Disruptive effects of contingent food on high-probability behavior.

The team asked a simple question. If you give a child food right after she plays with a toy, will she play more? They set up a single-case lab study. Ten seconds of toy play earned either a bite of food or a plastic token.

Sessions alternated so each child served as her own control. The toy stayed the same. Only the consequence changed.

Food backfired. Toy play dropped when food followed it. Kids also tried to open the food box or ask for more snacks. Tokens did not hurt play.

The food itself acted like a cue that screamed "eat now." The toy could not compete.

Older lab work saw the same drop, but with non-contingent food. Edwards et al. (1970) and Harper (1996) gave pigeons free snacks and watched key-pecking slow down. Their food was not earned; the new study shows even earned food can hurt.

Neef et al. (1978) also found response-independent food suppressed baseline responding. The 2012 paper extends this by proving the contingency alone does not protect the behavior. The edible stimulus itself drives the trouble.

Pritchard et al. (1987) showed contingent food keeps responding higher than free food, yet the new data reveal a limit. If the food cues competing responses, contingency cannot save you.

You may use edible reinforcers every day. This study warns that the bite you hand over can pull the client toward food-seeking instead of the target skill. Watch for dips in engagement right after food delivery. If you see them, swap to tokens, praise, or brief activities. The reinforcer should support the behavior, not advertise lunch.