The interresponse interval as a measure of bar pressing behavior in normal and drugged rats.

Abstract
Rats were tested in a Skinner box with 100% reinforcement. The frequency distributions of intervals between bar-pressing responses were studied under control conditions and following injection of dexedrine, chlorproma-zine, Frenquel, and pentothal. Intervals from 1/2 to 3 sec. were called "multiple responses"; those from 3 1/2 to 11 sec., "normal"; and those greater than 11 sec., "interruptions." Dexedrine greatly increased the frequency of multiple responses. The 3 depressant drugs showed an increased number of errors in responding and an increased number of interruptions. The overall pattern of depression could not be attributed to any single pharmacological action of the drugs.