Thanks for your thoughtful reply.
Gotraskhalana wrote:Why do I think so? I think so because I encountered the same attitude when I learned languages (and other things related to youth stereotypes) and because I teach a lot and encounter people of different ages and their various attitudes and success.
Count me as one of your encounters

Interestingly enough, I also came to my opinion through my experiences learning and teaching languages. My impression is that it gets harder to remember vocabulary as one grows older, and that younger people can better internalize the sounds and flow of a foreign language.
I also have long experience with learning in the face of stereotypes against women in my domain and this discussion feels familiar.
I also see some similarities in these discussions. Some argue that inherent abilities are more important than external factors or the other way around. It seems obvious to me that both are important.
Do I think that age doesn't play much of a role? It certainly plays a big role whether you have young children and a career while learning go or not, but I don't think that this is what you are talking about. You seem to be genuinely convinced that you would have had much better results if you had started go at age 20 and did exactly the same things. I think that this difference would have been very small.
Yes, we disagree. All things being equal, I do think that if I was 20 and put as much time and energy into go as I have since I started in my mid 40's that I would be significantly stronger. I am 100% sure that if I had put in this time and energy as a 6 year old, that I would be significantly stronger. Of course you are right that all things are not equal, so it is indeed hard to make a comparison.
The relevant questions are: If you were 20 and not progressing at go as fast as you want, what would you do? And why don't you do the same thing now?
Who says I'm not doing what I would have been doing then?
Stereotype threat means that you do worse when "people" expect you to do worse. It is well-documented and studied and the people who are most affected by it are (potential) high-achievers during test situations with hard problems who don't need to believe the stereotype themselves. Studies indicate that it is simply very distracting if at every little failure you have to reflect whether this corroborates the stereotype threat or how you are confirming the stereotype for those who believe it.
Some classical study set-ups:
1. You let some American male college students play a tricky mini-golf course. You tell half of them that this problem is a good indicator of athleticism, result: the Black students excel. You tell half of them that this problem tests strategic planning and intellect, result: the White students excel. And the difference is not subtle.
2. You give a maths test to Asian-American female college students. You ask half of them whether they are housed in single sex dorms or not. You ask half of them whether they speak languages other than English. Those that are reminded that they are Chinese do a lot better on the maths test than those that have been reminded that they are women.
Interesting studies! I don't doubt that psychological factors play a role in one's ability to perform a task and that positive thinking is beneficial to performance, but it's only a relative factor. In other words, psychological conditions will help or hinder one compared to how they would perform without being subject to such influences. They don't cancel out other possible influences such as age.
It also seems that these studies are dealing with the short-term effect of an external suggestion and not with the long-term effect of an internalized opinion. For me, whether it's true or not, I view the idea that age affects one's abilities as an obvious fact, like today being Sunday. It's not something that distracts me much.
There are ways to mitigate the effect and I have found that I have used some of these ways in my own life instinctively. However, I still feel that people who emphasize a lot that "X cannot do Y well" are engaging in an aggressive action against me if I am part of X, want to do Y and the sentence is not part of an actual discussion whether it is true, but simply repeated over and over and over again as an unsupported statement of fact. And I find it hard enough that there are practically no women in this endeavour. I certainly don't need a second stereotype threat on top of that.
I do think that it is true that age affects one's ability to perform and learn, and I base this on my own experience and observations. For example: there are a lot more people who started playing go when they were young and are now strong than there are people who started playing when they were older and are strong. A recent thread mentioned that the age of the strongest chess players averages to about 31 years old, and I assume that it is slightly younger for go players. Either their abilities start to decline after that, or they are not learning the newest moves as well as younger players.
I guess similar to what you describe, I take offense to the claim that age is not relevant. People who say that X has no influence on my ability to do Y while I feel that X is a limiting factor are to me discounting my accomplishment when I perform Y at a certain level.
Interestingly enough, it is also possible to view a stereotype threat as a challenge. This has been my approach to learning Chinese, and I think it is working well. The notion that Chinese is a hard language for a native English speaker to learn, and that it is even harder to learn as an older adult is a big source of motivation for me. My Chinese is better than that of anyone I know who has started learning at my age and has not lived in China. If I didn't see it as a challenge, I probably wouldn't know any Chinese at all.
Patience, grasshopper.