Philip Zimbardo’s Contributions to the Field of Hypnosis (2026)
Donald Moss
College of Integrative Medicine and Health Sciences, Saybrook University, Pasadena, CA USA
Correspondence: dmoss@saybrook.edu
Key words: Philip Zimbardo, hypnosis, hypnotizability, cognitive, psychophysiology, time perception
Philip Zimbardo’s contributions to hypnosis can be best understood within the broader arc of his distinguished career in cognitive and social psychology. Although widely known for the Stanford Prison Experiment, Zimbardo consistently returned to hypnosis as a powerful experimental method for investigating cognition, emotion, motivation, and physiology. Trained in hypnosis at the Morton Prince Clinic and later serving as co-director of the Stanford Hypnosis Research Laboratory with Ernest Hilgard, Zimbardo approached hypnosis not as a curiosity but as a methodological instrument capable of testing core theoretical questions (Moss, in press).
His early enthusiasm for hypnosis reflected both scientific rigor and a dramatic flair. Personally skilled in self-hypnosis, Zimbardo publicly demonstrated hypnotic analgesia, illustrating the capacity of focused cognitive states to modulate pain perception. At a meeting of the International Congress of Psychology in London, he pierced his hand with a pin and dangled a heavy silver broach from the skin of his hand, as the audience looked on (Suzanne Sarnoff, Personal Communication). This experiential commitment paralleled his empirical investigations.
In his edited volume The Cognitive Control of Motivation (Zimbardo, 1969), he advanced a social-cognitive approach. Influenced by Leon Festinger’s cognitive dissonance theory and Neal Miller’s work on conditioned physiological responses, he explored how cognition interacts with biological drives. In a study with Rapaport and Baron (Zimbardo et al., 1969), participants underwent 12 hours of hypnosis training before being tested with electric shock and digit-span tasks. Subjects receiving hypnotic anesthesia instructions reported significantly reduced pain and showed decreased Galvanic Skin Response reactivity, demonstrating both subjective and objective modulation of the physiological response. Role-playing controls did not produce comparable effects, strengthening the case for hypnosis as more than simulation.
Zimbardo extended this mind-body inquiry in collaboration with Christina Maslach and Gary Marshall (Maslach et al., 1972). In experiments on voluntary temperature regulation, hypnotized participants successfully warmed one hand while cooling the other, achieving substantial thermal shifts. Non-hypnotized controls were unable to replicate these bilateral changes. The authors concluded that hypnosis amplifies cognitive influence over bodily functioning and suggested that reinforcement processes underlying psychosomatic symptoms may be cognitive in origin.
Further research examined posthypnotic suggestion, amnesia, and emotional arousal. In a study comparing highly hypnotizable and low-hypnotizable individuals, Zimbardo et al. (1993) found that unexplained physiological arousal—induced through hypnotic suggestion followed by amnesia—generated significantly greater distress and cardiovascular activation. When participants understood the source of arousal, emotional impact was reduced. This work supported a discontinuity hypothesis: arousal without cognitive explanation becomes hedonically negative.
In another study, Zimbardo et al. (1981) experimentally induced partial deafness to explore the social-cognitive roots of paranoia. Participants unaware of the hypnotic source of their hearing deficit displayed increased suspiciousness, hostility, and social withdrawal. The findings suggested that unexplained sensory changes may contribute to paranoid ideation, offering a cognitive-social mechanism relevant to hearing impairment.
During the 1970s, Zimbardo turned to time perspective, using hypnosis to manipulate subjective temporal orientation (Zimbardo et al, 1971). Participants instructed to expand the present while minimizing past and future showed shifts in affect, language, and sensory awareness. The hypnotized subjects showed a more dramatic change in their perception of time. This work laid the foundation for his later development, with John Boyd, of the Zimbardo Time Perspective Inventory, extending the construct into personality assessment and clinical intervention (Zimbardo & Boyd, 1999). Zimbardo also published a book with Richard and Rosemary Sword on a clinical therapy focused on time perspective (Zimbardo et al., 2012).
