Children's or young adult novel based on ideas of classical conditioning

I'm trying to remember a book that is probably middle-school grade and is about a group of children kept in a room (or perhaps series of rooms, like a maze) who I believe are test subjects of some sort. They are given food only sporadically and they try to figure out what action they need to perform in order to get food--like rats pressing a lever in psychological experiments. I think they try a number of different actions and movements but are never truly able to figure out what leads to the release of food. I believe it ends with one of the subjects being set free, and his/her conditioning is activated when he or she sees a traffic light. The light turns and he or she does the elaborate set of movements "learned" while in captivity.

House of Stairs, maybe?

Definitely, though it's the whole group set "free" at the end and dancing at the traffic light.

Definitely House of Stairs by William Sleator. It's on the frequently sought stories list, linked both on the book page and Name That Book home page...