It's not unproven, there's ample literature and research on the fact.

Besides, the age pool of chess itself confirms it.

There's a single player in his 50s in the top 50 of chess and not a single 60+ in the top 100.

Also, even carlsen himself says he's no longer as good as he was years before and his mind isn't as strong.

Regarding sexism; most tournaments in Chess (including the world championship) are fully open and are thus gender netral: anyone can participate regardless of sex/gender and will compete on equal footing.

Women only categories have been created to give women visibility because they mostly were not able to reach advanced levels in the open format.

Some women choose to compete with men (Judit Polgár being a somewhat recent example) but most go straight to the women only tournaments to have a shot.

The men vs women « bias » is not unproven, they litterally had to create entire categories of competiton to account for it.

Cognition certainly declines with age at the population level. See e.g. https://pmc.ncbi.nlm.nih.gov/articles/PMC4906299/.

If the skill you need to select for is tactical combinatorics, then Chess dominance as a function of age would seem to support the premise of ageism.

What ageism ignores is that outside of chess, prescience outperforms other measures of productivity.

Can you provide at least three (3) peer-reviewed studies to support this?

> Ageism also just one of these shitty unproven biases

You might be right, if we were talking about anything except chess.

Chess, unlike everything else, has a clear ranking system and lots of records for people to analyze. And unfortunately, the record is very clear: chess ability decreases after a certain age.

However, the decrease is more likely due to stamina than mental decline. Chess tournaments take a long time, and stamina definitely decreases with age. However, pro athletes demonstrate that you can probably go until around your early 40s before it becomes a real issue.

Having said that, it will be interesting to see how this generation does in the blitz formats as they age. Those will be less dependent upon stamina and a better measure of mental acuity for chess.