Hypnotic susceptibility and the endogenous eyeblink: a brief communication.

This study investigated the relationship between hypnotic susceptibility, hypnotic state, and the endogenous eyeblink with 36 undergraduates, who were assigned to four independent groups (waking-low, hypnotized-low, waking-high, and hypnotized-high susceptibles) on the basis of combined cutoff scores on both the Creative Imagination Scale and the Stanford Hypnotic Clinical Scale for Adults. The auditory vigilance task required subjects to discriminate between 200 ms and 300 ms tones over a 35-minute period. Hypnotic depth was controlled across trials using the Long Stanford Scale of Hypnotic Depth. As predicted, high-susceptible subjects had a significantly lower blink rate than low-susceptible subjects. The predicted interaction between susceptibility and hypnotic state was also confirmed. High-susceptible subjects showed a significant decrease in blinking for the hypnotized condition, whereas low-susceptible subjects did not. The need for replication with more adequate measures of susceptibility is discussed.