system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does our brain decide that we like/dislike something?
gpt
A study conducted in Israel in 2014 suggests that people's preferences essentially boil down to conditioning, in a process very similar to that used by Ivan Pavlov to train his dog. In his now-classic experiment, Pavlov rang a bell every time he fed the dog. After a while, the dog began to salivate any time it heard the sound of the bell, anticipating being fed.

Prof. Yadin Dudai and Dr. Avi Mendelsohn conducted a study on 40 Israeli people. The subjects were shown a Japanese character for a very brief period of time, and they could choose whether to press the space bar or not. Half of these characters earned the participant a shekel (roughly equivalent to a quarter in US dollars) if they pressed the space bar, and the other half deducted one shekel from their winnings. If they did not press the space bar, nothing happened. On each subsequent play of the game, participants earned more money, despite intermediate tests showing they were not consciously aware of which characters were the "money makers."

Three days later, the participants were invited back to the lab and shown the "money making" characters, the "money losing" characters, as well as some new "neutral" characters, and asked which ones they preferred. The participants showed a strong bias towards preferring the characters which had earned them shekels during the game.