ESP and Parapsychology: A Critical Re-Evaluation, by C.E.M. Hansel, Buffalo, NY.: Prometheus Books, 1980, 325 pp., $15.95.
In 1966, Professor Hansel, who holds the chair of psychology at the University College of Swansea, University of Wales, published ESP: A Scientific Evaluation (Scribner's). It was soon recognized as the major scientific criticism of parapsychology. ESP proponents have singled out Hansel for the most vitriolic (and unspecific) attacks.
The World Almanac Book of the Strange claims: "most of C.E.M. Hansel's points against parapsychology have either been refuted or explained." But it never shows how Hansel has supposedly been refuted, or by whom. Curtis Fuller, editor of Fate magazine (which derives substantial revenue from the ads placed by supposed psychics and seers) writes that "many of [Hansel's] main tenets were discredited at the time of its original publication." Here again, the author never bothers to name who has refuted Hansel, or how. The reason for such attacks is that the criticism of parapsychology in Hansel's 1966 book was concise, compelling, and, if correct, utterly devastating to the claim that parapsychology as we know it represents a legitimate scientific endeavor.
Hansel has now revised and expanded his 1966 book, and the result has been printed by Prometheus, bringing the case of the skeptic up to date. Hansel's objection to parapsychology is twofold: first, he criticizes the procedures used in "classic" ESP experiments; and second, he criticizes the scientific philosophy underlying parapsychology.
One parapsychology "classic" is the Pearce-Pratt experiment, carried out in 1933-34 at Dr. J.B. Rhine's famous parapsychology laboratory at Duke University. Hansel visited Duke and secured the cooperation of the research staff to replicate the experiment, with himself as the subject. Hansel cheated, thereby obtaining extremely high scores and baffling the researcher about how it was done.
Another Duke "classic," the Pratt-Woodruff experiment, was criticized as having strong nonrandom features in its data selection as well as sensory clues, which could result in above-chance scores. In the British "classic" Soal-Goldney experiments of the 1940s, recent findings are cited which almost conclusively prove that some experimenter resorted to fraud. Hansel also shows how loose controls and careless experimental design invalidate the famous 1972-74 tests of Uri Geller at the Stanford Research Institute.
Hansel's criticisms of the parapsychologists' assumptions and methodologies are even more devastating than his criticisms of the experiments. He begins by noting that "telepathy is a new name for mind reading; clairvoyance for second sight; precognition for divination.…the experiments, if they can be relied upon, would imply that much of what has in the past been regarded as superstition must now be included in the domain of natural science."
Any experiment purporting to show the existence of ESP at, for example, the level of ten-billion-to-one-against a chance result proves nothing, he argues, unless it can be shown that the odds against fraud or experimental error are more than ten-billion-to-one. If the mind possesses "psychokinetic" powers, Hansel points out, capable of causing dice to come up with the desired value, how is it that gambling establishments worldwide continue to operate this and many other games of chance, and do so at a profit?
But the most serious criticism of all is the lack of repeatability in the experiments. "After 100 years of research, not a single individual has been found who can demonstrate ESP to the satisfaction of independent investigators. For this reason alone, it is unlikely that ESP exists." If any genuine, repeatable ESP phenomenon existed, Hansel argues, the skeptics would have been silenced long ago, no matter how sporadic the phenomenon. (High-scoring subjects invariably lose their powers whenever skeptics are present, or when experimental controls are tightened.)
"Science advances through a process of natural selection," Hansel observes. "The good (experiments) survive because they are confirmed in further research. The bad ones are forgotten because they cannot be confirmed.…if anyone invents a pseudoscience in which this principle ceases to operate, the result soon becomes apparent, for the new "science" fails to have predictive value and leads to more and more findings and theories that are incompatible with orthodox science. This is what has happened in parapsychology."
While Professor Hansel's ideas are carefully formed and directly stated, his writing style is often formal and academic. But no one who has completed college-level courses in the social sciences will find the book too difficult to follow. Some material from the first edition should obviously have been cut from the second: for example, in a case where experimenter fraud has recently been convincingly established, the reader should have been spared the lengthy discussions of possible sensory clues and nonrandom data.
Hansel's book will not reach as many readers as do the books of the ESP proponents, both because of his unwelcome message and his scholarly-sounding prose. Nonetheless, a serious challenge has been laid before "scientific parapsychology" (if such a thing exists). If parapsychologists continue to ignore Hansel, or to dismiss him with unspecific claims that his ideas have all been "refuted," it tends to suggest that Hansel has been right all along.
Robert Sheaffer writes frequently on popular scientific subjects. His book The UFO Verdict will be published in 1981.
This article originally appeared in print under the headline "Demythologizing ESP".