You have to love it when someone burbles, “I’ve finally realized after all these years that I was doing X all wrong” immediately before making the very same bad life choice he or she just claimed to have put in the past. No, really, I do. The ability to simultaneously learn from a mistake and make that mistake repeatedly anyway is an exquisitely human thing. (I don’t like it when someone who happens to consider me a mortal adversary plays this game, but this is rare, even if it’s what inspired this post.)
In practical terms, wild animals with small brains alter their behavior in accordance with reward-punishment schemes much more readily than people do. If a lizard eats a plant that makes it sick, thanks to its limbic system and the intimate relationship between olfaction and memory, that lizard will never eat that type of plant again. A human, on the other hand, is inclined to engage its cerebrum, and concludes things like, “Well, maybe if I switch from vodka to beer, alcohol won’t be a problem” or “I’ll at least mix in some filtered cigarettes” or “As long as I limit myself to 10 tanning sessions a month, the gratuitous UVB rays really aren’t going to serve as a cancer risk.”
Ironically, we’re the only animals smart enough to be capable of completely pulling the wool over out own eyes. We readily conflate being aware of a problem to having solved it with no further effort.
Is this trait adaptive? It certainly helps reduce cognitive dissonance, which always provides psychological relief, but in general — no. It allows people to repeatedly engage in behaviors that cause them pain, and the fact that it exists to a more obvious degree in mentally unstable but otherwise fairly intelligent or even very intelligent people seems to suggest that it’s not a good approach to the world.