Zimbardo contributed to the Stanford longitudinal hypnotizability studies (Hilgard et al., 1961; Morgan et al., 1974; Piccione et al., 1989). Retesting participants over 10-, 15-, and 25-year intervals revealed striking stability in hypnotic susceptibility, with correlations comparable to those found in intelligence research. These findings, alongside heritability data from twin studies, positioned hypnotizability as a stable dispositional trait rather than a transient state.
His final hypnosis publication in 2022, co-authored with Etzel Cardeña and colleagues, examined relationships between hypnotizability and dispositional self-consciousness. Results underscored the multidimensional and complex nature of both constructs, resisting simplistic explanations (Cardeña et al., 2022).
Over the decades, Zimbardo used hypnosis to illuminate the power of cognition over physiology, emotion, and perception. His work combined theatrical demonstration with methodological rigor, contributing substantially to the recognition of hypnosis as a robust and scientifically legitimate phenomenon within psychology.
References
Cardeña, E., Lindström, L., Åström, A., & Zimbardo, P. G. (2022). Dispositional self-consciousness and hypnotizability. The International Journal of Clinical and Experimental Hypnosis, 70(1), 16–27. https://doi.org/10.1080/00207144.2022.2003695
Hilgard, E. R., Weitzenhoffer, A. M., Landes, J., & Moore, R. K. (1961). The distribution of susceptibility to hypnosis in a student population: A study using the Stanford Hypnotic Susceptibility Scale. Psychological Monographs: General and Applied, 75(8), 1–22. https://doi.org/10.1037/h0093802
Maslach, C., Marshall, G., & Zimbardo, P. G. (1972). Hypnotic control of peripheral skin temperature: A case report. Psychophysiology, 9(6), 600–605. https://doi.org/10.1111/j.1469-8986.1972.tb00769.x
Morgan, A. H., Johnson, D. L., & Hilgard, E. R. (1974). The stability of hypnotic susceptibility: A longitudinal study. International Journal of Clinical and Experimental Hypnosis, 22, 249-257. https://doi.org/10.1080/00207147408413004
Moss, D. (in press). Philip Zimbardo in the world of hypnosis. In C. Maslach, M. McDermott, & R. McDermott (Eds.), The Elgar companion to Philip Zimbardo. Elgar Press.
Piccione, C., Hilgard, E. R., & Zimbardo, P. G. (1989). On the degree of stability of measured hypnotizability over a 25-year period. Journal of Personality and Social Psychology, 56(2), 289–295. https://doi.org/10.1037//0022-3514.56.2.289
Zimbardo, P. G. (1969). The cognitive control of motivation: The consequences of choice. Scott Foresman and Company.
Zimbardo, P. G., Andersen, S. M., & Kabat, L. G. (1981). Induced hearing deficit generates experimental paranoia. Science, 212(4502), 1529–1531. https://doi.org/10.1126/science.7233242
Zimbardo, P.G., & Boyd, J. N. (1999). Putting time in perspective: A valid reliable individual-differences metric. Journal of Personality and Social Psychology, 77, 1271–1288. https://doi.org/10.1037/0022-3514.77.6.1271
Zimbardo, P. G., LaBerge, S., & Butler, L. D. (1993). Psychophysiological consequences of unexplained arousal: A posthypnotic suggestion paradigm. Journal of Abnormal Psychology, 102(3), 466–473. https://doi.org/10.1037//0021-843x.102.3.466
Zimbardo, P. G., Marshall, G., & Maslach, C. (1971). Liberating behavior from time-bound control: Expanding the present through hypnosis. Journal of Applied Social Psychology, 1(4), 305-323. https://doi.org/10.1111/j.1559-1816.1971.tb00369.x
Zimbardo, P. G., Rapaport, C., & Baron, J. (1969). Pain control by hypnotic induction of motivational states. In P. G. Zimbardo (Ed.), The cognitive control of motivation: The consequences of choice (pp. 136-152). Scott Foresman and Company.
Zimbardo, P. G., Sword, Richard, & Sword, Rosemary (2012). The time cure: Overcoming PTSD with the new psychology of time perspective therapy. Jossey-Bass.