Behavioral determinants of drug action. The contributions of Peter B. Dews

Abstract

Peter B. Dews played a significant role in shaping the distinctive characteristics and defining the underlying principles of the discipline of behavioral pharmacology. His early and sophisticated use of schedules of reinforcement in the 1950s, incorporated from research in the experimental analysis of behavior and integrated into the discipline of pharmacology, provided tremendous insight, inspiration, and impetus to the newly emerging field of behavioral pharmacology. The experimental findings generated by Dews' research, blending the sophisticated use of behavior and pharmacological principles together with the elegant manner of their presentation and far-reaching implications, provided the force and momentum to establish and direct behavioral pharmacology for several decades. This article attempts to capture some of Dews' research that integrated and inspired the blending of sophisticated behavioral work with that of pharmacology.

Fig 1. Effects of pentobarbital on key pecking of pigeons responding under either a FI 15-min (open circles) or a FR 50 (filled circles) schedule of food reinforcement.

Control (nondrug) response rates are shown on the left above SAL (Saline). The drug effect is expressed as the ratio of the mean response rate after the drug to the mean response rate before the drug on the same day. The ratios were averaged across the four pigeons. Each point represents the arithmetic mean of the ratios for the same 4 pigeons at each dosage level on each schedule. For the Control points, the mean of the ratios represents sessions in which saline was injected and compared to the noninjection response rates. Note that pentobarbital produced increases in responding under the FR schedule at doses (1.0 and 2.0 mg/kg) that reduced responding under the FI schedule. Modified from Dews, 1955a.

Fig 2. The relationship between mean rates of responding in individual 25-s periods under control conditions and following administration of amobarbital.

X-axis: log of the rate of responding as responses per session (the fixed interval was 500 s, divided into 25-s periods; the 20 periods within each FI were cumulated over the course of the session); Y-axis: change in log response rate following amobarbital. There are 20 points on each graph, 10 representing periods when the houselight was present (shown as circled triangles), and 10 representing periods when the houselight was not present (shown as triangles). The numbers in parentheses represent the pigeon number. Note the inverse relationship between control response rate and the effects of amobarbital with the lower response rates in the stimulus associated with nonreinforcement (i.e., houselight present, circled triangles) showing larger increases following amobarbital. After Dews, 1964a.