Peter Dews attended medical school at the University of Leeds where he received his Bachelor of Medicine and Bachelor of Surgery degrees, and then joined the subdepartment of Pharmacology at Leeds, at the time headed by Professor W.A. Bain. His work at Leeds on the pharmacology of an extract of marijuana gave him an early appreciation of difficulties in objectively studying the behavioral effects of drugs.

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Dews also spent time with Burn in Oxford (1946) and with Gaddum in Edinburgh (1947), and came to the United States in 1948 when he was offered a two-year Research Fellowship at Burroughs Wellcome in Tuckahoe, New York. It was at Wellcome that he conducted his first published study on the behavioral effects of drugs (Dews, 1953). He accepted a Fellowship at the Mayo Foundation where he served from 1950 to 1952, and earned his Ph.D. in Physiology (1951) in the laboratory of Charles Code at the University of Minnesota. For the next year worked with Joseph Berkson in the Division of Biometry and Medical Statistics at the Mayo Clinic, during which his interest in statistical analysis and estimating error took form. This interest continued throughout his career, and particularly flourished when he later turned his attention to risk assessment in behavioral toxicology.

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Dews was hired to the post of Instructor in Pharmacology at Harvard Medical School in January 1953 by Professor Otto Krayer, and spent the remainder of his academic career at Harvard. Krayer told Dews to call on B. F. Skinner in the Department of Psychology at Harvard University, who had told Krayer that he (Skinner) had techniques that would be useful in pharmacology. The results of that meeting were colorfully recounted by Dews at a meeting of the European Behavioural Pharmacology Society (Dews, 1997). Dews met briefly with Skinner, and was then shown around the laboratory by Skinner’s younger associate, C. B. Ferster. As Dews tells the story, he immediately felt at home in the laboratory; he sensed that he had found what was needed to objectively study the behavioral effects of drugs. The functional character of the laboratory was more like a physiology or pharmacology laboratory than what he had expected from a psychology laboratory. The likely leading contribution to his comfort with the laboratory environment was the kymograph-like tracings of the cumulative recorders drawing records of behavior occurring in time, and in systematic relation to environmental events.

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Dews and Ferster immediately launched studies on the behavioral effects of drugs, some of which were published in Ferster and Skinner’s compendium, Schedules of Reinforcement (Ferster and Skinner, 1957). And with Ferster’s generous loan of apparatus, Dews launched a program of objective studies of the behavioral effects of drugs (e.g. Dews, 1955a, 1955b, 1957, 1958; Wurtman et al., 1959). His initial experiments established that the schedule of reinforcement that maintained a repeating behavior could play a critical role in determining the effects of pentobarbital. Not only were the dose-effects of the drug different for the performances maintained under two different schedules of reinforcement, but there was actually a dose range at which the rate of behavior was increased under one schedule and decreased under the other. That is, the effects of a drug on behavior could be diametrically opposite, depending on the schedule of reinforcement that controlled the behavior. In subsequent research, Dews investigated the effects of drugs on discriminatory performances and the behavioral effects of stimulants. In his work on stimulants Dews discovered that “stimulant” drugs would increase the probability of behavior, as was assumed by the name of the loosely defined drug class; but also, and just as importantly, the drugs could decrease the probability of behavior. Whether the likelihood of the behavior increased or decreased depended on the probability (or rate) of the behavior when the drug had not been administered. This “rate-dependency principle” had precedents in pharmacology (e.g., Langer and Trendelenberg, 1964), and formed an important launching point for many subsequent studies of the behavioral effects of drugs by Dews and scores of others.

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In the years that followed, Dews built a Laboratory of Psychobiology, first within Professor Krayer’s Department of Pharmacology, and later in the Department of Psychiatry at Harvard. With the addition of William H. Morse, and later Roger T. Kelleher, the laboratory flourished. There was a steady stream of medical students and post-doctoral fellows that spent a few years in the laboratory under the mentoring of one of the three principals before moving on to good positions elsewhere. The first and foremost subject of study was the behavioral effects of drugs. However, consistent with Professor Krayer’s receptive appreciation of subjects normally thought of as outside the realm of pharmacology, the Laboratory of Psychobiology took on a wide variety of subjects of study. From within the Laboratory itself or through collaborations within the Harvard community, Dews and members of the Laboratory examined schedules of reinforcement as determinants of behavior, environmental influences on visual behavior (in collaboration with Torsten Wiesel), behavioral and environmental influences on cardiovascular function (with J. Alan Herd), substance abuse, and behavioral toxicology.

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Perhaps one strength that Dews had in his approach to the subject matter of behavioral pharmacology, was that he was not formally trained in psychology. Being “a mere pharmacologist” he was not constrained by psychological theory, and he approached behavioral studies with methods and techniques that appealed to him as an experimental pharmacologist. Early in his career he had declined suggestions that he study the behavioral effects of cannabinoids by examining rodents in mazes. Most important to Dews was that his methods produce objective and quantifiable data, and that studies emphasized functional relations between independent and observable dependent variables. The insistence on objectivity and quantifiable functional relationships was not restricted to studies of behavior. Dews approached questions of fundamental pharmacological importance with the same objectivity that characterized the Laboratory’s pioneering behavioral studies (see for example, Woods and France, 2002). Characterizing all of his endeavors was a reliance on sound principles of behavioral and pharmacological science. This approach continues to invigorate the best work in behavioral pharmacology, and surely must be viewed as the legacy of Peter B. Dews.

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