New Voices: The power of suggestion

An entire industry has arisen from the idea that through the power of suggestion we can change and improve our lives. Books, magazines and TV programmes all offer ways in which self-hypnosis and the power of 'positive thought' can help us to give up smoking, bolster our careers and improve love lives. Unfortunately the evidence is largely anecdotal and subjective, but there is considerable scientific support for the power of suggestion within a therapeutic setting, with Henderson (2003, p.170) claiming: 'The effectiveness of suggestion has been demonstrated over and over again in every field of medicine and human behavior. In fact, in practically every instance of research on drugs with humans, suggestion has been proven effective. In many cases it was more effective than the pharmaceutical being tested!'

The notion of 'suggestibility' is of interest to psychologists from all corners of the discipline, as it encompasses a wide variety of areas relating to cognitive, social and personality factors. Here we look at suggestibility in a range of contexts, to consider whether suggestibility is a personality trait or a cognitive bias, and who will be susceptible.

The power of placebo

Simply believing that something is doing you good can in fact make a positive difference. In many clinical drug trials, a sizeable minority of people will show a measurable, observable or felt improvement in their condition having taken nothing more than an inert placebo. Charron et al. (2006), for example, showed the power of placebos for patients suffering from back pain, and similar results have been shown with response to the discomfort of irritable bowel syndrome (e.g. Conboy et al., 2006), and in assessing the effects of homeopathy (e.g. Walach et al., 2005). The effects can be large: Kirsch and Sapirstein (1998) conducted a meta-analysis of some 39 studies on the effectiveness of Prozac with patients suffering from depression, and concluded that placebos could account for over 50 per cent of reported improvements in the condition. The precise mechanism by which the placebo effect works is not known, but it is clear that the belief that something works can have a powerful psychological effect.

Distortions of memory

Most of the research that has looked at the nature of suggestion has focused on its impact on memory. Elizabeth Loftus, for example, has demonstrated how leading questions and suggestive information can seriously distort a person's memory for an observed event (e.g. Loftus, 1979).

The pernicious effect of suggestive procedures has also been explored in relation to the creation of false memories within therapy. Years of empirical research suggest that false memories of childhood sexual abuse (satanic or non-satanic), reports of alien abduction and vivid tales of past lives, often share a common feature. In many cases these fantasy-based 'memories' have come about in response to hypnotic or other suggestive procedures carried out by therapists and misguided enthusiasts. However, it is also likely that the client's own pre-existing beliefs may be sufficient to generate false memories even in the absence of explicit suggestions from the therapist.

Suggestive techniques have also been critically examined within a forensic setting and, in particular, in the way that suspects and witnesses are questioned by police and investigators. Interrogative suggestibility is 'the extent to which, within a closed social interaction, people come to accept messages communicated during formal questioning, as a result of which their subsequent behavioural response is affected' (Gudjonsson, 1987, p.215). Bruck and Ceci (1996) report interrogative suggestibility can occur because of certain personal characteristics or in particular situations. Also, interrogative suggestibility depends upon the degree of interviewer bias and the pressures they may exert on the interviewee, thus contaminating the memory of the individual.

One well-documented and vivid example of the egregious power of suggestive questioning involves the case of Paul Ingram (Wright, 1994). In 1988 Ingram's daughter accused her father of child abuse and Paul Ingram was subsequently brought in for questioning by the local police. Initially, he claimed to have no memories whatsoever, but during the interrogation Ingram was repeatedly told that he must have committed the crimes, and was urged to imagine the alleged events. Eventually, Ingram provided the police with confessions of increasingly bizarre acts. Richard Ofshe, a psychologist, was asked to assess Ingram and subsequently provided evidence in the case. He went to see Ingram in jail and suggested a completely fabricated story of incidents and criminal acts that Ingram had allegedly carried out on family members. Ofshe instructed Ingram to pray on the idea, and he was then able to come up with completely fabricated accounts of the crimes suggested to him. Despite this, Ingram was convicted on multiple charges and spent many years in prison but was finally released in 2003.

