Are male and female gender roles a relic from our evolutionary past?

[Missymoo100]

Ok, so here's a theory;
Sexual dimorphism is an evolutionary trait not found in every species.
In humans, man evolved to be stronger and faster. Natural selection gave him the advantage in hunting, protecting the family and competing with other males for access to resources and to females.
Women evolved to bear and nurture children, they would have been vulnerable at times due to pregnancy and in need of support/protection.
Whilst feminism seeks to redress the differences between men and women in today's world- could ideas about gender role exist because they were once useful and not stem simply from misogyny?

On the whole we tend not to be polygamists though so I think our size disparity is largely done to our hopeless offspring who need to be gestated and then breast feed for ages. Probably about 3 years in the wild! All at the cost of a huge number of calories.

If you look at birds where they only have to lay an egg before the male can help out then the males and females often look quite similar sizes.

if there were no difference in gender roles at any time why did sexual dimorphism occur- i.e. Men became more muscular, usually larger, faster etc

Well, sexual selection is one reason. Women chose to mate with men that were bigger, faster etc. and hence these traits proliferated. Of course, the men that women chose to mate with were not necessarily the same men that women lived with, raised children with, etc. Even in monogamous societies, infidelity is common.

And don't forget that sexually selected traits do not have to confer any survival advantage to the individual. Take the peacock's giant tail: it exists because it catches the fancy of peahens, but doesn't help him secure more food or live longer (and is actually a bit of a liability for the peacock dragging it behind him as he tries to escape a predator).

Similarly, human males' greater height, shoulder breadth and muscle mass doesn't necessarily confer a survival advantage to the individual. These traits may exist simply because they have caught the fancy of women over time, but don't really help them secure more food (most nutrition in hunter-gatherer societies comes from gathering fruit, veg and small game, not bringing down big animals). These traits might help an individual man live longer if faced with a large predator, but humans are apex predators in most environments so that isn't very likely. It might help a man live longer if he is fighting other men, but that comes down to mate competition again: if women didn't find bigger/faster bodies attractive, men wouldn't be using power and speed to compete (and would grow big feathery tails instead). Indeed, since larger bodies come with increased energy requirements, it's also the case that men's increased height, shoulder breadth, and muscle mass is a bit of liability for survival during times of privation.

In many sexually dimorphic species, the males are flashier to attract the interest of the females. There's no good reason to ignore that explanation for humans.

'Women chose to mate with men that were bigger, faster etc. and hence these traits proliferated.'

But many of these traits didn't proliferate. Early hominids were less dimorphic than their ancestors and we are less dimorphic than early hominids. They've been selected against, not for.

If females had selected the biggest, strongest and most muscular, men would now look similar to silverback gorillas.

So basically we've been seeing it through the patriarchal "dominant male" viewpoint.

Exactly, it's like we're looking through the wrong end of a telescope - we see one male and 20 females and believe he's keeping himself a harem of laydees for sexy fun time. But actually it's a community of females keeping themselves a solitary pet male for sexy fun time.

Its not just lions and primates that live in these types of herds - lots of herbivore animals, like antelope do. Like quentin says, most males are cast into the wilderness, they live in little bachelor groups whilst the females live in women and children herds with just one male. The females don't even treat the males like a king because they're grazers not hunters, they all just grab their own food on the move.

But I'm not sure how it fits in with the practice of infanticide where the new alpha male kills the existing babies as he enters.

He isn't an alpha. He's been sent across as a present from another commune or traded as necessary. He doesn't have to kill the babies in the commune - not least because he's only one man and the women wouldn't let him, but because adult males would never be kept in their own tribe to avoid inbreeding, it isn't the babies in this commune that are a threat - its the foreign ones. The only aggression would be from the outgoing male, kicking and screaming as he's cast out.

baboons keep females in one place and send their boys out to find a new group - though they do have alpha and beta males, the new incoming boys try to claw their way to the top of their new pack but they don't kill the existing babies.
There was a really interesting long term study done, though, where a tribe was followed for years and then disaster struck, a nearby restaurant threw out a load of rancid meat. The alpha's ate it all, not sharing with the rest of the tribe, and they all died! But rather than the betas turning alpha, the females and beta males started working co-operatively and lived much happier and stress free lives. Any incoming males either had to accept this new societal set up or they were chased off.

So its possible that even in nature gender roles only exist as long as they're useful or a hierarchy can be maintained. As soon as something changes they'll be jettisoned. so there's nothing 'innate' about any of it.

You ought to read "the decent of woman" think it's by Elaine Morgan .

If females had selected the biggest, strongest and most muscular, men would now look similar to silverback gorillas

That would be hilarious! or possibly terrifying.

I think when people think about stone age people selecting a mate, they tend to look at what animals do and forget that stone age people are - well - people . You don't fall in love with the biggest, the strongest, the best hunter, the one with the best resources etc etc. You fall in love with who you fall in love with. And it's far more likely that women were falling in love and pair bonding with the men who were working closely alongside them gathering, hunting small game, working in the camp than they were with the hero warrior alpha hunters who were off hunting for a week at a time.

Plus the men who stayed with the women would have far greater opportunity to breed, even if love as we recognise it wasn't a factor.

I think it has more to do with the lesser natural selection of humans combined with our intelligence. Humans are the only mammal who are knowingly cruel just for the sheer hell of it, rather than to fulfil a purpose. So I don't think it's impossible it wasn't just because male humans realised sheer muscle made it possible.

For any species with predators or natural selection still playing a large part, it would be phenomenally stupid. Eg if a stallion had decided the mare was no longer running the herd, and he'd be in charge, and he'd use his bulk to enforce that, he'd soon lose his herd to injury, predators, weak stock etc. Whereas for humans that hasn't been a problem for a very long time.

