Well, there’s no need to worry about the fallout from this solution as yet. I just googled Putin and oxytocin together and came up empty. Obviously we’re way ahead of the curve.
Jacinta: Haha, it’s not a curve these days, it’s a pivot. Get with the program!
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.
