Conditioned reinforcement in second-order schedules.

Pigeons pecked a key on a second-order schedule. A 0.7-second light flashed each time a fixed-interval part ended. Food arrived only after many parts.

The brief flash was paired with food every time. Researchers asked: can this tiny signal keep the birds working when food is rare?

The short flash worked like a mini-reward. Birds kept pecking and their rate climbed steeply inside each part.

Response stayed strong even though food came only after many flashes. The flash had become a conditioned reinforcer.

Kodera et al. (1976) later showed the flash only works if you first pair it with food and keep food coming sometimes. Kelleher (1966) proved the idea; L et al. filled in the rules.

Buskist et al. (1988) pushed the idea further. They found a half-second signal keeps pigeons pecking through delays up to 9 seconds. Longer delays need the signal to stay on, not just blink.

Fields et al. (1991) added a twist: d-amphetamine makes the flash even more powerful during extinction. The same brief stimulus grows stronger under drugs.

Your praise, a thumbs-up, or a beep on a tablet can act like that flash. Pair it with food, free time, or a toy a few times. Then use it to keep clients working while you stretch the big reward later. Check that the signal stays brief and you still give the real payoff now and then. This keeps conditioned reinforcers alive and strong.