The Emergence of Behavioral Pharmacology

Effects of pentobarbital on key-pecking behavior of pigeons under fixed-ratio and fixed-interval schedules. In a fixed-ratio (FR; solid circles) schedule, food is delivered following 50 pecks; in the fixed-interval schedule, food is given in response to the first peck that occurs after 15 minutes. Each schedule was correlated with a distinctively colored response key, and the schedules alternated throughout the experimental session. Note that response (i.e., pecking) rates decrease under the FI schedule at doses of pentobarbital (i.e. 0.5 – 2 mg, noninclusive) that correspond to increases in response rates under the FR schedule. (SAL, saline). Modified from (5) .