Hypnosis and the relationship between trance, suggestion, expectancy and depth: some semantic and conceptual issues.

A commentary discusses two papers by Pekala and colleagues that examine relationships among trance or altered state effects, suggestibility, expectancy, hypnosis, and hypnotism. The first paper reviews these concepts and introduces the PCI-HAP assessment instrument. The second empirically tests whether these concepts predict hypnotic depth scores, concluding that multiple processes are involved in hypnotism, while hypnosis itself consists only of altered state or trance effects. The commentary raises methodological, semantic, and conceptual issues, arguing that many problems in defining hypnosis-related terms could be clarified by historical context. It suggests difficulties in identifying origins of hypnotic experiences may stem from insufficient attention to suggestion and expectancies and over-reliance on induction procedures.

Study at a glance

Abstract

In the first of two recent papers, Pekala, Kumar, Maurer, Elliot-Carter, Moon and Mullen (2010a) review what they consider to be the relationships between trance or altered state effects, suggestibility, and expectancy, and how they relate to the concepts of hypnosis and hypnotism. They also suggest that these concepts can be assessed with an instrument they term the PCI-HAP (Phenomenology of Consciousness: Inventory-Hypnotic Assessment Procedure). In the second paper (Pekala, Kumar, Elliot-Carter, Moon, & Mullen, 2010b), they set out to determine empirically whether these concepts can predict hypnotic depth scores using the PCI-HAP. They conclude that their results support the view that all of these component processes may be involved in 'hypnotism' and experiences of hypnotic depth. However, according to their conceptualization, 'hypnosis' itself involves, or consists of, only altered state or trance effects. These papers raise a number of fundamental methodological, semantic and conceptual issues that are discussed in this commentary. Topics discussed include distinctions between concepts such as 'hypnosis', and 'hypnotism,' the role of inductions and suggestion in producing hypnotic phenomena, and the measurement and conceptualization of 'hypnotic depth.' It is concluded that many of the problems relating to the definition and conceptualization of terms associated with hypnosis may be clarified by placing the terms in their historical context, and that difficulties in identifying the origins of the experiences and behaviours associated with hypnosis may stem from insufficient attention to the role of suggestion and expectancies in producing hypnotic phenomena, and an over-reliance on the role of the procedures and mechanics of the induction process.