The Sussex-Waterloo Scale of Hypnotizability (SWASH): measuring capacity for altering conscious experience

Abstract

The ability to respond to hypnotic suggestibility (hypnotizability) is a stable trait which can be measured in a standardized procedure consisting of a hypnotic induction and a series of hypnotic suggestions. The SWASH is a 10-item adaptation of an established scale, the Waterloo-Stanford Group C Scale of Hypnotic Suggestibility (WSGC). Development of the SWASH was motivated by three distinct aims: to reduce required screening time, to provide an induction which more accurately reflects current theoretical understanding and to supplement the objective scoring with experiential scoring. Screening time was reduced by shortening the induction, removing two suggestions which may cause distress (dream and age regression) and by modifications which allow administration in lecture theatres, so that more participants can be screened simultaneously. Theoretical issues were addressed by removing references to sleep, absorption and eye fixation and closure. Data from 418 participants at the University of Sussex and the Lancaster University are presented, along with data from 66 participants who completed a retest screening. The subjective and objective scales were highly correlated. The subjective scale showed good reliability and objective scale reliability was comparable to the WSGC. The addition of subjective scale responses to the post-hypnotic suggestion (PHS) item suggested a high probability that responses to PHS are inflated in WSGC screening. The SWASH is an effective measure of hypnotizability, which reflects changes in conscious experience and presents practical and theoretical advantages over existing scales.

Demand Characteristics Confound the Rubber Hand Illusion

“…Given that implicit measures have often been developed with ownership in mind, this should not be surprising, even if the illusion is entirely a suggestion effect. Note that the discovery of substantial relationships between response to imaginative suggestion and the RHI considerably extends the range of effects with which RHI illusion reports would be likely to correlate, if experimental demand characteristics suggested them (e.g., paralysis, amnesia, hallucinations, involuntary movement, analgesia, etc; see Lush et al, 2018 for SWASH hypnotisability scale suggestions).…”

“…Despite this, response varies reliably for different types of suggestion (perhaps reflecting differing cognitive requirements; Woody & Barnier, 2008). For example, 77% of participants respond to a suggestion that their hands will be drawn together as though they were magnets, but only around 26% respond to auditory and tactile hallucination of a suggested mosquito (see Lush et al, 2018). Mean subjective report is consequently greater for the moving hands suggestion than for the mosquito suggestion, but this should not be interpreted as evidence there is a 'real' magnet effect which is not attributable to suggestion.…”

Strategies that reduce Stroop interference

“…Participants. We recruited 78 participants from which 57 (mean age = 19.61, SD = 1.47, females = 51) had been screened for hypnotisability with the Sussex-Waterloo Scale of Hypnotisability (SWASH; Lush, Moga, McLatchie & Dienes, 2018). As we specified in the pre-registration, we excluded the data of those who did not have a SWASH score from all of the analyses.…”

A critical review of standardized measures of hypnotic suggestibility

“…Further measurement advances include the development of scales that can be quickly administered in clinical and experimental contexts (Elkins, 2014;Lush et al, 2018;Pekala et al, 2010;Spiegel & Spiegel, 1978) or online (Palfi et al, 2019;Wieder & Terhune, 2019).…”