Combined effects of ethanol and diazepam on performance and acquisition of serial position sequences by pigeons.

The effects of diazepam and ethanol, alone and in combination, were studied in pigeons responding under acquisition and performance chain schedules. Both diazepam and ethanol increased the number of pecks on the incorrect key (errors). Under the acquisition schedule both diazepam and ethanol increased errors at doses lower than those under the performance schedule. Under both schedules effects of combinations of ethanol and diazepam were usually greater than the sum of the effects of the individual drugs.