First, I'm not sure how much learning precisely you were expecting from the troll in this limited period of time, most of which was taken up by it feeling fly-bites and smacking around the flies, nor even how you would expect for such to be seen.
Secondly, it did seem to learn. George hit it with three Ventus spells, each one moving it further towards the edge of the terrace. Between the second and the third, the troll dug its hand into the stone, anchoring it in place so that it would not be blown over the edge. If that's not adapting to match a new threat, I'm not sure what would be--certainly not in the brief time of the fight where most of the attacks were on the level of fly-bites.
If that is not displaying a learning ability, I would like to hear an example of a learning ability that it could have displayed.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 90. The previous thread has passed 750 comments.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,18,19.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: