Water-deprivation-produced sign reversal of a conditioned reinforcer based upon dry food.

The team worked with rats in a small lab. First they taught a clicking sound to work like food. The rats pressed a bar to hear the click, even when no food followed.

Next they stopped giving the rats water for a while. Then they tested the click again. The rats now acted as if the click was bad. They stopped pressing for it.

Water need flipped the click from good to bad. The same sound the rats once worked for became something they avoided.

This shows that a learned reinforcer can turn into a punisher just by changing the animal’s thirst level.

Embregts (2000) updates this idea. The paper calls thirst an “establishing operation.” It tells us to watch for any state that makes reinforcers gain or lose power.

NEVIN et al. (1963) looks like the opposite result. Noise kept rats pressing when it signaled escape from shock. The key difference is the type of need: escape from pain versus thirst. One need keeps the reinforcer strong; the other flips it.

KELLEHEBERRYMAELLIOTT et al. (1962) shows the same flip in people. When staff stopped giving attention for food refusal, meals became reinforcers again. Both studies say: check what the client is deprived of before you pick a reward.

Before you run a program, ask: is my client hungry, thirsty, tired, or needing a break? A star or token that worked yesterday can crash today if the child really wants water or a nap. Test reinforcers after a drink and again after a long recess. You may need two different reward menus for morning and afternoon.