2006 Donald O. Hebb Distinguished Contribution Award Winner
Dr. Shepard Siegel

Dr. Shepard SiegelDr. Shepard Siegel received his Ph.D. from Yale University in 1966, and has been at McMaster University since 1968. Hel has received international recognition for his research. He is a Fellow of the Royal Society of Canada, and has been awarded the title “Distinguished University Professor” by McMaster (there can be a maximum of only eight distinguished University Professors among the active faculty). He has received awards from a variety of Canadian (e.g., Canadian Psychological Association), American (e.g., Division of Behavioral Neuroscience and Comparative Psychology of the American Psychological Association), and international (e.g., Pavlovian Society) organizations. His research has been supported by federal funding agencies in Canada and the United States, as well as by industry. He is on the Board of Directors of several scientific societies, and is Editor-in-Chief of Learning and Behavior. Dr. Siegel has also contributed to the training of many scientists who have gone on to distinguished research careers, both in Universities and in the private sector. Dr. Siegel not only has been an excellent supervisor, but he also has been a very energetic one. He has produced more Ph.D.s than any other faculty member in the history of the Psychology Department at McMaster University. All are engaged in academic, industrial, or government positions in which they use the skills that they acquired in his laboratory. Dr. Siegel has received the highest recognition for graduate supervision awarded by McMaster University – “The University President’s Award of Excellence in Graduate Supervision.” Only one such award is made each year (selected from all faculty members in the Faculties of Science, Health Sciences, or Engineering).

Dr. Siegel started his research career with studies of fundamental mechanisms of the learning process. In 1975, he published a classic paper, widely reprinted in books of influential contributions to experimental psychology, indicating that learning principles are important for understanding how we associate environmental stimuli with the effects of drugs. That is, to understand drug effects (e.g., drug tolerance, and drug withdrawal symptoms), we must not only appreciate pharmacological principles, but also learning principles. Many otherwise inexplicable pharmacological phenomena are readily understandable by this approach that synthesizes findings from both the learning and the pharmacology research traditions.

Although an extensive description of Dr. Siegel’s contributions towards understanding drug effects is beyond the scope of this citation, it is possible to gain an appreciation of the work by considering the basic phenomena that inspired his research. People (and non-human animals) dependent upon drugs display heightened drug withdrawal symptoms and evidence of craving when confronted with cues that, in the past, have been paired with the drug. Thus, the heroin-addicted individual experiences withdrawal distress at the time of day that the drug usually is administered, or in locations or circumstances that have been paired in the past with the drug. Similarly, the cigarette smoker experiences withdrawal distress and craving especially in particular circumstances where he or she has smoked on many occasions in the past. Dr. Siegel has taken such casual observations, examined them with rigorous methodology in the laboratory, and has demonstrated how such drug-anticipatory responses importantly contribute to drug tolerance and dependence.

He (and many others, inspired by his research) has written about the implications of the research for understanding drug addiction, and the complications of addiction (i.e., enigmatic cases of drug overdose). His research on drug tolerance and withdrawal is notable for several reasons. Dr. Siegel essentially developed a new area of research involving a compelling integration of concepts from previously unrelated disciplines, and he has pursued the research at a variety of levels of analysis: behavioural, neurochemical, and molecular biological. His work is discussed in virtually every introductory psychology text, as well as text or reference books concerned with learning, psychopharmacology, drug abuse, alcohol, or opiates.

Although Dr. Siegel’s extensive contributions to psychopharmacology would make him a worthy candidate for the Donald O. Hebb Distinguished Contribution Award, it should be noted that, in recent years, he has extended his research to new areas. For example, he has pioneered the idea that tolerance to a drug is but one manifestation of the organism’s ability to attenuate the effect of repeatedly presented, potentially threatening stimuli. Thus, learning not only contributes to our ability deal with repeated pharmacological perturbations (i.e., drug tolerance), but also more generally to any repeatedly presented physiological insult. At a very fundamental level, the mechanisms of drug tolerance are similar to the mechanisms by which we maintain homeostasis in a variety of systems. Furthermore, he has applied his insights to integrate such seemingly disparate phenomena as the placebo effect and multiple chemical sensitivity disorder. Recently, he (together with Lorraine Allan) has discussed an exciting integration of concepts from learning theory and signal detection theory. Signal detection theory provides a mechanism for understanding how people judge whether a signal is present or absent when the task is difficult because the signal is presented in a “noisy” environment. The theory is relevant to the placebo effect because the patient must make a difficult judgment (Is the subjective symptom, such as pain or depression, ameliorated?) in an internal environment of symptoms of fluctuating intensities. Dr. Siegel’s has been invited to discuss these latest insights at the premier institutions in the world concerned with these topics (e.g., United States Environmental Protection Agency, National Institutes of Health, American Chemical Society). He has provided new paradigms for researchers in a variety of areas.

It is not hyperbolic to state that there are few psychologists comparable to Dr. Siegel. Like Dr. Siegel, there are many that study animal learning, or drug effects, or perceptual phenomena. We can think of few that study all these areas. This is not a manifestation of dilettantism. Rather, Dr. Siegel has taken all these disparate topics and combined them into a unified analysis of how Pavlovian conditioning affects the way we respond to a variety of chemical and non-chemical stimuli. It is unlikely that any other investigator has been invited to participate in symposia in such seemingly disparate areas as the Rescorla-Wagner model of learning, the pharmacology of drug addiction, the contribution of learning to homeostasis, perceptual aftereffects, multiple chemical sensitivity, and drug abuse policy. In all cases, Dr. Siegel has demonstrated the interrelationships among these seemingly disparate topics, the role of the psychologist in explicating phenomena in a variety of areas, and the importance of understanding the contribution of Pavlovian conditioning to the everyday life of humans and non-human animals.