Hard-wired behaviours in human males and females?

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Hard-wired behaviours in human males and females?

#1  Postby Reeve » Dec 16, 2012 2:28 pm

Looking at this as a biologist, should we expect to find that there are biologically hard-wired differences in behaviour between human males and females?

I've wondered whether there might be a bit of a double standard with humans when it comes to us considering this. In modern society it seems that people have no problem acknowledging that in other species of animal: "the male of the species does X" while "the female of the species does Y." Yet when it actually comes to humans (those almost chimpanzee creatures :grin: ) I think there's a bit of an aversion to the idea that the males and the females' behaviour might be pre-set to differ in fundamental ways. This is why the field of evolutionary psychology is hated in some circles, for example.

I'm not promoting that there are any such difference in behaviour or what those differences might be; I'm asking whether we should expect to find that there is.

My opinion is that we should expect to see that there is. We find it lots of other closely related organisms, so I think it would be quite a surprise if we didn't find it in humans.

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Re: Hard-wired behaviours in human males and females?

#3  Postby Macdoc » Dec 16, 2012 3:46 pm

No question there are differences and lots of documentation - not sure why this is significant enough for a post here. :scratch:

Hell the elbow joints are different for one as well as hips.
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Re: Hard-wired behaviours in human males and females?

#4  Postby Reeve » Dec 16, 2012 6:56 pm

I mean specifically behaviour.
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Re: Hard-wired behaviours in human males and females?

#5  Postby tuco » Dec 16, 2012 7:14 pm

Hard-wired as in hmm observable in every wo/man behavior? How about hard-wired behaviors of humans, the so-called human nature, does it exist?
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Re: Hard-wired behaviours in human males and females?

#6  Postby Thommo » Dec 16, 2012 7:17 pm

Reeve wrote:I've wondered whether there might be a bit of a double standard with humans when it comes to us considering this. In modern society it seems that people have no problem acknowledging that in other species of animal: "the male of the species does X" while "the female of the species does Y." Yet when it actually comes to humans (those almost chimpanzee creatures :grin: ) I think there's a bit of an aversion to the idea that the males and the females' behaviour might be pre-set to differ in fundamental ways.


I don't see the double standard, people in general seem to acknowledge that men and women do dress and behave differently, the questions are whether they should behave differently and whether those behaviours are "hard-wired". Do we know that all differential behaviours in animal are "hard-wired"? What does it mean to be "hard-wired"?
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Re: Hard-wired behaviours in human males and females?

#7  Postby tuco » Dec 16, 2012 7:18 pm

Maybe hard-wired by some code ;)
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Re: Hard-wired behaviours in human males and females?

#8  Postby Macdoc » Dec 16, 2012 10:20 pm

Look to toddlers for differences. There are a number of neat experiments that highlight the differences.

Here is one

http://www.lifeslittlemysteries.com/280 ... rucks.html

and some more formal stuff

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3030576/
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Re: Hard-wired behaviours in human males and females?

#9  Postby Mr.Samsa » Dec 17, 2012 11:52 pm

Reeve wrote:I've wondered whether there might be a bit of a double standard with humans when it comes to us considering this. In modern society it seems that people have no problem acknowledging that in other species of animal: "the male of the species does X" while "the female of the species does Y." Yet when it actually comes to humans (those almost chimpanzee creatures :grin: ) I think there's a bit of an aversion to the idea that the males and the females' behaviour might be pre-set to differ in fundamental ways. This is why the field of evolutionary psychology is hated in some circles, for example.


It's not a double-standard, it's simply a reflection of the evidence. Studying evolutionary behaviors in any organism is difficult, but it's much simpler in animals where you can control (to some degree) their genetic makeup and control practically every aspect of their environment and history. With humans, you can't exactly get certain men and women to breed with each other, then take their babies away, raise them for years in isolation, and see what behaviors pop up. Also, keep in mind that when you're watching nature documentaries and they say things like, "The male of the species will now perform behavior X...", they are not necessarily making a claim about a hard-wired behavior - they are simply stating that it's a common or even universal behavior. Universal behaviors aren't necessarily innate, hard-wired, or evolutionary, and they can come about through a number of processes but this distinction is not important for the purposes of the documentary so they usually won't discuss it.

