The Harvard Group Scale of Hypnotic Susceptibility: accuracy of self-report and the memory for items.

Whereas early studies have found moderately high agreement between self- and observer-rated scores on the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A), these studies shared a common confound in that participants were aware of being directly observed. In the present study, confederates made surreptitious observations of group participants' hypnotic responding. Following the hypnotic procedure, participants indicated whether or not they remembered each item and provided self-reports of their hypnotic response. The study assesses the accuracy of participant self-report for hypnosis items when individuals are unaware of being observed. Thirty-two percent of participants failed to recognize at least one item from the hypnosis session, suggesting that the inability to remember items is a common phenomenon. When participants reported not remembering an item, the accuracy of their self-reported response was no better than chance.