William H. Morse (1928–2026)
Written by Jonathan L. Katz, James W. McKearney, and James E. Barrett
William Herbert Morse died on February 28, 2026, while hospitalized near his home in Gig Harbor, Washington. Morse divided his retirement years between his home there and a second home at tranquil Quathiaski Cove, on Quadra Island in British Columbia. His retirement years were peacefully spent with his wife, Pat, and their dogs, with regular visits from his children and their families.
Morse attended college at the University of Virginia where he studied with the psychologist, Frank W. Finger, and earned a BA (1950) and an MA (1952) in psychology. From there he went on to earn his PhD in psychology at Harvard University in B. F. Skinner’s laboratory in the basement of Memorial Hall in Cambridge, MA. His time at Harvard working with Skinner was exceedingly influential, along with daily interactions with a cadre of other PhD candidates including, among others, Nathan Azrin, Richard Herrnstein, and Skinner’s associate Charles Ferster. Morse and Herrnstein collaborated on several studies on schedule-controlled behavior as each pursued their own doctoral theses. Morse’s doctoral dissertation examined the discriminative control of behavior, and elucidated factors that contributed to responding during the periods without reinforcement. Morse found behavior controlled by schedules of reinforcement to be fascinating and he authored a definitive analysis of the control of behavior by schedules of reinforcement (Morse, 1966), a continuing theme that would involve his research for the remainder of his career.
During the time Morse was a graduate student, Peter Dews from the Department of Pharmacology at Harvard Medical School started visiting Skinner’s laboratory to study the effects of drugs on the orderly behaviors generated by various schedules of reinforcement. Those visits proved to be another important influence as Morse and Herrnstein, under the tutelage of Dews, initiated behavioral pharmacology studies of their own. In one of these studies (Herrnstein and Morse, 1956), pentobarbital was administered to subjects responding under the control of a complex schedule of reinforcement that included a fixed-ratio element. The performances after drug administration showed instances of the hallmark high rates of responding generated by fixed-ratio schedules that were not apparent before the drug was administered. This result is likely the first instance of a drug treatment revealing an otherwise masked aspect of the control of behavior.
On the recommendation of Dews, Professor Otto Krayer, the Chair of Pharmacology at Harvard Medical School, supported Morse as a Milton Research Fellow in Pharmacology when he was still a graduate student in Psychology. Once Morse obtained his PhD, Dr. Krayer further supported him with an appointment in the Pharmacology Department where he would remain for the entirety of his career.
Morse learned pharmacology from Dews, Krayer, and the empirical surroundings of the department, and became fully immersed in teaching medical students with, among other procedures, the Heart-Lung preparation that Krayer perfected for research and teaching. Dr. Krayer became another compelling influence on Morse, as well as the nascent field of behavioral pharmacology. Krayer reviewed manuscripts submitted for publication from those in his department, which Morse later said could be “a humbling experience.” He strongly encouraged Morse and R. T. Kelleher to write a comprehensive paper on behavioral pharmacology (Kelleher and Morse, 1968a) that was published in Ergebnisse der Physiologie Biologischen Chemie und Experimentellen Pharmakologie, the premier international publication of pharmacological review papers, and he influenced The Journal of Pharmacology and Experimental Therapeutics to establish a Specific Field Editor in behavioral pharmacology.
By 1961, Dews, with encouragement from Morse, recruited Roger T. Kelleher, a psychologist from Smith Kline & French Laboratories to join the research group at the Psychobiology Laboratory. Morse and Kelleher established a magnificently productive collaboration on studies of behavior and behavioral pharmacology. Among their first substantial contributions was a paper published in Federation Proceedings that critically reassessed the commonly accepted view that many behaviorally active drugs, especially those used to treat psychiatric illnesses, have selective effects on behaviors “motivated” by escape from aversive stimuli (Kelleher and Morse, 1964). They noted a critical limitation in earlier comparisons was that the schedule maintaining positively and negatively reinforced behaviors were typically different, which inevitably produced differences in both the form and likelihood of the behaviors maintained. In view of an earlier finding by Dews that drugs could affect behaviors maintained by the same reinforcer differently depending on the schedule of reinforcement, Kelleher and Morse developed both positively and negatively reinforced behaviors under different schedules of reinforcement. The performances maintained and the effects of drugs depended more on the schedule of reinforcement than on the reinforcer that maintained the behavior. These results, together with those from several subsequent studies, cast strong doubt on the thinking at the time that a major factor determining the effects of drugs was whether the behavior was under control of positive or negative reinforcement.
