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Article Excerpt
Psychics and mediums claim to possess a diverse range of paranormal powers, including, for example, the ability to predict the future, communicate with the dead, and read minds (Wiseman & Morris, 1995a). One of the most controversial claims is that of psychokinetic metal bending (PKMB)--the alleged ability to deform metallic objects, such as keys and cutlery, by thought alone. In a typical PKMB demonstration, a metal object appears to bend whilst being gently held by an alleged psychic. Psychologists, parapsychologists, and magicians have all explored ways in which such demonstrations can be duplicated by trickery. Each group has approached the issue from a slightly different perspective, with psychologists focusing on the potential of such work to inform the psychology of deception (Marks & Kammann, 1980), parapsychologists concentrating more on its importance for assessing allegedly genuine demonstrations of PKMB (Hansen, 1990; Morris, 1986; Randi, 1983a, 1983b; Truzzi, 1987), and magicians examining how such work can help enhance their performances (Fuller, 1975; Harris, 1985).
The resulting literature has explored a wide variety of possible methods for faking PKMB, including, for example, the switching of straight objects for pre-bent duplicates, the concealed application of force, and ways of secretly inducing metallic fractures (see, e.g. Fuller, 1975; Harris, 1985; Marks & Kammann, 1980; Randi, 1975). However, these types of methods do not account for an intriguing aspect of alleged PKMB that has come to be referred to as the 'after effect'. In a typical PKMB demonstration, the alleged psychic apparently uses his or her paranormal abilities to deform an object. In some demonstrations the alleged psychic then produces an after effect, wherein the object is placed on a table but apparently still continues to bend by a small but noticeable amount (see, e.g. Hasted, 1981; Marks & Kammann, 1980). Although some researchers have expressed scepticism about the evidential status of this type of testimony (see, e.g. Hansen, 1990; Hodgson & Davey, 1887; West, 1982), others believe that such effects cannot be the result of trickery because the alleged psychic is no longer in contact with the object, and therefore view eyewitness reports of this phenomenon as strong evidence for the paranormal (see, e.g. Panati, 1976). In contrast, sceptics and magicians have argued that such effects could be created by verbal suggestion. For example, in a book devoted to methods for faking alleged PKMB, magician Ben Harris (1985) noted:
If you are doing a really convincing job, then you should be able to put a bent key on the table and comment, 'Look, it is still bending', and have your spectators really believe that it is. This may sound the height of boldness; however, the effect is astounding--and combined with suggestion, it does work (p. 46).
As a result of such speculations, some psychologists have argued that testimony describing apparent PKMB after effects is not evidential of genuine psychic ability (see, e.g. Marks, 2000).
The idea that PKMB after effects can be created by verbal suggestion has not been subjected to any form of systematic evaluation or investigation. This is unfortunate for two main reasons. First, from a psychological perspective, such research has the potential to help inform our understanding of suggestion. Most laboratory research into verbal suggestion involves participants being shown information about a relatively commonplace event (e.g. slides or a videotape of a minor car accident), receiving incorrect information about what they have just witnessed, and then being tested on their recollection of stimuli material (see, e.g. Loftus, 1997; Loftus, 1992; Roediger, Wheeler, & Rajaram, 1993). However, very little research has examined the effects of verbal suggestion on the perception of an ongoing event, or events that are as unusual as alleged PKMB. As such, the results of such work could play an important role in expanding our understanding of the potential relationship between verbal suggestion, observation and recall. Second, from a parapsychological perspective, such work could help evaluate the reliability of testimony for alleged PKMB after effects, and therefore the degree to which such testimony constitutes evidence for the paranormal. This paper addresses these issues by describing two studies that explored whether it is possible to create testimony for PKMB after effects via verbal suggestion alone.
In the first experiment, participants were shown a videotape of an apparent PKMB demonstration. During the videotape a performer stroked the stem of a key and revealed that this had apparently caused the stem to develop a very noticeable bend. He then placed the key on the table. Participants in the suggestion condition then heard the performer suggest that the key was continuing to bend. In contrast, participants in the no-suggestion condition saw exactly the same footage but did not hear this suggestion. Participants were then asked whether the key had continued to bend whilst it lay on the table. It was predicted that those who heard the suggestion would be significantly more likely to report that the key had continued to bend.
The study also investigated the role that participants' belief in the paranormal may play in mediating such effects. Psychologists have carried out a considerable amount of work into the psychology of paranormal belief (see, e.g. reviews by French, 1992; Irwin, 1999, 1993), with some researchers reporting a positive relationship between such beliefs and several different measures of suggestibility (Haraldsson, 1985; Wiseman, Greening, & Smith, 2003). The experiments reported here extended this work by examining the possible relationship between paranormal belief and verbal suggestibility within the context of PKMB after effects. Prior to seeing the videotape, participants completed a questionnaire about their belief in the paranormal, and it was predicted that participants who tended...
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