As an amateur chess player (2000/rapid/lichess) I wouldn't say the speed or amount of thinking I do has changed as I've gotten better in terms of the number of moves I evaluate. In fact it feels like I frequently think less now than when I was worse.

My brain has compressed/chunked patterns so that I can immediately see what the optimal move or set of candidate moves are instead of having to determine them more computationally.

I'm not sure how that fits into the framework of this article. Something like the number of calculations remains static but total work done per calculation increases.

Much of the debate in this comment thread is a result of these concepts being fuzzily defined in the article itself.

You memoized some of the computation.

"Think rate is fixed" glosses over activities with compounding returns. Learning!

Better abstractions and heuristics can have an enormous impact on problem solving efficiency.

First-principles thinking is a powerful hammer, but it's expensive. Over-use it and you'll get nothing done. Under-use it, and you'll do nothing original. Knowing where to use it is the trick, and that's _also_ a skill that can be improved over time.

Chess GMs certainly prune better, but can also evaluate moves faster because they can easily hold multiple boards in their head. It's common for strong GMs to play 10+ blindfold simul games. Nakamura solving chess puzzles is a sight to see.

How is knowing what to prune not thought?

Sometimes it is, then it would be thinking in this context. Other times it's pattern matching which isn't analytical thinking.

I’m still having a hard time understanding the distinction. How is pattern matching not thinking?

This distinction is captured in "Thinking Fast and Slow"

https://en.wikipedia.org/wiki/Thinking,_Fast_and_Slow