Tuesday, 5 May 2009

Maternal instincts

In a recent discussion about immunisation, the question was asked: does mum really know best?

I'm going to be upfront here - I don't believe there's any such thing as maternal instinct. I believe that many mums have a special relationship with our kids; but this is because we're often the primary caregivers and socialised to be interested in kids, not because of anything mystical ordained by nature. I've known people (both men and women) who've had affectionless upbringings, and who've had trouble expressing their love for their own kids. This is just one of the reasons I think that parenting is learned, not natural.

Because I spend a lot of time with my kids, I have some expertise. I know how they learn best, I know how to reason with them, and I can almost always tell when they're sick. I have another canny mothering ability, too, and I wonder if this has a biological basis: I can always hear my kids crying (more so when they were babies), when nobody else can.

But my expertise has limits. I was happy to take my midwife's advice to give my kids Vitamin K after birth, because she'd done the research and I hadn't. I don't know the best way to teach a child mathematics or science. I don't mind the so-called nanny state giving me suggestions on how to feed my kids healthily or how to discipline without smacking, so long as I'm being given the best information available. I'd never consider freebirthing, because my ability to bear children doesn't give me the medical expertise to deal with a potential medical problem. There are many limits to my knowledge, and maternal instinct simply doesn't tell you stuff like how to cope with childhood asthma or prepare a balanced meal.

I think it's tempting to buy into ideas about maternal instinct because they seem to recognise the specialness of our mothering work, in a society in which paid work matters more than unglamorous domestic labour. But if we subscribe to the idea that mother inherently knows best, we both downplay the parenting potential of men, while giving them an excuse not to pull their weight around the house. And that, ultimately, is self-defeating for women.

29 comments:

Giovanni Tiso said...

It seems to me that believing in a maternal instinct and believing that mother knows best are quite unrelated. Instincts may be natural but natural isn't always good or best.

If nothing else, we need medicine to integrate the body's natural ability to heal itself.

Anonymous said...

I totally believe in maternal instinct but not "Mother knows best". I don't see it as the same thing at all.

Trouble said...

Hah, must be something in the water: Pandagon on vaccination and mother knowing best

Lucy said...

If anything, I think that putting good parenting down to "instinct" makes it less valuable, because it downplays the immense amount of hard work involved in *learning* how to work with your kids. Let's face it; on an evolutionary level, "instinct" only needs to make sure you don't actually kill off your kids before puberty, through comission or omission. Culture and society are learned things; how we deal with our children is part of those, and equally learned.

It is probably true that the main caretaking parent learns to pick up on far more unspoken cues, which seems kind of magical, but really is no more so than the way people learn to read anyone they spend enough time with.

Anna said...

I think that part of the cultural myth around maternal instincts (and I don't mean that in a derogatory way) is that mums do have a special sort of knowledge. If we didn't believe this culturally, we wouldn't hold maternal instincts or intuition is such high regard - no one follows their instincts if they believe their instincts are wrong.

And this can lapse into dangerous stuff like Jenny McCarthy opposing vaccinations because she believes, as a mother, that they caused her children's autism. Usually, when someone comes out with an unsubstantiated theory, it doesn't really wash with the public. If someone does it in their capacity as a mother, it resonates differently.

Lucy - completely agree with you. I also think that if we regard parenting as a natural attribute, we may see no need to improve our own skills.

A Nonny Moose said...

Right on, great post.

Completely agree on instinct vs Mother Knows Best. This is an argument that gets me in such hot water sometimes. The societal expectation that mother is best for baby is completely unfair to the father, government and welfare systems trying to help out too.

In the case of the vaccination disussion, I REALLY don't understand the "I know what's best" shrill versus the wealth of knowledge and assistance from govt/medical. Anti-vaxxers say "where's the knowledge?", but it is there if you look in the right places - they only see what they want to see.

Anonymous said...

When I talk about maternal instincts I mean something at a much more basic level than "having a feeling" about choosing or declining a medical course of action. To me instincts are more on the level of the way it feels wrong to be out of sight of your infant for more than a few minutes or how (almost physically) painful it is to hear your baby cry and not be able to respond. It's primal early-days stuff for the most part.

jo said...

Don't quite get what you're trying to say here, every woman/person/parent is entitled to do things their way, as long as its not hurting anyone why should it bother you that some women/parents/people choose to rely more on instinct than others? Or that you don't and think we should all be just like you? Also not every parent/woman/person is in a nuclear family like you often assume.