It would be nice if evo psych was hated because of political reasons but this has never really been true, in my experience at least. The overwhelming complaint with evo psych is that they rely on dodgy assumptions and perform shitty research. Part of the problem is the fact that there are constraints on the field as I discuss above, but part of the problem is that the researchers in the area often lack any education in evolutionary biology (and some even seem to lack knowledge of basic psychology, which confuses me as to how they manage to get into a field that combines the two). As such, you often find dodgy studies trying to prove that there are sex differences because boys and girls choose to play with different kinds of toys, ignoring the fact that these children have had years of training telling them which toys they should and should not play with.

It's certainly possible that there are hard-wired differences in men and women, but we're still a long way off from discovering them. We're still struggling to identify any evolved behaviors in humans, nevermind looking in more detail at sex discrepancies. And, most likely, if/when these differences are discovered, they won't be fantastical and impressive complex behaviors, instead they will be fairly general and mundane statistical differences in various cognitive tasks.

Macdoc wrote:Look to toddlers for differences. There are a number of neat experiments that highlight the differences.

Here is one

http://www.lifeslittlemysteries.com/280 ... rucks.html

and some more formal stuff

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3030576/


I think Reeve is looking for differences that are the result of evolutionary processes (hence the mention of "hard-wired" and "evolutionary psychology", etc). The paper you've linked to explicitly states that the results have nothing to do with determining whether the behavior is hard-wired or not.
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Re: Hard-wired behaviours in human males and females?

#10  Postby Reeve » Dec 20, 2012 5:08 am

Mr.Samsa wrote:
I think Reeve is looking for differences that are the result of evolutionary processes (hence the mention of "hard-wired" and "evolutionary psychology", etc).


:nod:

Although, taking the step back from asking "What are they?"; first of all: Should we expect to find them?
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Re: Hard-wired behaviours in human males and females?

#11  Postby Mr.Samsa » Dec 20, 2012 5:40 am

Reeve wrote:Although, taking the step back from asking "What are they?"; first of all: Should we expect to find them?


Hard to say for sure. It's possible that there are no differences at all and there's no reason to expect that there will definitely be differences, so I don't think we should expect to find them.
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Re: Hard-wired behaviours in human males and females?

#12  Postby Reeve » Dec 20, 2012 10:26 pm

Do you know if there are any clear cut cases found in mammals where there are any hard-wired behaviours? :ask:
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Re: Hard-wired behaviours in human males and females?

#13  Postby VazScep » Dec 20, 2012 11:12 pm

Mr.Samsa wrote:With humans, you can't exactly get certain men and women to breed with each other, then take their babies away, raise them for years in isolation, and see what behaviors pop up.
It's political correctness gone mad.
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Re: Hard-wired behaviours in human males and females?

#14  Postby Oldskeptic » Dec 21, 2012 1:27 am

Reeve wrote:Do you know if there are any clear cut cases found in mammals where there are any hard-wired behaviours? :ask:


It would be absurd to think not. The only other explanation for some behaviours would be teaching/learning. Mating behaviour and rearing young would be my first example. You don't find female mountain sheep butting heads for the chance to breed. Or female elephant seals fighting it out over who gets to be with the most powerful male. Were they taught this behaviour? One passive and the other aggressive? In my opinion it is highly unlikely. So how did it get there?

If anyone disagrees we can go on to talk about elephants, lions, and bears. And don't forget beavers pantomiming building beaver dams in captivity.

Lastly this hostility towards evolutionary psychology amazes me. It is a new field, and there have been some claims that do not hold up under scrutiny, but to deny that evolution has nothing to do with psychology and can't help explain is again absurd.
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Re: Hard-wired behaviours in human males and females?

#15  Postby Mr.Samsa » Dec 21, 2012 1:39 am

Reeve wrote:Do you know if there are any clear cut cases found in mammals where there are any hard-wired behaviours? :ask:


Yes, I'm sure there are many cases. I can't think of any specific examples off the top of my head, but I think many mating dances are gender-specific. It's important to be careful with some assumed examples though, like individuals butting heads or fighting for mating rights as learning often plays a huge role in these examples (for example, mountain goats practicing butting heads as kids, and then using it when they're older to fight for resources - no hard-wiring needed).

VazScep wrote:
Mr.Samsa wrote:With humans, you can't exactly get certain men and women to breed with each other, then take their babies away, raise them for years in isolation, and see what behaviors pop up.
It's political correctness gone mad.


