Stephen E. Glickman

Steve Glickman, a leading scholar in behavioral endocrinology, animal behavior, and evolutionary biology, died on May 22, 2020. He was born in the Bronx, New York, on January 17, 1933. His mother was an accomplished piano teacher affiliated with the Julliard School and his father was a junior high school math teacher. In his childhood, he made frequent visits to the Bronx Zoo, where his lifelong connection to animals was nurtured.

After graduating from Brooklyn College in 1954 with a degree in psychology, Steve attended graduate school at Northwestern University. A visit from Donald Hebb, the Canadian psychologist and pioneer in the neural basis of learning, convinced Steve to transfer to McGill University in 1956, where he obtained a Ph.D. in physiological psychology, supervised by Hebb and Peter Milner. In his dissertation, Steve investigated the effects of electrical stimulation of the brain on rats’ learning and the reinforcing properties of arousal, with emphasis on the reticular activating system. Three years later, this work led to his foundational article, titled “Perseverative Neural Processes and Consolidation of the Memory Trace” (Psychological Bulletin, 1961), a work years ahead of its time and one that foreshadowed the explosive growth of research on the brain’s mediation of learning and memory.

Steve returned to Northwestern in 1958 as a junior faculty member. Before leaving in 1965, he spent two years as a Miller Fellow at Berkeley, sponsored by Frank Beach. During this time, studying both skunks and rats, Steve completed the manuscript describing his landmark study of curiosity in diverse species at Chicago’s Lincoln Park Zoo (“Curiosity in Zoo Animals”, Behavior, 1966). In this study, he characterized and quantified the reactions of more than 200 captive vertebrate species to a standardized set of novel objects, revealing significant differences among various taxonomic groups, both in the quantity and form of object manipulation. This work again foreshadowed important current research on species’ differences in exploration and neophilia. In 1965, Steve accepted an associate professorship at the University of Michigan, where he stayed for two years before moving to Berkeley where he would spend the remainder of his career. While at Berkeley, Steve published over 100 peer-reviewed journal articles, including prestigious publications in Proceedings of the National Academy of Sciences, Science, and Nature. His contributions to ecology, evolution, animal behavior and intelligence and, of course, behavioral endocrinology, will be long lasting.

Throughout his career, Steve employed a powerful comparative approach to questions about behavior, comparing terrestrial and aquatic turtles, as well as diverse mammalian species, such as Mongolian gerbils, domestic cats and rats, dusky woodrats, striped skunks, the common moles, the spotted hyena, and many others. In 1967, he co-authored the landmark “A Biological Theory of Reinforcement” (Psychological Review, 1967), a classic paper that is still cited. In this paper, Glickman and Bernard Schiff proposed a simple theory of reinforcement that could explain the range of apparent disparate behaviors observed across species in reaction to specific stimuli. They argued that reinforcement evolved as a mechanism to ensure species-typical responses of approach and avoidance. In their theory, preserved neural circuits found in the brain stem could elicit complex and species-dependent behaviors of approach or avoidance, and expected stimuli would act as positive reinforcements, promoting further approach or further avoidance. This positive feedback loop shaped by evolution would serve as a foundational circuit to enable other types of learning, such as those found in classical conditioning, where an unexpected stimulus could reinforce an approach behavior or alternatively an avoidance behavior. This theory exemplifies many aspects of Steve’s approach to biological research: the inspiration obtained from observing behavior in multiple animal species, the appreciation of evolutionary mechanisms, and the formulation of simple yet elegant and powerful theories.

In the 1980s, Steve began his famous work focusing on the spotted hyena, and was awarded NIH funding to establish a breeding colony at the field station in the Berkeley hills above campus, adjacent to Tilden Park. This unique colony began with a group of ten infant hyenas that Steve and his collaborators collected in Kenya in 1984 and 1985. Because of the Berkeley climate, hyenas could be kept year-round in very large outdoor enclosures, allowing many natural behaviors to be expressed, including social behaviors such as scent marking, greeting ceremonies, social play, and mating. The Berkeley colony became the largest colony of captive spotted hyenas in the world and served as a pole of attraction for researchers.

