Effects of alcohol on punished and unpunished responding of squirrel monkeys.

Lever pressing of two squirrel monkeys was maintained initially under a multiple 5 min fixed-interval 5 min fixed-interval schedule of food presentation where, in each of 2 separate stimulus conditions, the first response after 5 min elapsed produced food. Subsequently, during one of the fixed-interval components responding was punished by the presentat of a 5 mA electric shock following each 30th response; rates of responding were markedly suppressed during this component. Unpunshed response rates occurring during the alternate fixed-interval component remained unchanged for one monkey and decreased for the other. Alcohol (1.0-3.0g/kg) increased overall punished rates of responding and decreased unpunished response rates; at higher doses (3.5-4.0 g/kg) all responding was decreased. Where lower local rates of both punished and unpunished responding were comparable, as measured in successive quarters of the fixed-interval, these rates were increased equivalently with alcohol. Comparable higher local rates of punished and unpunished responding were both decreased to about the same extent. The effects of alcohol were determined by the control rate at which behavior occurred, irrespective of whether responding was punished or unpunished.