Caffeine and Stress Promote a More Liberal Bias on Tasks Assessing Hallucination-Like Experiences and False Memory in a Nonclinical Sample

A Systematic Review of the experimental induction of auditory perceptual experiences

BACKGROUND AND OBJECTIVES

Voice-hearing exists on a continuum and research studies have utilised experimental paradigms in an attempt to induce unusual auditory experiences in clinical and non-clinical samples. The aim of the current review was to systematically identify, review and appraise voice-hearing induction paradigms in order to guide researchers.

METHODS

Five databases were searched for studies in which an experimental manipulation was used with the aim of inducing an auditory experience akin to voice-hearing. Papers were assessed for quality and the voice-hearing paradigms critically appraised.

RESULTS

Forty-nine studies, included in 41 papers, were reviewed. Studies were organised into five groups based on the type of voice-hearing paradigm used: sensory deprivation/limitation; hallucination suggestion; combined suggestion and ambiguous stimulus; signal detection and voice detection tasks; and auditory discrimination/transformation. Signal and voice detection tasks were found to be the most robust paradigms. The quality of paradigms was assessed, and their strengths and limitations evaluated, including evidence in relation to their utility, ecological validity and usability.

LIMITATIONS

The current review excluded case studies, grey literature and studies which were not written in the English language, and as such voice-hearing paradigms may have been missed.

CONCLUSIONS

Voice-hearing paradigms vary in their ecological validity and experimental robustness. A challenge for future research is to develop a paradigm in which internally generated material can be attributed externally in a way that more closely represents inner speech and the experience of voice-hearing.