:lol: It is! Those people must just hate science or something.

Oldskeptic wrote:Lastly this hostility towards evolutionary psychology amazes me. It is a new field, and there have been some claims that do not hold up under scrutiny, but to deny that evolution has nothing to do with psychology and can't help explain is again absurd.


A lot of the hostility towards evo psych is justified. It has nothing to do with denying that evolution affects psychology, it has to do with the current major approach to evolutionary psychology - that is, the approach taken by people like Buss, Cosmides, Tooby, Pinker, etc, is little better than pure pseudoscience. It's founded on baseless assumptions like adaptationism, environment of evolutionary adaptedness, and massive modularity, and generally has a lack of rigorous testing of hypotheses (for example, finding a culturally universal behavior and stopping the research there, instead of testing whether the universal behavior was learnt or evolved).

There's a good article on the topic here: [Evolutionary Psychology and the Challenge of Adaptive Explanation](http://ldc.upenn.edu/myl/GrayEP.pdf). Importantly, this doesn't mean that all of evolutionary psychology is nonsense, it just means that the kind of evolutionary psychology that people are aware of is nonsense. A good rule of thumb I find is that if it makes a claim about humans (especially if the claim is more grandiose than a mundane statistical discrepancy), then it's likely bullshit. Not because humans are special, but because the science is nowhere near being able to make claims like that (and potentially never will be).
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Re: Hard-wired behaviours in human males and females?

#16  Postby Beatsong » Dec 21, 2012 11:55 pm

Mr.Samsa wrote:
Reeve wrote:Although, taking the step back from asking "What are they?"; first of all: Should we expect to find them?


Hard to say for sure. It's possible that there are no differences at all and there's no reason to expect that there will definitely be differences, so I don't think we should expect to find them.


Of course we should expect to find them.

The fact that there are similar, clear and consistent differences between the behaviours of the sexes in those other species most related to us - without any influence of culture - is the first clue. We then basically have two ways of accounting for the differences between human males and females:

1. Just like chimpanzees etc, we have evolved different behavioural patterns for males and females, connected with their different physiology, reproductive nature etc.

OR:

2. All of those other species evolved such different behaviours, but at the point that our evolution split off from theirs, we miraculously reversed all that and quickly re-evolved men and women to behave largely the same way instead. Even more miraculous, however, we then invented culturally imposed norms of behaviour and designed them especially to LOOK as if they were evolved ones like those other species had!

It's pretty obvious which side Occam is shaving on here.

Secondly, there is considerable difference between many of the physical traits of human males and females, and in some cases these are even mutually exclusive differences of type (having testicles, or ovaries, or a womb etc.). The brain is a highly complex central control centre that has to interact with all of the various organs and processes in the body. If those organs and processes have evolved, over millions of years, to be different, does it not stand to reason that the brain will have evolved differently in the way it interacts with them? Whatever happens in the brain when a woman has a period, or goes through menopause - how does that relate to the male brain? Why would the brain, of all organs, remain resolutely the same in both sexes when it is having to do different jobs for each? That just doesn't make any sense. And indeed, these differences are what neuroscience is now starting to illuminate.

The idea that behaviour can be completely separated from physiology is ridiculous, so if there are different physiologies, there will be differences of behaviour. We know for example that behaviour is influenced by hormones - witness PMT, puberty and menopause. We also know that human males and females have a very different hormonal makeup from each other. Do the math.

Recent studies have found, for example, that girl babies born with congenital adrenal hyperplasia (who produce excessive androgen hormones) produce behaviour more like that traditionally considered "typically male", than like that of other girls. And this continues even after their hormone levels have been normalised - ie the effect of the particular hormonal balance on the developing brain is permanent.
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Re: Hard-wired behaviours in human males and females?

#17  Postby Beatsong » Dec 22, 2012 12:05 am

Mr.Samsa wrote:
Reeve wrote:Do you know if there are any clear cut cases found in mammals where there are any hard-wired behaviours? :ask:


Yes, I'm sure there are many cases. I can't think of any specific examples off the top of my head, but I think many mating dances are gender-specific. It's important to be careful with some assumed examples though, like individuals butting heads or fighting for mating rights as learning often plays a huge role in these examples (for example, mountain goats practicing butting heads as kids, and then using it when they're older to fight for resources - no hard-wiring needed).


And the fact that these kinds of behaviours are pretty much universally seen in the males of mammal species rather than the females, is just a co-incidence of learning? Like, one day a male happened to do it, and ever since then all the males in every subsequent generation have learnt to do it from their dads, while it's never occurred to any females to do it? And this just happened to be the case in every species where aggressive sexual rivalry is observed?
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Re: Hard-wired behaviours in human males and females?

#18  Postby Mr.Samsa » Dec 22, 2012 9:11 am

Beatsong wrote:
Mr.Samsa wrote:
Reeve wrote:Although, taking the step back from asking "What are they?"; first of all: Should we expect to find them?


Hard to say for sure. It's possible that there are no differences at all and there's no reason to expect that there will definitely be differences, so I don't think we should expect to find them.


Of course we should expect to find them.

The fact that there are similar, clear and consistent differences between the behaviours of the sexes in those other species most related to us - without any influence of culture - is the first clue.


But the point I was making was that there is no necessary reason for us to think that we should expect to find them. There are good reasons to suspect that there may be differences, like you mention, but I don't think this justifies a strong claim like "we should expect to find them".

Beatsong wrote:We then basically have two ways of accounting for the differences between human males and females:

1. Just like chimpanzees etc, we have evolved different behavioural patterns for males and females, connected with their different physiology, reproductive nature etc.

OR:

2. All of those other species evolved such different behaviours, but at the point that our evolution split off from theirs, we miraculously reversed all that and quickly re-evolved men and women to behave largely the same way instead. Even more miraculous, however, we then invented culturally imposed norms of behaviour and designed them especially to LOOK as if they were evolved ones like those other species had!

It's pretty obvious which side Occam is shaving on here.


Occam's razor doesn't work that way. You have to present the evidence first and find which explanation accounts for the most data with the least amount of assumptions - we don't simply look at the answer which is the simplest. Importantly, there are huge and significant differences in the physiological and psychological development of humans compared to chimps, so using the same pseudo-Occam's principle, we could equally say that it is unreasonable to assume that similarities in other species will translate to humans. We have to avoid falling into the same trap that dog trainers often make in assuming that because dogs are descended from wolves then they must share many behavioral similarities, when of course they actually share very little.

The point is not that there are no differences, but all I'm saying is that we need evidence before even bringing up Occam.

(And, to avoid being pedantic, I'll skip over the fact that Occam's razor has nothing to say on which explanation is right or not).

Beatsong wrote:Secondly, there is considerable difference between many of the physical traits of human males and females, and in some cases these are even mutually exclusive differences of type (having testicles, or ovaries, or a womb etc.). The brain is a highly complex central control centre that has to interact with all of the various organs and processes in the body. If those organs and processes have evolved, over millions of years, to be different, does it not stand to reason that the brain will have evolved differently in the way it interacts with them? Whatever happens in the brain when a woman has a period, or goes through menopause - how does that relate to the male brain? Why would the brain, of all organs, remain resolutely the same in both sexes when it is having to do different jobs for each? That just doesn't make any sense. And indeed, these differences are what neuroscience is now starting to illuminate.


Sure, we can certainly argue that the brains of men and women could have evolved differently to deal with different issues. The problematic part is the assumption that differences in the physiology of the brain will result in differences in behavioral patterns.

Beatsong wrote:The idea that behaviour can be completely separated from physiology is ridiculous, so if there are different physiologies, there will be differences of behaviour. We know for example that behaviour is influenced by hormones - witness PMT, puberty and menopause. We also know that human males and females have a very different hormonal makeup from each other. Do the math.


It's not ridiculous at all. Knowing that there are different physiological effects in different sexes gives us reason to suspect that there are differences in brain physiology, and differences in brain physiology gives us reason to suspect that there are differences in behavior, but this isn't a deductive argument and one does not necessarily lead to the other. It would be premature and unscientific to assume that we should expect to see behavioral differences due to differences in brain physiology.

Beatsong wrote:Recent studies have found, for example, that girl babies born with congenital adrenal hyperplasia (who produce excessive androgen hormones) produce behaviour more like that traditionally considered "typically male", than like that of other girls. And this continues even after their hormone levels have been normalised - ie the effect of the particular hormonal balance on the developing brain is permanent.


And that's interesting but it would essentially work against the point you're making. If men and women have evolved different brains due to the differences in levels of hormones and other brain chemicals, then flooding a "female brain" with "male chemicals" would tell us nothing about how a "male brain" is affected by or processes "male chemicals".

