Response-produced timeouts under a progressive-ratio schedule with a punished reset option.

Three behavioral options were available to food-deprived pigeons: (1) pecking one key resulted in food reinforcement according to a 50-response progressive-ratio schedule, (2) pecking a second key reset the progressive-ratio schedule to the initial progressive-ratio step, and (3) pecking a third key produced a 3-min timeout period. Pecks on the reset key were shocked. Under low and intermediate shock intensities, timeouts were not produced; under high shock levels, timeouts were produced regularly. Timeouts occurred during the initial period of a progressive-ratio step and were more frequent during the longer steps of the progressive-ratio schedule. Response-produced timeouts under these experimental conditions could be interpreted either as an escape from aversive behavioral options or as a low-probability behavior emerging when the food reinforcement schedule exerted weaker control.