Why aren't men stupid? (Evolution)

[GenderRealistBloke]

Or rather: given the massive and ancient sex-specific selection pressures we evolved under, why have men and women turned out to be of basically the same intelligence?

Being intelligent has a cost, in terms of energy that can't be spent on other things. To oversimplify a bit, species only evolve features that really make a difference. Too much or too little of something tends to get evolved away.

My intuition is that being a woman required more intelligence than being a man, in the evolutionary environment (raising children and managing social relations seems a lot more complex than coordinating to hunt and fight). But whichever way your intuition runs on that, isn't it weird that it's turned out to be pretty much exactly the same?

Short answer, we're mammals. With very very few exceptions, mammals don't have huge differences in size and shape between the sexes (aside from genitals and secondary sex characteristics). There's a small difference in height between males and females in most mammal species, but thats it. No major differences between body plan aside from ones directly related to reproduction.

As a result, males and females of a species generally have similar sized brains. And its the size of the brain that uses energy, not the amount of intelligence in that brain.

So there's no evolutionary advantage to men being less intelligent. Our brains use the same amount of energy either way, and womens birth canals would still need to be the same size, as they'd have to push out female heads as well as male ones.

That wasn't dolphins that worked that out, it was the mice.

(Rereading Hitchhikers Guide at the moment!)

Intelligence varies a lot between humans though. Wouldn't your theory lead us to predict that wouldn't happen?

It’s generally understood that intelligence - if by intelligence we mean a broad spectrum of skills which include problem solving, critical thinking, nuance, inference, emotional relating, the ability to learn from experience, creativity - is influenced by a range of factors: genetic variation; environment in utero; environment in childhood; experiences and exposures; healthcare and nutrition; education and availability of learning resources. Our genetics may provide us with an intellectual capacity but our environment determines if we reach our potential.

(raising children and managing social relations seems a lot more complex than coordinating to hunt and fight)

If you believe that you will believe anything.

I expect some are, as are some women.

Genes?

Men and women may have the same or similar intelligence (subject to the usual distribution curve) but their attitude to risk, for evolutional reasons was, and still is vastly different. That affects how the intelligence plays out into action, or inaction.

Men and women may have the same or similar intelligence (subject to the usual distribution curve) but their attitude to risk, for evolutional reasons was, and still is vastly different. That affects how the intelligence plays out into action, or inaction.

Perhaps it's different re physical risk, but there was a study a few years ago which iirc assessed risk-taking in a work context. It turned out women's risk taking/aversion correlated with their menstrual cycles and wasn't necessarily overall lower than mens. (No idea what applies post menopause but many of us find we don't give a fuck what people think any more...)

It has been proven though, that the relative difference in the size of the human brain between different individuals has no bearing on their intelligence.

According to the book Sapiens, the thing that makes humans “intelligent” and separates us from other mammals is the ability to plan ahead, create strategies and to share ideas and imaginations. These can be applied in different areas of our lives. So the base level of intelligence should thereby be the same between the sexes. For example, planning and communicating a proposed hunt strategy with other men may use the same intelligence as planning and communicating a safe children’s play afternoon / food preparation / dwelling organisation with other women.

is that the sort of thing you mean, op?

Why do you think that?

Would you say it's the other way round, or would you say it's exactly the same? If exactly the same, where does that intuition come from?

Yes it is, though could you explain the "thereby" bit?

In other words, both sexes plan, but why should that mean equal?

Both sexes run, but that hasn't given us the same speed. Both need strength, but that hasn't given us the same strength. Both need to fight, but we don't have the same physical aggressiveness, etc. Because the trade-offs vs other things worked out differently.

Not stupid you say?

I see your Boris Johnson and raise you Liz Truss.

(Although both Oxford graduates).

@haddockfortea

I'm not sure that's true. The opening sentence of this large metastudy on humans is "Brain size and IQ are positively correlated." which is pretty unequivocal.

royalsocietypublishing.org/doi/10.1098/rsos.211621

Surely For there to serious differences between the sexes there would need to either be genes for intelligence (whatever that may be) on the sex (X,Y) chromosomes or an intelligence phenotype that was controlled/mediated by sex specific hormones.

Without that then the intelligence genes are being mixed up (one from mother one from father) when gametes join & that isn't dependent on the sex of the zygote.

And you have a great username for this discussion!

To oversimplify a bit, species only evolve features that really make a difference. Too much or too little of something tends to get evolved away

This isn’t strictly true. Sexual selection (as opposed to natural selection) can work almost in the opposite way as this, leading to the evolution of features in males that can actually end up being maladaptive. Think of the ridiculousness of a male peacock’s tail. It’s not enormous and shiny because it confers an advantage in terms of survival, but because the ladies like massive and shiny. And the argument is that they like massive and shiny because it signals that this guy is so good at competing for resources that he’s got all this excess energy that can be spent on something not particularly useful for his survival.*

I’m not convinced that make intelligence is primarily a product of sexual selection though. Intelligence and the language and tool-making that accompany it massively increase the fitness of both sexes.

*Disclaimer: Been a while since I studied evolutionary biology - this may not be an up to date or accurate explanation of sexual selection!

