[sawwit]

It's because they have a much larger stack size than a human brain (which does not have a stack at all, but just various kinds of short term memories). An expert Go player can realistically maybe consider 2-3 moves into the future and can have a rough idea about what will happen in the coming 10 moves, while this method does tree search all the way to the end of the game on multiple alternative paths for each move.

[donmaq]

Not true. Profession go players read out 20+ moves consistently. Go Seigan's nemesis Kitani Minoru regularly read-out 30-40 moves.

As an AGAAmateur 4 dan I read 10 moves pretty regularly, that's including variations. And if the sequence includes joseki (known optimal sequences of 15-20+ moves), then pros will read even deeper...

[sawwit]

Yes, the latter number was perhaps too conservative; no doubt about deeper predictions being easily possible, but I doubt even expert players consider many alternative paths in the search tree. They might recognize overall strategies which reach many moves into the future, but extensive consideration of what will happen in the upcoming moves is probably constrained to a only few steps; at least relative to the number and depths of paths that AlphaGo considers.

[jibalt]

"while this method does tree search all the way to the end of the game"

No it doesn't. You seem quite happy to just make stuff up that you know nothing about, like "2-3 moves into the future".