I am not sure it is true that mathematical intelligence peaks early, people like to say it though and I'd be interested if there is evidence on it. Here are a

I am not sure it is true that mathematical intelligence peaks early, people like to say it though and I'd be interested if there is evidence on it. Here are a lot of examples of good contributions by older mathematicians. https://math.stackexchange.com/questions/1059235/great-contributions-to-mathematics-by-older-mathematicians https://math.stackexchange.com/questions/1059235/great-contr... I think one factor is that young people tend to be hungry to achieve something and also aren't burdened with family or admin which means they can work harder.