All of MadHatter's Comments + Replies

This was an amazing article, thank you for posting it!

  • Side tangent: There’s an annoying paradox that: (1) In RL, there’s no “zero of reward”, you can uniformly add 99999999 to every reward signal and it makes no difference whatsoever; (2) In life, we have a strong intuition that experiences can be good, bad, or neutral; (3) ...Yet presumably what our brain is doing has something to do with RL! That “evolutionary prior” I just mentioned is maybe relevant to that? Not sure … food for thought ...

The above isn't quite true in all senses in all RL algorithms. F... (read more)

1Steve Byrnes2y
That's interesting, thanks! I agree that this is a very important dynamic. But I also feel like, if someone says to me, "I keep a kitten in my basement and torture him every second of every day, but it's no big deal, he must have gotten used to it by now", I mean, I don't think that reasoning is correct, even if I can't quite prove it or put my finger on what's wrong. I guess that's what I was trying to get at with that "evolutionary prior" comment: maybe there's a hardcoded absolute threshold such that you just can't "get used to" being tortured, and set that as your new baseline, and stop actively disliking it? But I don't know, I need to think about it more, there's also a book I want to read on the neuroscience of pleasure and pain, and I've also been meaning to look up what endorphins do to the brain. (And I'm happy to keep chatting here!) I don't have a full explanation of comparing-to-baseline. At first I was gonna say "it's just the reward-prediction-error thing I described: if you expect candy based on your beliefs at 5:05:38, and then you no longer expect candy based on your beliefs at 5:05:39, then that's a big negative reward prediction error. (Because the reward-predictor makes its prediction based on slightly-stale brain status information.) But that doesn't explain why maybe we still feel raw about it 3 minutes later. Maybe it's like, you had this active piece-of-a-thought "I'm gonna get candy", but it's contradicted by the other piece-of-a-thought "no I'm not", but that appealing piece-of-a-thought "I'm gonna get candy" keeps popping back up for a while, and then keeps getting crushed by reality, and the net result is a bad feeling. Or something? I dunno. Oh, I think there's also a thing where the brainstem can force the high-level planner to think about a certain thing; like if you get poked on the shoulder it's kinda impossible to ignore. I think I have an idea of what mechanism is involved here … involving acetylcholine and how specific and con