For us to make an inference from these results, you'd have to drop your claim that the brain has evolved differently in men and women in response to these chemicals, and argue that they have the same brain which develops differently based on the chemicals it receives. That's a plausible argument but: a) it's a much weaker claim, and b) we still need empirical evidence of actual differences between men and women which are innate rather than learnt.

Beatsong wrote:
Mr.Samsa wrote:Yes, I'm sure there are many cases. I can't think of any specific examples off the top of my head, but I think many mating dances are gender-specific. It's important to be careful with some assumed examples though, like individuals butting heads or fighting for mating rights as learning often plays a huge role in these examples (for example, mountain goats practicing butting heads as kids, and then using it when they're older to fight for resources - no hard-wiring needed).


And the fact that these kinds of behaviours are pretty much universally seen in the males of mammal species rather than the females, is just a co-incidence of learning? Like, one day a male happened to do it, and ever since then all the males in every subsequent generation have learnt to do it from their dads, while it's never occurred to any females to do it? And this just happened to be the case in every species where aggressive sexual rivalry is observed?


You are presenting a very narrow form of learning there. Learning is not limited to explicit learning (i.e. teaching) or observational learning (seeing another individual perform the behavior). It also comes about through the natural interaction with its environment. When you have organisms with the same basic traits and they're placed in the same basic environment, then it is inevitable that they will perform some behaviors which are exactly the same purely as a result of environmental factors. For example, a popular example when teaching this topic of species-specific constraints producing universal behaviors is the fact that all people, of all cultures, of all times, have always eaten hot liquids from a curved container (e.g. bowl or cup) rather than something flat like a plate. Is this because there are innate predispositions which lead to a "eat-soup-from-a-bowl instinct"? Of course not, it comes about because being burnt is aversive to all humans, and the fact that flat plates result in hot liquids like soup spilling over into our laps.

The fact that learning often produces universal behaviors is exactly that; a scientific fact. The existence of these behaviors is what prompts us to be able to distinguish an innate cause from a learnt one when looking at universal behaviors. Sure, in many cases we can argue that it's "reasonable" to assume innate over learning, or we can assume that it's probably an evolutionary adaptation, but science requires more than that to reach conclusions - we need evidence. I have absolutely no problem accepting that there are sex differences in the manifestation of mating behaviors, but if someone presents a specific example that they believe demonstrates this, then I'll be interested and ask them for a link to the study which attempted to distinguish innate explanations from learning explanations. If no studies can be found, I'll remain skeptical of concrete conclusions.
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Re: Hard-wired behaviours in human males and females?

#19  Postby Beatsong » Dec 23, 2012 1:28 am

Mr.Samsa wrote:
Beatsong wrote:The fact that there are similar, clear and consistent differences between the behaviours of the sexes in those other species most related to us - without any influence of culture - is the first clue.


But the point I was making was that there is no necessary reason for us to think that we should expect to find them. There are good reasons to suspect that there may be differences, like you mention, but I don't think this justifies a strong claim like "we should expect to find them".


We may be interpreting the phrase "expect to find them" differently. I didn't see that as suggesting that there is positive, undeniable proof of them; only that the likelihood that they are there is higher than the likelihood that they are not. I saw "expect to find" as referring to where we think we are most likely to find the evidence, in the absence of having sound the evidence YET.

Thus we are talking about what seems plausible, rather than what there is already evidence for. As I described, the idea that the human sexes evolved with similar behavioural differences to our closest relatives, seems more plausible than the idea that they created some extraordinary exception within the field of mammalian biology. The idea that the brains of the sexes developed differences in tandem with the organs and processes that it interacts with, is more plausible than the idea that it didn't.

Actually there is already empirical evidence emerging for differences between the female and male brain, although I would obviously admit that it's a very new area of enquiry with massive complexity of which we have only just scratched the surface. But the OP was not about that; it was about what seems more likely given the admittedly incmplete state of our knowledge.

Beatsong wrote:We then basically have two ways of accounting for the differences between human males and females:

1. Just like chimpanzees etc, we have evolved different behavioural patterns for males and females, connected with their different physiology, reproductive nature etc.