I agree that women being a commodity is partly why too. Capture your neighbouring tribe and the men are a physical threat, whereas the women aren't and can be used.

The peacock scenario can be explained by zahavis handicap theory- the tail is a burden but signals to a female the male has managed to survive despite this , meaning his other genes are good. However upper body strength would be advantageous.
Interestingly chimps, our closest ancestor, are another species that are deliberately cruel, they will rip smaller monkey limb from limb while the group cheers on with excitement.

Chimps aren't our ancestors. The pan and homo genii evolved from a common ancestor not one from the other.

Meant to say relative, we share at least 97%+ of our DNA with them.
Killer whales are another species deliberately cruel- it's not a trait exclusive to humans

If females had selected the biggest, strongest and most muscular, men would now look similar to silverback gorillas.

Only if sexual selection was the only selection force in operation. It's certainly not - there are many more factors at play in trait selection in humans.

The point is that the male-centric "man the hunter" account of sexual dimorphism is as good (or bad, tbh) as the female-centric "woman the sculptor" account. They both present simplistic explanations of single drivers for complex sets of inter-related traits The evidence base is similar for both, but only one keeps being pushed endlessly by those who want to rationalise their biases.

Sexual dimorphism and traits connected to physical aggression in males have consistently reduced in hominid species.

Whatever the drivers were for sexual dimorphism, they had an impact on something ancestral to hominids, not hominids themselves.

So nothing that can be legitimately be called a woman or a man, nothing that used stone tools, or could start a fire, or cook, or make a spear, was ever selected for greater or static sexual dimorphism.

The driver on hominids was for sexual dimorphism to reduce, for males and females to be more similar.

missy but they don't have our intelligence, or the same ability to empathise so it isn't knowing, calculated cruelty. Just like a well fed domestic cat that isn't teaching kittens to hunt or refining it's own skills can be unintentionally cruel, or a toddler who thoughtlessly pulls a dogs tail until an adult explains. Other mammals do not go through the full thought process, with full knowledge of how it will feel to the victim.

Sexual dimorphism and traits connected to physical aggression in males have consistently reduced in hominid species.

Well, not consistently. That used to be the consensus but it was based on pretty sparse data (and suboptimal modelling) in some cases. Now, the evidence points towards very Australopithecus afarensis being only moderately sexually dimorphic, at a similar level to modern humans.

So if pre-Homo species were only moderately dimorphic, then later Homo species more more strongly dimorphic before returning to moderate dimorphism in modern Homo, it suggests sexual dimorphism waxed and waned as selective pressures varied rather than monotonically reducing over time.

But anyway. It just means that there aren't good empirical grounds to claim that the drivers were for sexual dimorphism had no impact on hominids themselves. That door is still open.

Chimpanzees are fairly intelligent though and do show alltruistic behaviour, along with some very dark behaviours, like killing and mutilating their own kind.. especially subordinate males. Humans developed morality due to higher level of thinking.

www.bbc.co.uk/earth/story/20150811-do-animals-fight-wars

Humans may well be cursed with "a demonic male temperament", says Wrangham. But "we are also blessed with an intelligence that can, through the acquisition of wisdom, draw us away from the five-million-year stain of our ape past."
"Even if we did inherit a propensity for violence, it's not the only thing we inherited," says Stephen Pinker of Harvard University. "We have self-control, empathy, reason and cognition, we have moral norms."

The article suggests that violence may be innate behaviour to our species but we have the power of self control

I don't doubt their intelligence, and I don't think humans are the only species who can have complex behaviours. But I still think that a chimp or any other animal being needlessly cruel isn't capable of reasoning why they shouldn't, any more than a human toddler knows without learning it. And unlike the toddler they don't have a duty to learn it themselves as their brains develop.

I think even morality isn't that straight cut. I think it's society, as well as thinking skills that allow it. Look at the cases of cannabilism during famine, even relatively recently. Higher level thinking will prevent the vast majority of humans eating their neighbours kids because meat is a bit sparse, unlike many carnivores, but when it gets to the point of your young eating or dying, all that higher level thinking and morality would be eclipsed by instinct.

It's only because we mostly live in societies where we aren't reduced to that and even in those that are dying of starvation it isn't always practical that we can live by that morality.

Lurkedforever

I agree with you. I do think some behaviours are evolved, but as humans we are able to know right from wrong whereas other primates wouldn't recognise this. I think behaviours which are needless today may have served purpose in earlier ancestors/man.
Relating this back to gender roles- if males exhibit different behaviours and have different body morphology to females, then would this have not made sense for them to take on different roles, each having its own advantages?

Agree with Rita that's a great article, pretzels.

I was pondering yesterday, while watching some birds going through a bizarre mating ritual, why almost every species has bright attractive males and drab females other than humans, where women are expected (in the Western world) to dress up, wear makeup, make an effort and men are not.

Olennaswimple-
Generally females are choosier because pregnancy and infant rearing is more costly in terms of energy and resource investment. Males have unlimited reproductive potential- millions of sperm, the only limiting factor is finding females who will mate with them- therefore they tend to try and look more impressive- by for example, evolution of more colourful plumage in birds or mating displays, penguins try to impress females by bringing them a nice pebble. I don't know why human females try to impress males, although I suppose customs like an engagement ring is similar to the penguin with his pebble

No man has ever brought me a nice pebble

missy yes, but if you look at mammals the female gender role isn't either inferior or viewed as inferior to the males role from a herd PoV. And the females role is often superior and/or includes aspects of the males role too. And in some the male also does the female role.

olenna I wonder if it's partly because historically women were vulnerable in society if they couldn't attract a mate? And for a better mate, you'd also want to prove you could provide heirs which would mean a display to show you're young and beautiful.