I'm excited to have an evolutionary biologist here! (Or at least someone who has studied it).

Is this something that is considered odd (or at least, requiring an explanation) in the field?

I know you said you don't think it's mainly sexual selection, but I suppose it could be like the peacock's tail: after all, a lot of human 'showing off' is intelligence related (including linguistic ability), and we do seem to spend a lot of time on cerebral things with no immediate practical advantage (many games, many people's advanced degrees, etc).

Definitely not an evolutionary biologist but I do remember it being absolutely fascinating.

Is what considered odd? Sexual selection? Not odd at all, the theory goes right back to Darwin. Sexual selection tends to create big (and highly visible) differences between the sexes though, so I’d assume the equal intelligence of men and women is a sign that it’s not highly sexually selected.

Yes, I find it fascinating too. I should read more of it!

I didn't mean sexual selection, but instead my question of why big intelligence disparities didn't evolve as a result of 'specialising' in different things.

From Google and ChatGPT there is lots on how intelligence differences in men and women may have evolved (meaning small differences in aptitudes for different things) but not in the big-picture similarity that puzzled me.

The reason they didn't intellectual disparities didn't evolve if because there was no selection pressure for them to.

I think you're misunderstanding how evolution works a bit. Evolution doesnt tend towards the best traits, it tends towards the traits that don't get us killed before we have a chance to procreate. (Hence why we've still got appendixes. Yeah, they like to kill us sometimes, but not frequently enough or always early enough for them to be a big enough negative to evolve away from having)

There's not really any negative for men being just as intelligent as women. You mention the calorie cost of intelligence, but this isn't really a thing. The calorie cost is based on the mass of the brain, not what we do with it.

And brain size has absolutely nothing to do with intelligence. Crows use tools, but are hugely smaller than albatrosses, which can't even recognise their own chick as a chick if it falls out of the nest. (Intelligence is actually much more about surface area, hence the folds in brains. Generally, the smarter the animal, the more wrinkly its brain. Take a look at a picture of a koala brain, an animal that can't even recognise a leaf as food if its fallen off the tree, it's the very definition of a "Smooth Brain")

So, what are the costs / benefits to intelligence?

Cost - Sometimes instinct wins out. When a lion is running towards you, sometimes freezing while you run all the options through your head isn't a good idea. A strong instinctual response to RUN! would be a much better option.

Benefit - Communication. Generally, the most intelligent animals are the ones who work together. Communication breeds cooperation, and cooperation breeds survival. If you can tell your kids that Dave died when he ate those berries, then your kids are less likely to eat them. You're far more likely to bring down a woolly mammoth if you can strategise with each other. Far more likely to be able to make tools if your parent passes down that knowledge to you. All of the most intelligent animals are ones who live in groups, who live in societies.

And on an individual level, evolution tends towards intelligence. You're far more likely to pass your genes on if you can remember not to eat the red berries, or stand under a tree when there's a thunderstorm, or if you don't get expelled from the tribe because for being a liability during the Woolly Mammoth hunt.

The only time evolution selects away from intelligence is if it can't afford it. Going back to the koalas - They've evolved to fill a very specific niche. They eat exclusively eucalyptus leaves, a food that almost no other animal will bother to eat because it lacks nutrition. This is great for koalas, because there's loads of food for them, but it means that the only calories they can afford to expend are on eating and sleeping. Every moment they're awake they eat, they can't afford to expend calories on anything else, including thinking. A koala that thinks, dies of starvation. So they've evolved to have smaller and smaller, smoother and smoother brains, to the point that they can't even do basic pattern recognition to work out whether this green eucalyptus leaf shaped thing on the ground is actually food.

Haven’t read the whole thread

Calorie cost is a red herring. Calories are needed for running fighting lifting etc just as much (if not more) as for intelligence

The main thing is head size. Humans have traded a high rate of neonatal and maternal death (compared with other animals) and slower child development for greater head and brain size. This is what distinguishes us.

We have no control over whether we gestate girls or boys. Therefore there is no evolutionary benefit in males having smaller heads/brains - the female anatomy has to be able to cope with larger head sizes and so boys may as well have the same large heads (& intelligence) as girls.

What you'd do as a god is the flaw in your arguement.

Hunting and fighting isn't about just being strong. It's about being quick witted, anticipating the next move and being three steps ahead. Tracking. Using weapons.

And child raising wouldn't have been that complex. The body would show them what to do during labour. High mortality rates when complications arise. Put screaming baby onto teat like animals do. Chemicals probably more helpful for instincts than actual IQ points. They have eaten what was available, ones that couldn't likely died. Know how to strip down an animal, direct, preserve meat and skins etc.

But none of that is clearly requiring more intelligence than a man.

Social relations aren't linked to IQ.

How are you measuring iq tho? If men and women were raised in identical ways with identical expectations, so you think the men would consistently underperform in any test of intelligence?

No not weird

Partly because I don't think intelligence relies much on the sex genes - it's other genes

It would cost you something to produce different brain types depending on sex

And because from early time - tool making was needed for hunting and for cooking for example - we did better a species because we found better ways to do all sorts of things