Anna said...

No, what I'm saying is that what might seem like instinct isn't. For me, some things seem instinctive and natural - like having my baby sleeping in bed with me, picking up a baby when it cries rather than letting it cry itself to sleep, and not smacking. But some people do the opposite of all these things, and their way feels completely instinctive and natural to them. A woman with post-natal depression might feel that she lacks 'normal' maternal instincts of affection towards her child, when what's really happening is an illness beyond her control - in that situation, beliefs about what 'normal' women are instinctively like can add to the distress.

If certain ways of mothering were instinctive, you'd expect we'd all do them, but women have parented very differently throughout time and across different cultures. There are plenty of examples, particularly in colonisation situations, where indigenous child-rearing practices have been deemed abnormal because they don't match with the practices that seem instinctively normal to colonising cultures. This is not to say that every parenting practice is as good as every other, but if we put them down to instinct (something essential which can't be changed), then we have no reason to scrutinise our parenting to try to improve it.

I don't particularly care whether people rely on what they think of as instinct or not, within certain boundaries of course (a person might be 'instinctively' tempted to shake a crying baby, but that's clearly not a thing that should be condoned).

The idea of instinct is potentially pretty essentialist, and can have nasty connotations for that reason. It's been argued many times throughout history that women are by nature too weak/irrational/whatever to participate in various areas, from the workforce to the political arena.

And as I mention in the post, but arguing that women are instinctively fit for parenting, you imply that men are less fit for it. I've heard men say, and believe it, that women are better suited to caring for children than they are. That's corollary of that argument is clearly that most or all childcare work should be done by women, not shared. You also imply that women know how to parent by virtue of having given birth - and that completely denies the struggle and confusion that mums can have, especially with their first baby.

jo said...

arguing that women are instinctively fit for parenting, you imply that men are less fit for it. I've heard men say, and believe it, that women are better suited to caring for children than they are...i don't think anyone was applying this at all. It seemed to me that you were trying to find a one-size-fits-all and this isn't possible with either parenting or being a woman. I appreciate that you clarified what you were saying.

Giovanni Tiso said...

arguing that women are instinctively fit for parenting, you imply that men are less fit for it. I've heard men say, and believe it, that women are better suited to caring for children than they are.

It doesn't strike me as unreasonable, it's what we do with the information that counts. Evolutionarily speaking, we're stuck in the thundra, hunting and gathering. The males of the species are bigger, can throw spears farther, etc. The females of the species are smaller, equipped to give birth and nurse children (bearing in mind in those days you't tend to have few kids and nurse them until they were about five). It's entirely reasonable to propose, as evolutionary psychologists do, that our minds would have similarly evolved around those basic tasks - men fitter for hunting, with the attendant skills that it requires, women fitter for the social transmission of knowledge and the care of the family. There's your instinct, if you want to call it that, and I think anybody who's being around children knows of their vastly different inclinations at a very young age, which some time resemble that horrid book about what boys and girls can do that was linked to last week.

The problem as I see it is that none of this allows us to say anything interesting about the present. We don't live in the thundra anymore. We no longer hunt. The social transmission of knowledge has become ever more important. Nurturing requires very different skills. And furthermore, we have rightly developed a gender politics that argues that we shouldn't force men and women into primate roles just because we might in fact be differently equipped. We tell girls they can be explorers, boys that they can be stay at home dads, and so forth. They each can do what the other can, much as they will likely bring a somewhat different genetic makeup and set of skills to the task. But none of those makeups and skills constitute a claim to the *right* way of doing something.

Anna said...

Evolutionary psych gives me the heebee jeebies (sp?). Because it's based on survival of the fittest, there's an implicit qualitative judgement that the status quo is good, because it represents the pinnacle of evolution thus far. Plus evolutionary psychologists like to come up with contradictory or untestable hypotheses. One sociobiologist I read argued that women have an inherent drive to breed, but those who don't want to breed have simply adapted to their environment in an evolutionary way. So two opposite scenarios both provide support for the same hypothesis. Hmmm.

This same guy also rebutted the accusation that evolutionary psych offers justification for men's sexual violence and aggression. He argued that the prevalence of particular behaviour across a population doesn't mean the individuals which make up that population are more likely to so behave - even though it clearly does mean exactly that. He then added that the best thing we can do is teach our young men to recognise that they will have the urge to commit sexual or other violence, and that they need to control this. I'm personally not comfortable positing all men as potential rapists - besides which, there is absolutely no way you can argue that without offering a mitigating factor for these crimes.

Giovanni Tiso said...
This comment has been removed by the author.
Giovanni Tiso said...

Because it's based on survival of the fittest, there's an implicit qualitative judgement that the status quo is good, because it represents the pinnacle of evolution thus far.

There really is no such thing, although a whole lot of people who are uncomfortable with evolution and with science more generally make that *explicit* claim all the time. And besides, even a supposedly implicit claim of that nature would say nothing of the validity of the theory, in the same way that the fallacy of social Darwinism does not invalidate the theory of evolution itself.

This same guy also rebutted the accusation that evolutionary psych offers justification for men's sexual violence and aggression.

I would hope so. Observing and explaining (which is what evolutionary psychology and science in general tries to do) has got nothing whatsoever to do with justifying.

He argued that the prevalence of particular behaviour across a population doesn't mean the individuals which make up that population are more likely to so behave - even though it clearly does mean exactly that. He then added that the best thing we can do is teach our young men to recognise that they will have the urge to commit sexual or other violence, and that they need to control this. I'm personally not comfortable positing all men as potential rapists - besides which, there is absolutely no way you can argue that without offering a mitigating factor for these crimes.

Mmmhh... there are more men than women in prison. A lot more. This is true at every latitude, so it must have something to do with men being comparatively more likely to commit acts that fall afoul of the laws that organised societies have created. By the same token, though, these laws were created mostly by men, and yet they are the same laws that incarcerate males in greater numbers. In other words: societies have always known that men are more prone to violent acts than women, it’s not an idea that evolutionary psychologists have had to come up with. But they’ve also never considered it a mitigating factor in the eye of the law. The obvious (and significant) exceptions are rape and the so called crimes of passion. But there too the forces that historically have pressed to depenalise or mitigate the crimes have been religions, and there are few things that major religions abhor more than the theory of evolution.

Again, it’s a case of recognising that instictual and natural don’t equal good. There is of course a far greater predisposition for rape in men, statistically speaking, it's impossible to deny since it crosses all cultural barriers. It doesn't mean that every man is a potential rapist, or that women don't rape, and it in no way it follows that rape should be depenalised. If you know that there is such a predisposition, on the other hand, you can address it, with education and such like.

Anonymous said...

As a man, I am entirely comfortable with the idea with telling men that they have a predisposition towards violence, particularly sexual violence. As Giovanni says a predisposition towards something doesn't represent a justificaton for doing it. Telling men that they are not more likely to rape than women is not only a lie, it's a dangerous lie. The fact is a man does need to monitor his actions more than a woman, and attempting to tell him he doesn't can have dangerous results. Once again, I say this as a man.

Anonymous said...

I am so sick of hearing this ritualistic 'women can rape too'. Sure, it may be true in a very limited, technical sense, but it is so incredibly rare that I don't see why it needs to be discussed, particularly in the context of a discussion of male rape. It's just an attempt to divert the issue and really needs to be seen as such. Appending a discussion of male rape with 'but women rape too' is about as meaningful appending it with 'pohutakawa trees blossom in summer'

Anna said...

Tony Veitch just argued provocation as his excuse for breaking a woman's back. A good chunk of the public had sympathy with this, and judging by his sentence, the judge did the same. I've never yet heard of a woman successfully using provocation as a defence against violence - because we believe that what is somehow understandable and natural when done by a man is not when done by a woman. Last week, a woman was sentenced for setting fire to her ex-boyfriend's empty house. She tried to put out the fire after starting it, and was remorseful afterwards. She got two years in prison.

My father once sat on a jury at a murder trial - a man shot his wife point blank in their home because she'd made a snide remark about his sexual prowess. He was found guilty of murder, not manslaughter, because ten minutes passed between the remark and the shooting. Less time, though, and the jury felt the man would have had himself a mitigating factor - what ordinary red-blooded bloke can be expected to restrain himself from violence immediately after a snide remark, after all?

If those aren't examples of assumptions about nature providing justifications for violence, I don't know what is. 'She led him on' continues to be a defence in rape cases. I grow very, very weary of bullshit excuses for some men's lack of self control and disrespect for women.

