Suggestibility in Legal Contexts

Psychological Research and Forensic Implications

Anne M. Ridley, Fiona Gabbert, David J. La Rooy

• Publisher: Wiley-Blackwell
• Year: 2012
• ISBN:
  9781118432822
• Edition: 1
• Topic: Psychology
• Subtopic: Forensic Psychology
• Index: Psychology

A comprehensive survey of the theory, research and forensic implications related to suggestibility in legal contexts that includes the latest research.

• Provides a useful digest for academics and a trusted text for students of forensic and applied psychology
• A vital resource for legal practitioners who need to familiarize themselves with the subject
• Includes practical suggestions for minimizing witness suggestibility in interviews
• Features topics that focus on suggestibility at each stage - from witnessing a crime through to trial

1

Suggestibility: A History and Introduction

ANNE M. RIDLEY

KEY POINTS

This chapter will provide an overview of the conceptual and historical factors that have contributed to modern research and theories of ­suggestibility in legal contexts:

• Definitions of suggestibility.
• Early work to establish whether suggestibility was one or more phenomena.
• Eyewitness testimony in the early twentieth century.
• Suggestibility in the early twentieth century.
• Cognitive and social theories relevant to suggestibility.

The 1970s and early 1980s heralded a new era in the study of ­suggestibility in legal contexts, an area that had been largely neglected since the early twentieth century. Using experimental studies, Elizabeth Loftus in the USA demonstrated how easy it was, under ­certain ­circumstances, to mislead people into remembering incorrect details about a witnessed event (Loftus, Miller, & Burns, 1978). Loftus’s was an experimental approach. In Europe, through his clinical and forensic work, Gisli Gudjonsson noted that some individuals seemed to be more ­suggestible than others. This approach assumed that ­suggestibility is a trait and led to the development of a model of ­interrogative ­suggestibility (Gudjonsson & Clark, 1986). Much research and debate have followed to establish whether suggestibility is a trait (i.e. some people are ­­inherently more suggestible than others), or whether suggestibility is merely the result of situational factors that can be manipulated ­experimentally. Nevertheless, what both approaches have in common is the fact that they consider ­suggestibility from the point of view of its impact on the accuracy of information obtained during the ­investigation of crimes, and that is the focus of this book.

The notion of interrogative suggestibility was originally proposed by Binet (1900) and has been used since by others, particularly Gudjonsson (e.g. Gudjonsson 2003; Gudjonsson & Clark, 1986). Recent use of the term interrogative suggestibility is usually restricted to suggestibility that occurs in the presence of inappropriate questioning plus pressure, either in the form of negative feedback and/or coercive interview ­techniques. If suggestibility is indeed a trait (and the evidence is ­equivocal: see Baxter, 1990, for a review), then it is one that is most likely to emerge when such situational pressures are present. Nevertheless, it is also possible for individuals to be suggestible simply through exposure to incorrect information about a previously ­witnessed event, or in response to leading questions, in an otherwise supportive evidence-gathering interview. We would argue that the term inves­tigative suggestibility should be used to distinguish ­suggestibility that occurs incidentally in this way from suggestibility that occurs due to interrogative pressure, and will therefore use these two terms, when appropriate in this book.

WHAT IS SUGGESTIBILITY?

Suggestibility is ‘a peculiar state of mind which is favourable to ­suggestion.’ (Sidis, 1898, p. 15)

Definitions of suggestibility and suggestion are many and varied, ­reflecting the difficulty in pinning down this pervasive yet ­perplexing aspect of human behaviour. Marcuse (1976, cited in Wagstaff, 1991) describes suggestibility in situational terms including ‘the influence of one person on another without his or her consent, the implanting of an idea, possessing a submissive tendency, and appealing to the ­unconscious’ (p. 132). In a similar vein, Stern (1910, p. 273), while ­talking of the psychology of testimony, defines suggestion from the ­influenced individual’s viewpoint as ‘the imitative assumption of a ­mental attitude under the illusion of assuming it spontaneously’. This latter definition is rather more suggestibility than suggestion, a ­distinction that was perhaps lost in translation from the German original.

