In the case of the sitcom Seinfeld, the characters seemed obnoxiously stoic, but that doesn't mean they didn't learn anything. In fact, we don't know, but that's part of the comedy. Actually, it's for the viewers to learn something, not the actors.
Anyway, I can't be quick to judge people who aren't so preachy and forward about stuff. I don't know what's in their heart.
By people's actions, we would get to know if they're actually learning anything from experiences. There are actually people that don't learn anything from experiences. They would do the same thing, the same way, over and over again.