Until we live in a culture which stops condoning male violence, we're not going to have a control group to test any feeble sociobiological hypotheses against. But until sociobiology puts forward even one idea that can't readily be explained by social factors, that won't matter too much.

PS Giovanni, your comment about people disagreeing with evolutionary psychology because they're afraid of science is incredibly patronising. Richard Lewontin and Stephen Jay Gould have both criticised sociobiology and evolutionary psychology. As esteemed scientists, I'm guessing they're quite 'comfortable' with science.

Giovanni Tiso said...

Giovanni, your comment about people disagreeing with evolutionary psychology because they're afraid of science is incredibly patronising. Richard Lewontin and Stephen Jay Gould have both criticised sociobiology and evolutionary psychology. As esteemed scientists, I'm guessing they're quite 'comfortable' with science.

Not sure about what Lewontin’s gripes, but I can assure you that Stephen Jay Gould’s had absolutely nothing to do with the idea that ‘there's an implicit qualitative judgement that the status quo is good’, which was the object of my criticism as you recall. His objection was that evolutionary psychologists insist too much on adaptation vs other modes of evolutionary causation. I’m not saying that evolutionary psychology cannot be criticised, I have reservations about it in my own humble self. But it should be criticised for what it says and does, not for the ways that others misinterpret it, sometimes very willfully indeed. It really is exactly the same bogus relationship as there is between Darwin’s theories and social Darwinism.

If those aren't examples of assumptions about nature providing justifications for violence, I don't know what is.

And all your examples have anything to do with evolutionary psychology how exactly? Do you think that Veitch’s apologists are all Stephen Pinker or Dawkins’ enthusiasts? Of course they aren’t. You seem to have this idea that evolutionary psychology is part of the culture that condones male violence, but it isn’t. One of the many things it does is to partly *explain* male violence. They’re two entirely different things. Condoning is a choice that society makes, and that in relation to the violence that men inflict on women (as opposed to other men) it has made for many centuries if not millennia before Darwin and co.

AWicken said...

Giovanni: "In other words: societies have always known that men are more prone to violent acts than women, [...] But they’ve also never considered it a mitigating factor in the eye of the law."

Not quite true - duelling was leniently treated (if restricted at all) in most western societies well into the 19C, and that's pretty much the definition of social-status based male evolutionary violence. Also, in the USA until the mid/late 20C they actually had a legal defence of "fighting words" - i.e. a chap uses words so inflammatory that a resulting assault is a reasonable expectation, and therefore the fight is HIS fault, not the guy who throws the first punch.

Similarly, the notoriety of some female criminals/generals (and the social sanction when their actions weren't legally justified) - based on a few minutes quick reflection by someone with a reasonable knowledge of general history, but no special expertise in this particular area - seems to be a bit larger their male colleagues. I would suggest that this is because the greater social expectation for males to be violent to some degree mitigates the male's actions than the female's(or makes the female's actions more abnormal and worthy of greater social/legal sanction, which amounts to the same result).

Giovanni Tiso said...

Not quite true - duelling was leniently treated (if restricted at all) in most western societies well into the 19C, and that's pretty much the definition of social-status based male evolutionary violence. Also, in the USA until the mid/late 20C they actually had a legal defence of "fighting words" - i.e. a chap uses words so inflammatory that a resulting assault is a reasonable expectation, and therefore the fight is HIS fault, not the guy who throws the first punch.

Not sure if I agree on dueling being a sanctioning of evolutionary violence, I think it was more a way of preventing escalating feuds by giving injured parties the opportunity to remedy (real or perceived) offences before we came up with libel laws and the civil code. A damage reduction exercise if you will, based on a pragmatic recognition that things could get a lot worse.

But fair enough on the 'fighting words' front. And besides the situation where women have been found at fault for being assaulted, there is of course sanctioned class violence, where you could strike a subordinate or a slave.

I'm curious though as to whether evolutionary psychologists are sometimes tarred with this ridicolous notion that they're condoning male violence simply because they bother to talk about it in the first place. After all, is there anybody who thinks that men aren't in fact more prone to violence on average than women, or who believe that it's everything to do with nurture and nothing to do with nature?

Anna said...

