Effects of d-amphetamine and ethanol on responding of squirrel monkeys maintained under fixed-ratio schedules of food presentation and stimulus-shock termination.

Effects of d-amphetamine and ethanol were assessed on comparable behaviors maintained under fixed-ratio schedules of either food presentation or termination of electric shock and an accompanying visual stimulus. Ethanol affected the behaviors similarly in all important aspects; d-amphetamine increased rates of responding maintained by stimulus-shock termination at doses that did not affect rates of food-maintained responding. The increases in responding maintained by stimulus-shock termination were not solely due to decreases in the pause prior to the initiation of responding.