The effects of brief stimuli presented under a multiple schedule of second-order schedules.

Pigeons pecked a key under a second-order schedule. Food came only after many fixed-ratio segments.

Each segment ended with a brief red light. For one condition the light always paired with grain. Later the same light never paired with grain. The researchers reversed the pairing to see if the light itself could keep the birds working.

When the brief light paired with food, pigeons pecked faster and paused less between ratios. When the pairing flipped, the effect flipped. The light acted like a tiny reinforcer even though no food came with it.

Kohlenberg (1970) used the same schedule one year earlier but added the drug chlorpromazine. That drug study showed the brief light controlled behavior more than the food itself, foreshadowing the 1971 finding.

Craig et al. (2017) moved the idea into an extinction context. They gave food-paired lights after lever pressing stopped. The lights slightly reduced resurgence, showing the same conditioned reinforcers can cushion relapse.

Belisle et al. (2017) ran a conceptual replication with humans playing slot machines. Bonus lights shifted choice even when the overall money stayed flat, mirroring how the pigeons responded to the red light independent of grain rate.

You can turn neutral stimuli into reinforcers by pairing them with what the client already wants. A click, a flash, or a short song can keep responding alive during long work stretches. Next time you stretch reinforcement schedules, add a brief paired stimulus between deliveries and watch if momentum holds.