> but how do I assign a number to "magnitude in the change of behavior"?
You don't. Read what I wrote.
> You've not defined a "hegemonic group" either.
If you're interested, look it up. I feel a strong sense of deja-vu.
> maybe you can clearly state a hypothetical observation which would prove your theory incorrect
I think I've done it twice in the past when talking to you, so I'll only provide a short abstract here (and again, it's not my theory but the consensus theory): If groups with power were not to resist social mobility (i.e. for less powerful groups to obtain more power) we'd see a constant shift in power distribution, which would be very fluid, while what we observe is the complete opposite: a very stable power structure that then breaks and gets restructured relatively very rapidly during revolutions that are rare. So the pattern is long periods of stability and then quick changes brought about by some explosive event or a demonstrable pattern of slow power acquisition through many struggles. When it comes to women, the pattern is often the latter (there's a simple explanation for that), but you can see how women gain access to politics, law, medicine etc. only after very long fights against very strong opposition (that invariably cite innate ability as the barrier).
> For example, to disprove my "more math less women" theory, you should find a broad category of similar careers, run linear regression on math content vs % female, and find a flat or upward sloping line. I.e., the same analysis as was done on Scott Alexander's post (see my link), but with the opposite result.
Two problems with that. First, yours is not a theory but a description. Second, it is not a very relevant one because it doesn't explain the constant change in participation, nor the gender-gap in the software industry. Finally, while "more math less women" may have always held on average, the slope has changed. I don't think anybody minds if the gender distribution in physics is 60-40%, even if that difference is entirely due to innate ability. So your description does not even compete with mine because it doesn't even try to explain the same phenomenon, which is the one we care the most to explain.
That has little to do with the 4:1 or even 10:1 difference we see in the software industry.