The Psychokinesis article on Wikipedia is awful, just awful. Here, for the record, is some material I’ve recently added to try to bring scientific literature to bear on the topic:
A meta-analysis of 380 studies in 2006 found only a “very small” effect which could be explained by publication bias.(Bösch et al.) PK experiments have historically been criticised by scientists and skeptics for lack of proper controls and repeatability.(Girden, Humphrey) However, some experiments have created an illusion of PK where none exists, and this illusion depends to an extent on the subject’s prior belief in PK.(Benassi 1979)
It has been argued that cognitive bias could explain why people believe in PK even if it does not exist.(Blackmore) For example, Illusion of control is an illusory correlation between intention and external events, and believers in the paranormal have been shown to be more susceptible to this illusion than skeptics(Blackmore & Trościanko, Benassi) Bias towards belief in PK may be an example of the human tendency to see patterns where none exist, which believers are also more susceptible to.(Blackmore)
Physicist Robert L. Park cites Jahn’s PK experiments as examples of pathological science, sharing the feature of only producing positive results with statistical techniques where bias can be easily introduced. He argues that if PK really existed it would be easily and unambiguously detectable:
[I]f the mind can influence inanimate objects, why not simply measure the static force the mind can exert? Modern ultramicrobalances can routinely measure a force much less than a billionth of an ounce. Why not just use your psychokinetic powers to deflect a microbalance? […] The reason, of course, is that the microbalance stubbornly refuses to budge.—Robert L. Park, Voodoo Science, 2000, page 199
Park also complains of a lack of empirical progress; that despite many years of work by Radin, Jahn and other parapsychologists, “the results are no more convincing today than when they began their experiments. No mechanism is ever uncovered. No testable theory ever emerges”.
Psychologist Nicholas Humphrey considers a number of empirical and philosophical arguments against PK in his 1995 book Soul Searching. These include:
- Argument from Unawarranted Design: The circumstances under which macro-PK is supposedly demonstrated, such as manipulations of spoons or watches, are suspiciously similar to magic tricks, and obey constraints that a genuine psychic power would not obey.
- Ubiquity of experimental tests: Many experiments in psychology, physics or biology that do not explicitly test PK would nonetheless have had very different results if PK were real (i.e. if the wishes of the subject could physically alter the apparatus), so they should be interpreted as negative results.
- Lack of empirical progress: Humphrey highlights the paucity of positive results from two centuries of research:
- “While other sciences have clothed themselves in glory, parapsychology has lost even the undergarments that it started with. Not only have researchers failed to discover significant new facts, but by nagging away at the few facts they had thought were already in the bag they have slowly but surely taken away the credibility even from those.” –Soul Searching, page 142
- Argument from lack of information: It may be physically possible to bring about an intended effect, such as making a die fall a certain way, by applying certain forces to it. However, information about the exact forces necessary is often not available to the subject and therefore not part of the subject’s desire. Hence there is a conceptual problem with the idea that desire can be translated directly into an outcome.
- Indiscernability of paranormal hypotheses: If someone states in advance the values output by a random number generator, this would not justify a conclusion of PK, because if we admit paranormal hypotheses, it might be that they are getting the values by precognition.
Benassi, Victor A.; Paul D. Sweeney, and Gregg E. Drevno (1979). “Mind over matter: Perceived success at psychokinesis“. Journal of Personality and Social Psychology 37 (8): 1377-1386. doi:10.1037/0022-35220.127.116.117. Retrieved on 16 November 2008.
Blackmore, Susan J. (1992). “Psychic Experiences: Psychic Illusions”. Skeptical Inquirer 16: 367-376.
Blackmore, Susan J.; Tom Trościanko (1985). “Belief in the paranormal Probability judgements, illusory control, and the “chance baseline shift.”“. British Journal of Psychology 76 (4): 459-468. Retrieved on 16 November 2008.
Bösch, Holger; Fiona Steinkamp, Emil Boller (July 2006). “Examining psychokinesis: The interaction of human intention with random number generators–A meta-analysis”. Psychological Bulletin 132 (4): 497-523. doi:10.1037/0033-2909.132.4.497.
Humphrey, Nicholas K. (1995). Soul Searching: Human nature and supernatural belief. Chatto & Windus. ISBN 0-7011-5963-4.