I'm not suggesting that Lewontin or Gould are putting forward the same criticism as me - just that opposition to evolutionary pschology doesn't necessarily stem from fear of science. Nor am I suggesting that evolutionary psychologists condone violence - they clearly don't. The reading I've done in this area (not huge, admittedly) was quite clear that they don't. The authors I've read just believed that men have a natural predisposition towards violence, which society has a responsibility to control. You can't put that argument forward without providing a mitigating factor for said violence.

The sociobiological/evolutionary psychology stuff I've read seemed like a caricature of Darwinism to me, used selectively to justify particular social practices, while skirting around the illogical conclusions of its own arguments.

I've heard it argued that women live long after their childbearing years because evolution has equipped them for grandparenting duties. This is dumb on so many levels that it's hard to know where to begin. It suggests that parenting arrangements are the same across all cultures, and I'd be surprised if anthropological evidence supports this - in fact, I'd think that grandparents playing an active role in their grandchildren's lives has become more common with medical advances that have increased longevity and quality of life. If mothers were unable to parent without the assistance of grandparents, it wouldn't bode well for the species. It suggests that whatever help is passed from the grandmother to daughter is actually social learning, or you'd expect the mother to already 'know' it by virtue of her evolutionary heritage - there's not much evolutionary sense in acquiring your own parenting skills long after having children. And one wonders why nature lets impotent old men live after their reproductive capacities have dwindled - so they can play golf? This looks to me like psuedo-science which appeals to people's commonly-held beliefs about gender. And this shite just reinforced the kind of thinking that results in sympathy for Tony Veitch, but a jail sentence for a female fire-bug. There's a market for 'science' which confirms people's prejudices.

What possibly irks me even more is that some sociobiological arguments implicitly draw on an un-nuanced notion of selection (eg females are attracted to 'strong' men who will protect them and supply them with healthy offspring, as much today as 10,000 years ago), and then draw on the idea that selection favours variation in a species to explain the nonsensical consequences of the first argument - ie some women don't exhibit dependent behaviour because they've adapted to a social context in which women are able to be independent of men. And then you're right back to the elastic hypothesis that can't be tested.

Anyway, must go ... have an overwhelming urge to breed.

Giovanni Tiso said...

I will leave your other straw arguments well alone, they indicate only that you’ve read very superficially and selectively on this subject. As a matter of passing interest, Pinker’s How the Mind Works debunks much of the tripe you attribute to evolutionary psychology, but is in fact simply a lazy pop version of it. I have even less time to waste on it than he does.

(Also, I guess that Pinker's The Blank Slate ought to be mentioned in a thread that talks about instinct. Hell, pretty much anything he's written really.)

This interests me though:

The authors I've read just believed that men have a natural predisposition towards violence, which society has a responsibility to control. You can't put that argument forward without providing a mitigating factor for said violence.

I take it you don’t believe that men have by nature a greater predisposition towards violence than women. Correct?

Anna said...

Giovanni, I'm not really interested in debating with you if you can't make your point courteously. And you shouldn't feel obliged to read or comment if you feel your time is being wasted.

You might prefer to read the peer-reviewed journal 'Evolutionary Psychology' instead. In the most recent edition, the article 'Testing the Cuckoldry Risk Hypothesis of Partner Sexual Coercion in Community and Forensic Samples' concludes that 'cuckoldry risk influences male sexual coercion in established sexual relationships'.

Giovanni Tiso said...

I'll be as curteous as you like. Again, trying to explain the adaptive emergence of certain behaviour does not justify the behaviour. So, without having read the piece, the cuckold theory does not make me quake in my pro-feminist boots, much as the selfish gene idea advanced by Dawkins doesn't threaten my ideas regarding altruism and solidarity.

You still haven't answered the question that would make all of this discussion moot, anyway. If you don't think that men are naturally more inclined to be violent than women, but rather it's entirely dependent on the way that we are socialised (in all cultures, in all times leading up to the present), then so be it. But if you do in fact think that there is such a natural propensity, then you're justifying male violence in exactly the same way as an evolutionary psychologist.

In fact, most people believe in innate fundamental differences between the sexes. The thing that distingueshes evolutionary pscyhologists is that they attempt to explain how these differences (and other stuff) might have come about by reverse-engeneering evolution. Sometimes they say interesting things that make intuitive sense or are testable and proven true, sometimes they say things that sound ludicrous or a little far-fetched to my ear, but overall it's a pretty compelling theory and I thank them for it.