Together, Morse and Kelleher also initiated a series of studies on the control of behavior by noxious stimuli, including studies on the maintenance of behavior solely by the presentation of electric shock (Kelleher and Morse, 1968b). At first blush, the finding that a noxious event can maintain the behavior that results only in its presentation may appear counterintuitive, as noxious stimuli are typically assumed to suppress behavior when presented following a response. As Morse and Kelleher (1977) noted, behavior maintained by noxious stimuli may be viewed as a contamination of well-established logical definitions, however “it brings the range of phenomena studied in laboratory settings closer to those of ordinary behavior” (p. 198).
Morse and Kelleher also explored the influence of environmental and behavioral variables on cardiovascular function. Collaborating with Drs. Dews and J. Alan Herd of the Physiology Department at Harvard Medical School, they showed that reinforcement contingencies can modulate cardiovascular responses and, in some cases, promote pathological hypertension (e.g., Herd et al., 1969).
Teaching was an important part of the operations of the Psychobiology Laboratory, a continuation of Dr. Krayer’s tradition. Morse invested substantial efforts into the annual lectures and extraordinary demonstrations for medical students, which emphasized the role of the environment in the behavioral effects of drugs (Marr, 2006). Additionally, the role of the environment was regularly a part of the formal research conducted in the Psychobiology Laboratory. Consistent with Dr. Krayer’s appreciation of topics traditionally thought of as outside the realm of pharmacology, subjects of formal study ranged widely, and included behavioral and environmental influences on cardiovascular function, substance abuse, behavioral toxicology, and environmental influences on vision. As the laboratory evolved and expanded over ensuing years, Morse (with Kelleher and Dews) mentored a succession of notable post-doctoral fellows, graduate students, medical students, and visiting scientists from around the world that went on to make their own substantial contributions to science.
Looking back on those times Dews later remarked that having Morse join him “was the best thing that could have happened to the laboratory. We complemented one another and he taught me a great deal of which psychology was a small part” (Dews, 1987). Morse reminisced years later (Morse, 2005) that his initial reluctance about studies with drugs was overcome by the genuine interest in behavior that Dews possessed, and that he enjoyed talking with Dews, and almost 50 years later still did.
Bill Morse is survived by his wife Pat, daughters Carla, Sarah, Melissa and son Will and their families. He and Pat have eight grandchildren and one recently born great grandchild. One of his children had this to say: “One of the things that I always loved about my father was that he seldom said anything negative about people. He had an appreciation for people being themselves and thinking for themselves. My father was so happy to be with the people he loved.”
References
- Dews, P.B. (1987). “An outsider on the inside.” Journal of the Experimental Analysis of Behavior, 48: 459–462.
- Herd J.A., Morse W.H., Kelleher R.T. and Jones L.G. (1969). “Arterial hypertension in the squirrel monkey during behavioral experiments.” American Journal of Physiology 217: 24–29.
- Herrnstein R.J. and Morse W.H. (1956). “Selective action of pentobarbital on component behaviors of a reinforcement schedule.” Science, 124: 367–368.
- Kelleher, R.T. and Morse, W.H. (1964). “Escape behavior and punished behavior.” Federation Proceedings 23: 808–817.
- Kelleher, R.T. and Morse, W.H. (1968). “Determinants of the specificity of behavioral effects of drugs.” Ergebnisse der Physiologie Biologischen Chemie und Experimentellen Pharmakologie 60: 1–56. (a)
- Kelleher, R.T. and Morse, W.H. (1968). “Schedules using noxious stimuli. III. Responding maintained with response-produced electric shocks.” Journal of the Experimental Analysis of Behavior 11: 819–838. (b)
- Marr, M.J. (2006). “A major trio.” Journal of the Experimental Analysis of Behavior 86: 355–357.
- Morse, W.H. (1966). “Intermittent reinforcement.” Operant Behavior: Areas of Research and Application, ed. W.K. Honig, pp. 52–108. New York: Appleton-Century-Crofts.
- Morse, W.H. (2005). “An appreciation of the genius of B.F. Skinner.” The Pharmacologist, 47(2), 53–59.
- Morse, W.H, and Kelleher, R.T. (1977). “Determinants of reinforcement and punishment.” Honig, W.K., Staddon, J.E.R., eds. pp. 174–200. Handbook of Operant Behavior. Englewood Cliffs, NJ: Prentice Hall, Inc.