Hypnotic susceptibility scales: Are the mean scores increasing?

Abstract

The Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C), developed and named 37 years ago, is arguably the "gold standard" of hypnotic susceptibility scales. However, it has been the impression of several researchers that means obtained on the SHSS:C are higher now than in previous years. The authors comprehensively review studies using the SHSS:C over a 4-decade period. The findings demonstrate a significant linear trend between year and SHSS:C scores, with higher obtained means in more recent work. The authors also report a similar analysis of research with the Harvard Group Scale of Hypnotic Susceptibility, Form A. Although the mechanisms underlying this trend can only be speculated upon at present, these findings underscore the importance of using local control groups in research on hypnotizability.

Hungarian Norms for the Harvard Group Scale of Hypnotic Susceptibility, Form A

“…Benham, Smith, and Nash (2002) detected in their betweenlab examination that standard hypnotizability scores exhibit a statistically significant and continuous increase since the 1960s. Our analysis, carried out on aggregated HGSHS:A, SHSS:A, and SHSS:B data collected in our laboratory from 1973 to 2010, supported the notion that hypnotizability scores are increasing over time (Költő, Gősi-Greguss, Varga, & Bányai, 2014).…”

Recalled Parental Rearing Style and Dimensions of Hypnotic Response

“…Second, the data collection (especially in Sample 1) happened a relatively long time ago. Hypnotizability scores show a general increase over time (Benham, Smith, & Nash, 2002;Költő et al, 2014), and the 8 years since data for Sample 1 were collected can make a difference. The number of adolescents who report their parents being supportive also shows an increase in many countries during an 8-year period, although no remarkable trend was observed in Hungary (Brooks et al, 2015).…”

Polish Norms for the Harvard Group Scale of Hypnotic Susceptibility, Form A

“…Recent analysis of the contents of the International Journal of Clinical and Experimental Hypnosis (IJCEH) done by the present author revealed that during the last decade (between 1999 and 2008), the scale was used in 49.3% (i.e., in 68 out of 138) of all experiments reported. Benham, Smith, and Nash (2000) also report that the HGSHS:A is probably the most widely used measure of hypnotizability. It is thus clear that the HGSHS:A continues to be the most popular instrument to measure hypnotic susceptibility, by far exceeding other measures such as the Barber Suggestibility Scale 434 JERZY SIUTA (BSS; Barber,1965), the Hypnotic Induction Profile (HIP; Spiegel, 1972), the Carleton University Responsiveness to Suggestion Scale (CURSS; Spanos et al, 1983), and the Waterloo-Stanford Group C (WSGC) Scale of Hypnotic Susceptibility (Bowers, 1993).…”