On a side note, I may not be a feminist but I'd like to think that I'm a socialist. A lot of people consider innatism inimical to socialism, but my rational mind tells me that if there's truth in it, then it ought to be explored and understood. It won't invalidate my politics, I'll keep believing that societies can be made more just and progressive, simply because I have seen it happen in history.

Anna said...

I don't believe in human nature, so I don't believe in natural instincts (except at the basic, reflexive level - ie someone throws an object at you, and your hindbrain makes you duck before you consciously decide to act).

Whatever generalisation you make about human behaviour, there's an anthropologist with evidence to contradict it - and I don't see much reason to assume that similar patterns of social organisation should be found across different cultures, given the differences in technology, social institutions, resources, ability to trade, etc between cultures. Even incest hasn't been universally prohibited across cultures.

I once read a sociobiological analysis of some particular mating behaviour of hummingbirds. It was interesting and plausible. What wasn't plausible was the attempt to extrapolate insights into human behaviour from birds bonking. I'm no hummingbird expert, but they don't seem to have the ability to be introspective, understand causation to any great degree, anticipate the future or comprehend the motivations of others of their species the way humans can. Given that, for centuries, the social structures of many societies have militated against humans giving in to evolutionary impulses (ie rape, except for marital rape, has been a punishable offense), you'd expect some sort of adaptation to a changed social context (and the adaptation argument is made often, including in the article I quoted). Given the capacity of humans to adapt, it's hard to imagine why evolutionary impulses would survive, or what purpose they'd serve if they did.

The article I referred to before doesn't even include sociocultural factors which might contribute to violence in its regression analysis - in fact, it doesn't even mention these factors, leaping to the least likely conclusion instead. Amongst other things, it says:

'There is some evidence supporting the idea that partner sexual coercion is a response to cuckoldry risk. Shields and Hanneke (1983) found that 47% of women who were beaten and raped by their husband reported having had sex with another man, whereas only 23% of those beaten but not raped and 10% of nonvictimized wives admitted to engaging in such behavior'.

Another gem is 'we hypothesized that domestic assault functions as “coercive control” to prevent female infidelity'. The unqualified comment that female infidelity affects men's breeding fitness is also disturbing.

The use of the word 'cuckoldry' (which I've noticed a few times in writing of this sort) attaches moral connotations to the female behaviour being studied, yet the neutral phrases 'sexual coercion' and 'sexual coaxing' are used to describe rape. That doesn't bear on the validity or otherwise of the hypothesis, but it says ominous things about the underlying assumptions of the study. The men studied are discussed as if they are automatons, in terms of predictive factors and risk.

I don't look at this journal often, but the article I'm quoting isn't out of the ordinary. It actually makes me feel ill.

Giovanni Tiso said...

I don't believe in human nature, so I don't believe in natural instincts.

Well, that's good enough for me - I'll give you credit for the coherence of your position, but couldn't debate it any more than I can debate a person of faith.

For everybody else, The Clean Slate really is a cracking read.

AWicken said...

Actually, Giovanni, given what I see on the street on a Saturday night, I would say that women are just as prone as men to violence - at least the street-level stuff, anyway.

There are a number of situations where male violence is culturally more expected, but women seem to slap people and throw bottles at people just as often as men do. Their excuses are also as worthless (my personal favourite being the woman who felt she couldn't be done for an assault because she aimed the bottle at an ex down the street, not the guy it actually hit).

Just because males commit more violence does not mean it's psychological "wiring" - as far as I can see it's just "that was the style at the time".

Giovanni Tiso said...

Actually, Giovanni, given what I see on the street on a Saturday night, I would say that women are just as prone as men to violence.

Wow, the criminal justice system must be really stacked against males then.

AWicken said...

No - there are just more situations where males think violence is "acceptable" (and, of course, the individuals in the justice system feel it is appropriate to respond). This isn't the result of evolutionary imperative - it's cultural practise.


A quick (well- dialup) look at Statistics NZ table-builders also seems to show an increasing proportion of female violent offenders being apprehended - national stats for the last 10 years show that less than 1 in 6 apprehended offenders for violent offences were female, whereas this was just under 1 in 5 in 2008.

Variations in cultural practices can explain variations in the gender proportions of activities, including violent crime, within the space of a decade, but it's difficult to use evolution to explain such a generationally quick variation.