Suggestion and suggestibility are linked but distinct concepts, with the latter generally resulting from the former. “Suggestion” refers to a type of influential communication, while “suggestibility” refers to the individual differences between those responding to suggestion under comparable circumstances’ (Hilgard, 1991, p. 37), a distinction ­elegantly captured by Sidis’s (1898) much earlier definition highlighted above. Thus, suggestion, whether in the context of hypnosis, social influence or incorrect information, can lead to a state or moment of suggestibility. In forensic psychology, suggestibility has been described in ­psychosocial terms as ‘the extent to which, within a closed social interaction, people come to accept messages communicated during formal questioning, as the result of which their subsequent behavioural response is affected’ (Gudjonsson & Clark, 1986, p. 84). In distinct contrast to the preceding definitions, Powers, Andriks, and Loftus (1979) define suggestibility in terms of memory processes, stating that it is ‘the extent to which they [people] come to accept a piece of post-event information and ­incorporate it into their recollection’ (p. 339). Whether suggestion has an impact on memory rather than behaviour, mirrors the situational versus trait approaches to suggestibility that have been the subject of sometimes strong debate since the 1980s.

IS SUGGESTIBILITY ONE CONSTRUCT OR MORE?

As illustrated in the above sections, suggestibility is hard to pin down. Many researchers have pointed out over the past century or so that there is no unitary concept of suggestibility and that the one word is used to describe a variety of phenomena (e.g. Binet, 1900; Eysenck, 1989; Wagstaff, 1991). In an attempt to resolve the issue, Eysenck (1947) proposed three types of suggestibility: primary, secondary and tertiary.

Primary suggestibility describes an ideo-motor phenomenon whereby thinking about or imagining one’s body moving can cause it to occur. This has been demonstrated experimentally in the body sway test (see Box 1.1), arm lowering, and pendulum tests. Primary suggestibility correlates highly with hypnotizability and neuroticism. In contrast, secondary suggestibility is linked to indirect suggestions where the purpose of the suggestion is not clear. It is not related to ­hypnotizability and is negatively related to intelligence. In other words, people who are ‘gullible’ (Eysenck & Furneaux, 1945) tend to be more suggestible.

Studies carried out since those by Eysenck and his colleagues have supported the notion of primary suggestibility (e.g. Duke, 1964; Evans, 1966, cited in Evans, 1967; Stukat, 1958), but this is not the case for ­secondary suggestibility. Evans (1967) questioned the methodology of Eysenck and Furneaux (1945). He re-evaluated the data and found that the notion of secondary suggestibility could not be justified. Evans ­concluded that three types of suggestibility could be identified: ‘­primary’ (passive motor), ‘challenge’,¹ and ‘imagery’ (sensory) ­suggestibility (p. 127). As they involve physical movement, primary and challenge suggestibility are of little relevance to investigative suggestibility. Imagery is more promising, and its relationship with investigative suggestibility has since been researched (see Eisen, Winograd, & Qin, 2002, for a review).

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Box 1.1 Eysenck & Furneaux (1945), Primary and Secondary Suggestibility

Eysenck and Furneaux raised the question of whether suggestibility is a single mental trait or a number of separate ‘suggestibilities’ (p. 485). They carried out a study among 60 neurotic patients in an army ­hospital. A battery of 12 different tests was administered in order to understand the relationships between them and whether they would support the notions of primary and secondary suggestibility.

Examples of tests given and the type of suggestibility it was hypothesized that they related to:

Picture Report (secondary): A picture was studied for 30 seconds, followed by 14 questions about it, of which five contained incorrect details. Suggestibility was measured by the number of suggested details accepted.

Ink Blot Suggestion Test (secondary): Typical responses to Rorschach ink blots were suggested as well as implausible responses. Suggestibility was measured by the number of implausible ­suggestions accepted.

Body Sway Test (primary): Participants closed their eyes and it was suggested they were falling forward. The amount of sway was measured via a thread attached to the participants’ clothing. ‘Complete falls are arbitrarily scored as 12 inches’ (p. 487).

Odour Suggestion Test (secondary): Participants were asked to ­identify the scents presented in different bottles. The three final ­bottles presented contained water. Suggestibility was measured by the number of these placebo bottles that had an odour attributed to them.

Hypnosis (primary): Attempted induction was via ‘fixation of a bright object, a constant low sound, and verbal suggestion’ (p. 488). Various suggestions were made to participants such as tiredness and hallucinations. A total hypnosis score was derived from responses to the suggestions.

Analysis supported the two types of suggestibility, although more so for primary than for secondary suggestibility. The best tests of primary suggestibility were the body sway test and hypnosis, while the ink blot and odour tests were the best tests of secondary suggestibility.

