Subjects
A priori power analysis performed by G*Power3.1 (Faul et al., 2009) for
repeated measures ANOVA indicated that for the expected
η2 = 0.3 (Pollatos et al., 2005) and α = .05 the
sample size of 16 participants for each group would be enough to achieve
power = 0.89. After the approval by the Bioethics Committee of the
University of Pisa (n.17/2021), participants of both sexes were
recruited among the right-handed (Edinburgh Handedness Inventory, score> 16) students at the University of Pisa who had
undergone hypnotic assessment through the Italian version of the
Stanford Hypnotic Susceptibility Scale, form A (SHSS, A (range: 0-12),
Weitzenhoffer & Hilgard, 1959,) in the latest 6 months. Details
regarding hypnotizability SHSS scales are available in Sheehan and
McConkey (1981). After their written informed consent, 16 highs (SHSS
score (mean + sd): 10.18 + 1.19; 9 females, age: 25.14+ 3.82 yrs) and 16 lows (SHSS score: 0.20 + .56; 7
females, age: 26.47 + 4.82 yrs) with medical, neurological and
psychiatric negative anamnesis, no attention /sleep disturbance and
drugs intake in the latest 6 months were enrolled. The final group was
composed of 16 highs and 15 lows because one of the male lows was
excluded from analyses owing to technical problems in the ECG recording.
The two groups were homogeneous for education (master’s students). Six
highs and 3 lows reported basic experience of meditation. Medium
hypnotizable individuals (mediums) were not enrolled to maximize the
effects of hypnotizability on the studied variables during hypnosis (De
Pascalis et al., 2000; Elkins et al., 2015).