OR:

2. All of those other species evolved such different behaviours, but at the point that our evolution split off from theirs, we miraculously reversed all that and quickly re-evolved men and women to behave largely the same way instead. Even more miraculous, however, we then invented culturally imposed norms of behaviour and designed them especially to LOOK as if they were evolved ones like those other species had!

It's pretty obvious which side Occam is shaving on here.


Occam's razor doesn't work that way. You have to present the evidence first and find which explanation accounts for the most data with the least amount of assumptions - we don't simply look at the answer which is the simplest.


But what I've presented IS evidence. It may not be definitive proof, but it is evidence. All mammals suckle their young, have hair, are warm blooded etc. etc. If we discovered a species that conformed to the accepted description of "mammal" in every way we know of except for one, then we would expect, before finding the evidence to confirm it, that that remaining way would conform as well - at the very least, that it is more likely to conform than not.

Importantly, there are huge and significant differences in the physiological and psychological development of humans compared to chimps, so using the same pseudo-Occam's principle, we could equally say that it is unreasonable to assume that similarities in other species will translate to humans.


Nobody's assuming anything - we're simply talking about what is most likely. And 98% of the genetic makeup to chimpanzees and humans is the same. We have much the same organs situated in the same places doing the same things. Of course there are differences, but given the total variety of organisms in the world and the variety of ways it is possible for them to develop, the differences are massively dwarfed by the similarites.

The point is not that there are no differences, but all I'm saying is that we need evidence before even bringing up Occam.


But don't you also need evidence of the opposite?

In fact it seems to be you who is doing the assuming. You seem to think we should assume a default starting point that there are no differences between men and women, and that evidence gained from other species is irrelevant, until we have absolute compelling evidence to the contrary. But you have not provided any basis for that assumption. There is no actual reason why a difference of zero between human males and females is any more likely than a difference of some other magnitude.

So until you provide some evidence why we should think there will be no (or hardly any) hardwired difference between male and female behaviour, I am happy to go along with the OP in simply examining the evidence we have either way, and coming to a provisional estimation of which seems more likely. Given the massive complexity of the subject and the number of interacting variables, I suspect we're going to be in pretty much that place for a good while yet.

Sure, we can certainly argue that the brains of men and women could have evolved differently to deal with different issues. The problematic part is the assumption that differences in the physiology of the brain will result in differences in behavioral patterns.


But they invariably do, in every area that we know anything much about.

Beatsong wrote:The idea that behaviour can be completely separated from physiology is ridiculous, so if there are different physiologies, there will be differences of behaviour. We know for example that behaviour is influenced by hormones - witness PMT, puberty and menopause. We also know that human males and females have a very different hormonal makeup from each other. Do the math.


It's not ridiculous at all. Knowing that there are different physiological effects in different sexes gives us reason to suspect that there are differences in brain physiology, and differences in brain physiology gives us reason to suspect that there are differences in behavior, but this isn't a deductive argument and one does not necessarily lead to the other. It would be premature and unscientific to assume that we should expect to see behavioral differences due to differences in brain physiology.


Again, I haven't assumed anything. But given the importance of the brain in all aspects of behaviour where its role has been studied, it would be more likely that the two are linked than not - which is the way the OP was framed. If evidence emerges to the contrary, then I will be surprised but I won't ignore it. You presumeably agree with this anyway because if you didn't, why would one give you "reason to suspect" the other?

Beatsong wrote:Recent studies have found, for example, that girl babies born with congenital adrenal hyperplasia (who produce excessive androgen hormones) produce behaviour more like that traditionally considered "typically male", than like that of other girls. And this continues even after their hormone levels have been normalised - ie the effect of the particular hormonal balance on the developing brain is permanent.


And that's interesting but it would essentially work against the point you're making. If men and women have evolved different brains due to the differences in levels of hormones and other brain chemicals, then flooding a "female brain" with "male chemicals" would tell us nothing about how a "male brain" is affected by or processes "male chemicals".


No that doesn't make any sense. Postulating differences between male and female brains doesn't suggest that they are like aliens from different planets and nothing is similar about them! Any reference to such difference is a reference to statistical averages. For example the idea that men are better at maths and women are better at language. The jury is still out on the nature/nurture question in relation to that, but ignoring that for the moment, it doesn't mean that the way women process language tells us NOTHING about ho men process language! They are differences of degree, emphasis, etc. within the same basic organ. And indeed we know that certain sex hormones do have similar effects upon the behaviour of men and women, so it would make complete sense that they also have similar effects upon brain development.

