Inhibitory stimulus control and the magnitude of delayed reinforcement.

Pigeons pecked a key for food. Sometimes the food came after a short delay. Sometimes it came after a longer delay. The delay itself was always the same length, but the amount of food waiting at the end was bigger or smaller.

The researchers watched how the birds responded during the delay signal and later tested if the signal still slowed responding when it appeared in new places.

Bigger food piles made the birds stop pecking more. The delay signal became a stronger “don’t peck” cue.

Later, when the same signal showed up on other keys, the birds still pecked less. Larger delayed reinforcers built stronger inhibitory control.

Selekman (1973) showed that any signaled delay can act like a red light. The new twist here is that making the reinforcer bigger makes the red light brighter.

Catania et al. (2015) zoomed in on time. They found that delayed reinforcers also strengthen responses that happened seconds earlier. Together the papers say: delay hurts, and bigger delayed pay hurts more.

Reed (1991) looks like a clash. With immediate food, bigger piles sometimes sped rats up. The difference is timing. Immediate big food can juice responding, but big food that is still seconds away slams on the brakes.

If you use token boards, sticker charts, or points that trade in later, keep the backup reinforcer small but valued. A huge promised reward teaches the learner to wait, not to work. Shrink the magnitude, shrink the wait, and you keep momentum in the session.