Hypnotism and Suggestion: A Historical Perspective
Authors: Lamont Peter 
Published: March 2020

Franz Anton Mesmer’s theory of “animal magnetism” proposed that living organisms possess an invisible magnetic fluid, which can be influenced by a “magnetizer” and, by doing so, a variety of illnesses can be cured. Contemporaries, such as the Marquis de Puysegur, took a more psychological view, claiming that a state of “artificial somnambulism” could be induced, through which alternate states of consciousness, and clairvoyant powers, could be exhibited. Public demonstrations of mesmeric phenomena, from insensibility to pain to clairvoyance, convinced many that there was something to it, whether as a medical tool or, perhaps, as evidence of supernatural powers. The distinction between mesmerism and hypnotism, made explicit in the writings of James Braid, distinguished between such phenomena, attributing the latter to fraud, and the former to suggestion. With the decline of mesmerism, facilitated in part by Braid’s theory and the introduction of chemical anesthesia, the more extraordinary phenomena of mesmerism, and the concept of a mysterious force, became part of the spiritualist and mind-cure movements, and the basis of psychical research.

In the last quarter of the 19th century, a revival of scientific interest in hypnotism in France led to a dispute between two schools of thought: in Paris, hypnosis was explained in terms of an inherited pathological disposition; in Nancy, it was regarded as a normal process, and the product of suggestion. Hypnosis was used to explore the “dissociation” of personality and “sub-conscious” processes, provoking various theories about alternate selves in the normal and abnormal mind. At the turn of the 20th century, while clinical interest continued, experimental interest turned to the concepts of suggestion and suggestibility, which had practical educational, political, legal, and commercial relevance. A new line of hypnosis research, based on experimental, quantitative methods with normal subjects, began in the United States in the 1920s, and concluded that hypnosis was nothing more than suggestion. In the second half of the century, renewed scientific interest led to competing theories that explained hypnosis either in terms of a hypnotic state or else in terms of social roles. The dispute between “state” and “no state” theories was accompanied by a debate over the existence of a stable individual trait that might explain individual differences in hypnotizability. Meanwhile, as the effects of social influence became a significant topic of study, the implications for psychology experiments were considered in terms of “demand characteristics” and “experimenter effects.” In the last quarter of the 20th century, there was significant interest in legal issues relating to hypnosis, particularly concerning “recovered memory,” and the accusation that false memories and multiple personalities were the product of suggestion. As debates about the nature of hypnosis continue, the descendants of mesmerism, from “anomalous cognition” to “social priming,” which provoked recent debates about the limits of psychological methods, demonstrate the ongoing relevance of studying the boundaries of the mind.