Base rate expectancies and motoric alterations in hypnosis

Abstract

Degree of responsiveness to “suggestion” in an experiment which did not utilize hypnotic induction (the Berkeley Sample) was comparable to that obtained in an experiment which did utilize hypnotic induction (the Stanford Sample). Procedural differences between the 2 experiments—self-scoring vs. objective-scoring, and group vs. individual testing—were regarded as not crucial in making a comparison of the 2 experiments. The distribution of responses in the Berkeley Sample may be taken as the base rate. The slightly higher degree of responsiveness over the base rate in the Stanford Sample (on some tests) may be attributed to the “degree of volunteering” that characterized the sample. The importance for experiments in the future to create equal levels of motivation and expectation to perform well under both the hypnotic and the nonhypnotic conditions is stressed, and brief mention is made of a new metaphor to be used in the conceptualization of the problems of hypnosis.