Of particular relevance to suggestibility in legal contexts is the picture report test, which used a method very similar to that since adopted in studies of investigative suggestibility. The suggestibility effect was relatively small with a mean of 1.0 (SD 1.1) out of a ­possible 5.0, and the picture report test did not map strongly onto the concept of secondary suggestibility.

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Eysenck (1947) also proposed a third or ‘tertiary’ type of ­suggestibility. He linked this to attitude change and persuasion, emphasizing the importance of interpersonal factors such as the perceived authority of the person providing the suggestion. Although Evans (1967) concluded that there was little evidence of this effect, more recent research in the area of suggestibility in legal contexts indicates otherwise, to the extent that there is now an acknowledged link between interrogative ­suggestibility and tertiary suggestibility (Eysenck, 1989; Sheehan, 1989). Furthermore, Sheehan (1989) proposed that Gudjonsson’s ­suggestibility scales are a form of indirect suggestion. The term ‘­indirect’ links back to secondary suggestibility. Thus it can be argued that interrogative suggestibility may bridge two of Eysenck’s ­categories of suggestibility: secondary and tertiary.

THE HISTORY OF SUGGESTIBILITY RESEARCH

Hypnosis and Suggestibility

As the previous section illustrates, the history of suggestibility is closely intertwined with that of hypnosis. The two have been linked by Orne (1977, cited in Gheorghiu, 1989, p. 4) who defined hypnosis as ‘the state in which suggestion can be used to give rise to distortions in perception and memory’.

Hypnosis is characterized by a relaxed and drowsy state, during which the influenced individual is responsive to suggestions made such as hallucinations or age-regression. A further characteristic of the state is that the person involved is subsequently able to report that he was hypnotized (Barber, Spanos, & Chaves, 1974), although amnesia for experiences during hypnosis sometimes occurs. This amnesia may either be suggested or may happen independently of a specific suggestion (Eysenck & Furneaux, 1945). Hypnosis is used widely in therapies of various kinds, from psychological distress through to treatment of addiction and relief of pain. Such therapy has sometimes resulted in recovered memories of childhood sexual abuse, and hypnotism has also been used on occasions to obtain testimony in police investigations (see Orbach, Lamb, La Rooy, & Pipe, 2012, for an example).

The use of hypnosis has a long history, dating back at least as far as de Montagne in the seventeenth century and Franz Mesmer in the eighteenth century. Mesmer believed the effects observed when he mesmerized or hypnotized his patients were due to animal magnetism; an external life force that was a result of his connection to the patient. He disagreed with de Montagne, who proposed that the imagination of the patient was the primary cause. With hindsight it would seem that de Montagne was closer to the mark. The study of hypnotism continued through the work of Freud, Janet and Binet among others, although it was probably Bernheim (1888/1964) who first linked hypnosis to ­suggestibility. He proposed that the former was a heightened state of the latter. Modern researchers do not agree with this position due, in part, to the circular nature of the theory (suggestibility leads to ­hypnosis leads to suggestibility), although it is generally accepted that the two phenomena are closely linked. According to Edmonston (1989):

… although suggestion may be a route for establishing the condition of hypnosis, we should agree that hypnosis is not suggestion and suggestion is not hypnosis, and that to study one is not necessarily to study the...

Table of contents

• Cover
• Series page
• Title page
• Copyright page
• Dedication
• Contributors
• Series Preface
• Preface
• Acknowledgements
• 1 Suggestibility: A History and Introduction
• 2 The Misinformation Effect: Past Research and Recent Advances
• 3 Interrogative Suggestibility and Compliance
• 4 Suggestibility and Memory Conformity
• 5 Suggestibility and Individual Differences: Psychosocial and Memory Measures
• 6 Recovered Memories and Suggestibility for Entire Events
• 7 Suggestibility and Individual Differences in Typically Developing and Intellectually Disabled Children*
• 8 Suggestibility in Vulnerable Groups: Witnesses with Intellectual Disability, Autism Spectrum Disorder, and Older People
• 9 Acute Suggestibility in Police Interrogation: Self-regulation Failure as a Primary Mechanism of Vulnerability
• 10 Suggestibility and Witness Interviewing using the Cognitive Interview and NICHD Protocol
• 11 Suggestibility in Legal Contexts: What Do We Know?
• Index