TECHNIQUE FOR SUSTAINING BEHAVIOR WITH CONDITIONED REINFORCEMENT.

Pigeons were intermittently reinforced with food for pecking at one key. Concurrent pecking at a second key intermittently produced conditioned reinforcers (the set of stimuli that accompanied food reinforcement, but not the food). Under these conditions, responding on the second key was maintained indefinitely. Rates and patterns of responding on the second key were a function of the schedule of conditioned reinforcement.