And the fact that these kinds of behaviours are pretty much universally seen in the males of mammal species rather than the females, is just a co-incidence of learning? Like, one day a male happened to do it, and ever since then all the males in every subsequent generation have learnt to do it from their dads, while it's never occurred to any females to do it? And this just happened to be the case in every species where aggressive sexual rivalry is observed?


You are presenting a very narrow form of learning there. Learning is not limited to explicit learning (i.e. teaching) or observational learning (seeing another individual perform the behavior). It also comes about through the natural interaction with its environment. When you have organisms with the same basic traits and they're placed in the same basic environment, then it is inevitable that they will perform some behaviors which are exactly the same purely as a result of environmental factors. For example, a popular example when teaching this topic of species-specific constraints producing universal behaviors is the fact that all people, of all cultures, of all times, have always eaten hot liquids from a curved container (e.g. bowl or cup) rather than something flat like a plate. Is this because there are innate predispositions which lead to a "eat-soup-from-a-bowl instinct"? Of course not, it comes about because being burnt is aversive to all humans, and the fact that flat plates result in hot liquids like soup spilling over into our laps.


Interesting angle. But how are the environmental factors influencing the males of most mammal species so very different from thos influencing the females, that this learning would be so consistently stratified along sex lines?

The fact that learning often produces universal behaviors is exactly that; a scientific fact. The existence of these behaviors is what prompts us to be able to distinguish an innate cause from a learnt one when looking at universal behaviors. Sure, in many cases we can argue that it's "reasonable" to assume innate over learning, or we can assume that it's probably an evolutionary adaptation, but science requires more than that to reach conclusions - we need evidence. I have absolutely no problem accepting that there are sex differences in the manifestation of mating behaviors, but if someone presents a specific example that they believe demonstrates this, then I'll be interested and ask them for a link to the study which attempted to distinguish innate explanations from learning explanations. If no studies can be found, I'll remain skeptical of concrete conclusions.


But what you actually seem to be saying is that if no studies can be found, you'll ASSUME that the sex differences are due to learning rather than innate factors.

Why?
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Re: Hard-wired behaviours in human males and females?

#20  Postby Calilasseia » Dec 23, 2012 6:18 am

Tangential diversion for a moment ...

After clicking on one of MacDoc's links, I was intrigued by the idea that rhesus macaques exhibit statistically significant preferences, despite being completely out of the loop of human society, so to speak. So, I went looking to see if there was a paper coupled to that statement, and lo and behold, here it is:

Sex Differences In Rhesus Monkey Toy Preferences Parallel Those Of Children by Janice M. Hassett, Erin R. Siebert and Kim Wallen, Hormones and Behaviour, 54(3): 359-364 (August 2008) [Full paper downloadable from here]

Hassett et al, 2008 wrote:Abstract

Socialization processes, parents, or peers encouraging play with gender specific toys are thought to be the primary force shaping sex differences in toy preference. A contrast in view is that toy preferences reflect biologically determined preferences for specific activities facilitated by specific toys. Sex differences in juvenile activities, such as rough and tumble play, peer preferences, and infant interest, share similarities in humans and monkeys. Thus if activity preferences shape toy preferences, male and female monkeys may show toy preferences similar to those seen in boys and girls. We compared the interactions of 34 rhesus monkeys, living within a 135 monkey troop, with human wheeled toys and plush toys. Male monkeys, like boys, showed consistent and strong preferences for wheeled toys, while female monkeys, like girls, showed greater variability in preferences. Thus, the magnitude of preference for wheeled over plush toys differed significantly between males and females. The similarities to human findings demonstrate that such preferences can develop without explicit gendered socialization. We offer the hypothesis that toy preferences reflect hormonally influenced behavioral and cognitive biases which are sculpted by social processes into the sex differences seen in monkeys and humans.


Now last time I checked, rhesus macaques weren't subject to pressures of the sort routinely stated to be present in human societies, so this result is interesting to put it mildly. However, what would add weight to the hypothesis presented in the paper, is if this sort of statistically significant correlation was observed in a non-primate species. Anyone up for devising an experiment to test toy preferences in dolphins?