It seems almost impossible to believe that someone would confess to such a heinous crime that they did not commit, yet similar stories of the effects of suggestive techniques have been demonstrated in other cases of false confession. Kassin (1997) has shown how certain individuals faced with gruelling and emotionally damaging police interrogations have confessed to appalling crimes and in some cases have even come to believe that they were in some way guilty.

Suggestion – It's magic!

For many years, magicians have been exploiting our vulnerability to suggestion for centuries in order to achieve all kinds of illusions and sleight of hand tricks. One of the basic tools used by magicians is the practice of misdirection, which is made possible because of the power of suggestion. For example, when verbal suggestion has succeeded in diverting the attention of the audience, the trained magician is then able to substitute or remove objects. Interestingly, many conjurers claim that it is much easier to fool a room full of scientists than a classroom of children, since the scientific mind will look for cause and effect whereas children, on the other hand, are more likely to rely on their observation (Gaddis, 2004).

Suggestion and the paranormal

As with magicians, the use of suggestion is a powerful tool with which to convince credulous audiences. Many sceptics have written on the subject of trickery and chicanery involved in demonstrations of allegedly paranormal abilities by psychics and mediums (e.g. Randi, 1980; Wilson, 2006). However, the use of verbal suggestion in pseudo-psychic demonstrations has not been scientifically explored until recently.

Wiseman et al. (2003) describe two experiments in which they examined suggestion in the séance room, asking whether prior belief in the paranormal made participants more prone to suggestion in this context. In their first experiment, around a third of the witnesses erroneously reported that a stationary table had moved during the séance following a suggestion from the fake medium to this effect. Believers in the paranormal were more likely to misreport such movement than disbelievers. Believers were shown to be more susceptible to suggestion than disbelievers in a second set of fake séances too, but only when the suggestion was congruent with their belief in the paranormal. For example, if the fake medium suggested that an object had not moved when in fact it had (by trickery), believers were no more likely to accept the suggestion than disbelievers. Overall, around one fifth of the participants believed they had witnessed genuine paranormal phenomena. As Wiseman and colleagues point out, it is unclear whether the verbal suggestion directly affected the participants' perception of the event, their memory of the event, or both. It is even possible that neither perception nor memory was affected and that the results were due to demand characteristics, but the end result is the same: a large minority of the participants were willing to report that stationary objects had moved and that they had witnessed genuinely paranormal events.

The role of individual differences

Given the variety of instances in which suggestion can have an impact on our lives and behaviour, it might be fair to propose that our vulnerability to suggestion might be all too common a part of what it is to be human. Gaddis (2004, p.4), for example, says: 'It is a psychological fact that the first impulse of people is to believe. Doubting is usually secondary. And the power of suggestion wields a tremendous influence on our lives and opinions.'

A considerable amount of research has explored a range of individual differences that might correlate with suggestibility. For example, a person's intelligence has an effect on whether or not he or she is suggestible in interrogation situations. Those with an average or above-average level of intelligence and cognitive ability will most likely be able to assess whether information may be misleading (Boon & Baxter, 2004). In addition to intelligence, one study found highly acquiescent individuals to be more open to suggestive questions and pressure from experimenters. Also, those with low competence esteem, which is seen as low effectiveness in achievement situations, are susceptible to suggestive questioning and negative feedback from interrogators because they may doubt their own opinions, thus believing the misleading information to be a more reliable source (Peiffer & Trull, 2000). Interestingly, Peiffer and Trull (2000) only tested female participants, their rationale being that previous studies had found gender differences in suggestibility (e.g. Loftus et al., 1991). However, the findings remain inconclusive on this issue.

It is clear, then, that many of us are susceptible to various kinds of suggestion, be it from trusted others, authority figures, self-help books or researchers investigating memory effects. What is perhaps less clear is why we are so susceptible and what might be the mechanisms behind suggestibility. Perhaps I could suggest that this area is ripe for research.

Dr Krissy Wilson is a lecturer at Charles Stuart University, Australia

References

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Wright, L. (1994). Remembering Satan. New York: Knopf.