hypnosis

What Is Hypnosis in the Polygraph Context?

Hypnosis is an altered state of consciousness characterised by heightened suggestibility, focused attention, and reduced peripheral awareness. In polygraph science, hypnosis has been studied both as a potential mental countermeasure that examinees might use to suppress physiological responses and as a potential forensic interview technique that might affect subsequent polygraph testing.

As a Countermeasure

Research has investigated whether hypnotic suggestion can suppress the physiological responses that the polygraph measures. Findings suggest that while hypnosis can produce some reduction in general arousal, its effectiveness as a polygraph countermeasure is limited — particularly in CQT formats where differential responsivity persists even with overall arousal reduction. Self-hypnosis, like other relaxation-based countermeasures, tends to suppress all responses proportionally rather than selectively eliminating deception-related responses.

Impact on Memory and Testing

Hypnotically refreshed memories raise concerns for polygraph testing because they may create false confidence in inaccurate recollections. An examinee who has undergone hypnosis for "memory recovery" may genuinely believe confabulated memories, complicating the assessment of truthfulness. Many jurisdictions restrict the use of hypnosis in forensic contexts for this reason. Examiners should inquire about prior hypnosis during the pre-test interview.

Practical Application

Understanding this concept contributes to the comprehensive knowledge base required for competent polygraph practice. The APA Standards of Practice and Code of Ethics require that examiners maintain the theoretical and practical knowledge necessary to conduct examinations competently, interpret data accurately, and communicate findings clearly in examination reports and, when required, in legal proceedings.