Steve’s own work there focused on the neuroendocrine mechanisms underlying sex differences in this atypical species, known for its female-dominated society, where females have masculinized genitalia. His collaborator and pioneer in field studies, Laurence Frank, had initiated this research in Africa but convinced Steve that further progress could only be achieved in a more controlled environment. Steve, Laurence, and collaborator Paul Licht focused on the hormones responsible for this unusual anatomy during sexual differentiation. They hypothesized that the evolutionary costs of this masculinization was offset by the benefits of female dominance in spotted hyena society. Throughout many investigations involving many collaborators, it was discovered that the male hormone testosterone was not directly or solely responsible for this female masculinization but that, in addition, high levels of the pro-hormone androstenedione secreted by the hyenas’ ovaries, as well as differences in the timing of sexual hormones binding globulins, played important roles in this unusual sexual development. These novel routes and dynamics of masculinization helped explain the development of masculinized genitalia in females and the larger size and dominance in females relative to male hyenas while preserving some of the female-specific behaviors (“Spotted hyaenas and the sexual spectrum: reproductive endocrinology and development”, Journal of Endocrinology, 2020). This comprehensive research project revealed the limitations of a male-centric and single species approach for studying sexual biology; in attempting to understand the biology of an exceptional and exotic species, Steve and his colleagues revealed our lack of knowledge and understanding of the multiple pathways involved in sexual differentiation. This research on an extraordinary species provided multiple insights on particular clinical cases of abnormal sexual development in humans. Finally, in addition to observing sex differences in a number of behaviors in the spotted hyena such as juvenile play, scent marking, and meeting ceremonies, Steve also studied “animal intelligence” in the spotted hyena including coalition formation and vocal communication.

The Berkeley Hyena Project became a great attraction for U.S. and international researchers, with faculty from UC Berkeley, UC Davis, UCLA, UCSF, UC Santa Barbara, Duke University, Cornell University, Kansas State University, Michigan State University, Stanford University, the University of British Columbia, the University of Massachusetts, the University of Texas, and the University of Lyon/St Etienne (France) visiting the facility to interact with Steve, Mary Weldele, the long-time coordinator of the Hyena Project, and the hyenas themselves. In 2020, the Berkeley Field Station was renamed the “Stephen Glickman Field Station for the Study of Behavior, Ecology and Reproduction” in honor of Steve’s scientific contributions to the interplay of evolution and animal behavior and the creation of this unique research environment.

In addition to his theoretical and empirical research on behavior, Steve imparted his passion for evolution and animal behavior in his lectures and teaching. He always grounded his lecture materials in the greater historical context of the discoveries, as he was also a scholar of the history of psychology. His lectures on the relationship between Charles Darwin and Alfred Russell Wallace captivated generations of students as well as faculty. Wallace, in particular, was a favorite because of his underdog status, which appealed to Steve, who also had replicated one of Wallace’s most important journeys in Malaysia with his wife Krista. Whether teaching the history of science, animal behavior or physiology, Steve was able to captivate his audience; the lecture material was rigorous but it was delivered by an extraordinary storyteller. In 1975, Steve was a recipient of Berkeley’s Distinguished Teaching Award.

As chair of the Department of Psychology for five years (1977-82) and through service on many committees, Steve championed the fair treatment of women and people of color and forged new links among different disciplines within his department. He also served on various Academic Senate committees, including the Berkeley Division Committee on Budget and Interdepartmental Relations (BIR), Committee on Teaching (COT), and the Animal Care and Use Committee.

Steve’s friendships were legion. And to anyone who knew him, heard him lecture, or had seen him extolling the personalities of his hyenas at the Field Station, the deep affection and even reverence felt by so many of us was not surprising. Among us all – colleagues, students, and friends – Steve was known for his humility, intelligence, generosity, kindness, and empathy. This humility mixed with curiosity – the qualities that made him such a powerful intellectual and researcher – also made him a great listener and a dear friend. The outpouring of sincere expressions of love and respect at his passing was indeed overwhelming. Steve is deeply missed both as an inspiring scientist and a cherished friend.

Lucia Jacobs
Frederic Theunissen
Irving Zucker
2020