Apparently the above paper is not the only paper documenting relevant empirical research. There's also this one:

Sex Differences In Response To Children’s Toys In Nonhuman Primates (Cercopithecus aethiops sabaeus) by Gerianne M. Alexander & Melissa Hines, Evolution & Human Behaviour, 23(6): 467-479 (November 2002) [Full paper downloadable from here]

Alexander & Hines, 2002 wrote:Abstract

Sex differences in children’s toy preferences are thought by many to arise from gender socialization. However, evidence from patients with endocrine disorders suggests that biological factors during early development (e.g., levels of androgens) are influential. In this study, we found that vervet monkeys (Cercopithecus aethiops sabaeus) show sex differences in toy preferences similar to those documented previously in children. The percent of contact time with toys typically preferred by boys (a car and a ball) was greater in male vervets (n = 33) than in female vervets (n = 30) (P < .05), whereas the percent of contact time with toys typically preferred by girls (a doll and a pot) was greater in female vervets than in male vervets (P < .01). In contrast, contact time with toys preferred equally by boys and girls (a picture book and a stuffed dog) was comparable in male and female vervets. The results suggest that sexually differentiated object preferences arose early in human evolution, prior to the emergence of a distinct hominid lineage. This implies that sexually dimorphic preferences for features (e.g., color, shape, movement) may have evolved from differential selection pressures based on the different behavioral roles of males and females, and that evolved object feature preferences may contribute to present day sexually dimorphic toy preferences in children.


A commentary paper by Alexander & Hines on the Hassett et al paper can be found here, along with another commentary paper here by a third collection of authors. From the latter commentary paper, we have this interesting pair of paragraphs:

We know of at least two other examples of male–female cognitive differences that resemble the interesting pattern that appears in the toy choice data of Hassett et al. (2008): visual recognition memory (McGivern et al., 1997) and spatial navigation (e.g., Sandstrom et al., 1998; Williams et al., 1990;Williams and Meck, 1991). In both of these cognitive domains, females appear to process information comprehensively, while males appear to select and respond to only certain types of information. For example, when visual recognition memory for male-oriented objects (e.g., drawings of balls, bikes, sports equipment, and motor vehicles), female oriented objects (e.g., drawings of human and animal figures, cooking and sewing items, girls' clothing) or random objects (e.g., drawings of household items, office objects, furniture) was assessed in children and adults, females performed equally well when presented with all three types of stimuli, and males only performed as well as females when the objects were male-oriented (McGivern et al., 1997). These data are particularly striking because the authors ruled out a language-based explanation of their findings by including a more difficult task in which a single neutral object differed only in its internal pattern; thus, these objects would be difficult to name. While the performance of all subjects for this task was very poor compared to memory of nameable objects, females still outperformed males. These findings suggest that this sex difference in recognition memory may be the result of differences in visual attention. Male bias to attend to male-oriented objects may account for their increased performance only on this category of objects.

Males, but not females, also show strong selectivity in information processing of spatial information. When a navigation task may be solved by using either local or distal cues, male rats (e.g., Brown and Moore, 1997; Sava and Markus, 2005; Suzuki et al., 1980) and rhesus monkeys (Herman and Wallen, 2007) tend to use distal cues, while females are able to use either type of cue (Herman and Wallen, 2007; Tropp and Markus, 2001), suggesting that females may be more likely to attend to both types of information while males focus on one type of cue. This difference can also be seen if rats' use of spatial information is probed after male and female rats reach equal asymptotic performance on a radial-arm maze task (Williams et al., 1990). Female rats are not disrupted in performance if either landmark (e.g., the computer, experimenter, cart with cages) or geometry (e.g., the rectangular room shape) is removed or obscured. However, males are completely reliant on room geometry; their performance is severely disrupted if the room shape is obscured, even if large salient landmarks in the room remain to guide navigation. In this case, it appears that for males, the Euclidian properties (i.e., angles and distances) that define the environmental landscape (e.g., test room) overshadow the large salient landmarks, and are the default information for spatial navigation, while females appear to process both environmental geometry and landmark cues comprehensively, and can use either set of cues to navigate. Interestingly, these effects are organized by perinatal hormone exposure, as males castrated at birth rely on both landmarks and geometry similar to adult ovariectomized females; and neonatally estrogen treated females show reliance on geometry, just like adult castrated males (Williams et al., 1990). Thus while circulating hormones may further alter navigation strategies (e.g., Korol, 2004), they are not required for these sex differences in cue use.
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