“Inlying”, as opposed to “outlying”?
The fact that hate speech exists does not, by itself, equate to “All references are hate speech”.
Obviously not, which is why I never said that. But I was responding to Hector_St_Clare’s comment, and that was indeed broad and overstated.
The differences described by the bell curves plays into natural selection. Males on the higher end would be selected more frequently and they can impregnate multiple females.
Yes, except she carried the day. He didn’t even try to make a case, only said it ought to be studied. I don’t know why there are so few women in math, but she felt it was not something to study, but had to be the result of discrimination.
I don’t think you understand what you are responding to.
Over evolutionary history a mother’s death while her child is young would have great impact on the odds of the child surviving to reproductive age and success itself. The fitness cost of early adult death to a woman was thus high.
The adult male’s death OTOH would have had less impact on the survival of the child they have had to reproductive age: the fitness cost of moderately early father death was less.
Alternatively one can speculate that a positive outlier trait would have limited impact on a mother’s fitness success, possibly allowing her to attract a “better” mate or marginally to get one more child to reproductive age. Whereas a positive outlier trait in a male could theoretically result in many additional progeny: a big potential payoff. In some early systems the positive outlier’s success was huge and being other than the outlier was associate with little reproductive success at all. Average or horribly below average both had very little reproductive success; only top dog mated and they mated often with many.
I’d call it steeper vs. broader bell curves.
Did I miss something? Everyone’s saying “yes, it’s true” without offering proof. And even if it may be true in some cases, surely it can’t be true for every single human trait.
The Variability Hypothesis for mental traits originated in the early 20th century but was challenged by later work.
I’d like to ask Shagnasty for some cites for his assertions on the question.
What are you asking for specifically? You are a scientist. My academic training is in the sexual differentiation and behavioral neuroscience of psychology. It is difficult to break decades worth of scientific results into a few short paragraphs so I decided to keep it short and simple because it is true. Nearly all sex-independent measurable traits on the statistical bell curve show a few males at the top. That should be blatantly obvious even to casual observers.
We can look at individual traits selectively and prove that it is true one by one or we can explore the theories about why that is. Which question are you most interested in? Be specific because, while I am happy to help educate, I am not interested in teaching both a statistics and behavioral neuroscience 101 class in this thread. This is one of those topics that is so well documented that it is actually difficult to cite unless the question is more refined. It is kind of like asking a chemist why they believe there are such things as atoms.
Generally, chemists will then be able to point to the work of J. J. Thomson and Rutherford, Rydberg and Bohr. Who would you point to as the equivalent of Rutherford for this topic in behavioral neuroscience, leaving aside the notion that you might need to teach Colibri, who IIRC holds a PhD in zoology or biology and has been a practicing scientist for years, statistics :dubious:.
While I’m generally happy with answers it’s true that this thread lacks confirming cites…
I know Colibri knows both science and statistics. I already said that. I suspect he is asking a leading question for the benefit of other readers. What I was getting at was what level of proof and/or cause does everyone want to know? It is one thing to ask about underlying causative processes and quite another to question that such differences exist in the first place at the very extremes. It is fairly easy to show that a few males score the highest on almost any specific mental or physical measure. It is much more work to go through the possible reasons why that is and unnecessarily technical if that wasn’t the question in the first place.
As I stated I can believe it is true, but the simple fact is that things that seem obvious, or that are “we all know that” often turn out to be false when critically examined.
“Highest” on any particular trait, for example, does not support the claim regarding variation about the mean. Use height … the mean for males is 5 inches higher than the mean for females. Same variation about the mean leads to the tallest males being taller than the tallest females. To the best of my knowledge however the variation about the mean for each is the same.
BMI? Several studies I can find demonstrate that females have greater variation about the mean than males, see specifically this CDC bar graph.
For blood pressure? Males were more normal.
Intellectual capacity? A bit more controversial. I could find this.
Those are just the first traits that come to mind and that I could find any data on.
What seems to be true, seems obvious without critical analysis, might not be. Or might be only for traits that are subject to sexual selection.
That said it is reasonable to speculate for reasons that it could be true, and it makes sense that it would be. Accepting the statement at as true however is a stretch.
I checked the growth charts by percentiles and was wrong on height - the 5 to 95% range in males at 20 years old is a 13 cm spread and in females the same age is 17 cm. In height male humans are more normative/less deviant/however you want to phrase it. You can also open up the BMI growth percentile curves there and see another example of greater variation about the mean in females graphically with girl percentiles being wider at almost every age. Boys slightly wider variation on head circumference. That’s the first of the things I’ve checked randomly that males did have convincingly greater variation about the mean.
Honestly I can’t find much support for the claim.
Perhaps limiting the discussion to a hypothetical assumption that it is true then what could be the reasons and/or mechanisms would be indicated?
Perhaps you could cite some review articles or even textbooks that summarize what is known on the subject. Failing that, perhaps some seminal articles on the subject. I at least have access to the technical literature.
Here are a couple of overview articles.
I don’t see much in those links that support your wide ranging claims. One cite in a wiki artilce that looked at male female sibships as the sole support for the claim of greater IQ variability, and math stating that it *varies according to culture *which gender has greater variability albeit males do in more of them.
Really neither is a review of the subject of broad male female phenotypic variability. The claim that a wider SD for males “occurs for almost every physical and mental trait that can be measured” is unsupported and the fact that the few I could find good objective large population measurements on find if anything the opposite to be true more commonly falsifies such a sweeping statement.
So here is a question -
Given that the examples I could find of traits that could be measured showed a slight tendency to more of them having greater variation about a mean in females than in males (height, BMI, blood pressure, and there are more, for example autoimmune disorders, another measurable trait, are much more common in females), why would that be?
The version “heard” by the op and claimed as true “for almost every physical and mental trait that can be measured” by Shagnasty is easy to make up just-so stories for. But why does it seem that the opposite is true? And why is the former version put out there so often without any real substantial basis?
Sorry to be both answering my own question and multiposting but googling about I really only see one context in which the claim of lower female SD is made: IQ discussion of the Bell Curve type with wider SD about the IQ mean (implicitly assuming that such reflects true genetic intellectual potential) as the explanation for why there appear to be more males of great intellectual accomplishment, and sometimes in a sense restricted to claims about math ability.
Note the first states as fact the claim without any basis provided and then discusses IQ and even more entertainingly in the other example the other than IQ example is a picture of one group of males and females claiming greater height variability in males … when large scale data shows conclusively that females have greater height variability!
Maybe there are a few more male lefties (it is debated) or males who are gay … not sure
Not so slam dunk to me.
Autism does seem to have a male predominance while, again, autoimmune diseases a female one.
The statement of greater SD in females seems to be a false one slipped because and believed because it has a good just-so story to go with it to justify Bell Curve IQ arguments for the lack of females at highest levels. (It’s not discrimination, it’s not sociology, it’s not that on average they aint as smart … just variation about the mean) Is that a Big Lie fallacy or does it go by a different name?
Shagnasty I’d be even interested in a list of several human traits that can be reliably consistently measured that have solid evidence of significantly greater male SD. Seriously most I can find goes the other way if at all.
Whenever this topic comes up I remember this presentation by Baumeister: Is There Anything Good About Men?
I recommend it, it’s an entertaining read.