Hypnotic susceptibility

Hypnotic susceptibility is a measurement of how easily a person can be hypnotized. There are several types of scales used; however, the most common are the Harvard Group Scale of Hypnotic Susceptibility and the Stanford Hypnotic Susceptibility Scales. The Harvard Group Scale, as the name implies, is administered predominantly to large groups of people while the Stanford Hypnotic Susceptibility Scale is administered to individuals. No scale can be seen as completely reliable due to the nature of hypnosis. It has been argued that no person can be hypnotized if they do not want to be; therefore, a person who scores very low may not want to be hypnotized, making the test scores invalid.

Harvard Group Scale

Ronald Shor and Emily Carota Orne developed the Harvard Group Scale in 1962. It consists of 12 items of progressive difficulty (as defined, psychometrically, by the percentage of subjects in a normative sample that reports experiencing each particular item) and usually takes around forty-five minutes to complete. The items usually consist of motor tasks and cognitive tasks with the motor tasks being easier to complete. The average score is 5 out of 12. The test is self-scored leaving it open to criticism concerning the validity of the scores.

tanford Scale

The Stanford Scale was developed by Andre M. Weitzenhoffer and Ernest R. Hilgard in 1959. The Scale consists of three Forms: A, B, and C. Similar to the Harvard Group Scale, each Form consists of 12 items of progressive difficulty and usually takes fifty minutes to complete. Each form consists of motor and cognitive tasks but vary in their respective intended purpose. The administrator scores each form individually.

Form A

Based upon the scale developed by Joseph Friedlander and Theodore Sarbin (1938), this form was developed to measure susceptibility to hypnosis with items increasing in difficulty in order to yield a score. The higher the score, the more responsive one is to hypnosis. Following a standardized hypnotic induction, the hypnotized individual is given suggestions pertaining to the list below.

Form B

Form B was designed to be used as a follow-up to Form A when doing experiments involving a second session of hypnosis. The items are similar but are changed somewhat (e.g. the use of the opposite hand in a particular item). The changes were made to "prevent memory from the first exerting too great an influence upon the recall of specific tasks..". cite book |last= Weitzenhoffer & Hilgrad |first= |authorlink= |coauthors= |title= |year= 1959|publisher= |location= |isbn= ]

Form C

Created a few years after Forms A and B, Form C contains some items from Form B, but includes more difficult items for "when subjects are being selected for advanced tests in which knowledge of their capacity to experience more varied items is required" (pgs v-vi Weitzenhoffer & Hilgard 1962). Following a standardized hypnotic induction, the hypnotized individual is given suggestions pertaining to the list below.

In more modern experiments, a scent such as peppermint has been used in place of ammonia for Item 9.

Other scales

These tests are not widely used because they are usually seen as less reliable than the Stanford Scale and Harvard Group Scale. Many professionals think that these tests produce results because they involve concentration and a certain level of concentration is required to be hypnotized.

Hypnotic Induction Profile

The Hypnotic Induction Profile (HIP) [Stern, D.B., Speigel, H., & Nee, J.C. (1979) The Hypnotic Induction Profile:Normative observations, reliability, and validity. American Journal of Clinical Hypnosis, 21, 109-133 ] or the eye roll test, first proposed by Herb Spiegel, is a simple test to loosely determine if a person is susceptible to hypnosis. A person is asked to roll his or her eyes upward. The degree to which the iris and cornea are seen is measured. The less of this part of the eye observed, the more hypnotically susceptible a person is. Research has shown that the scale does not carry as strong a relationship with other hypnotic scales as originally thought, with correlations ranging from 0.1 to 0.15 (Orne et al. 1979).

Light test

Individuals are asked to stare at a small light in a dark room. Many people think the light is moving and those who see it change direction the most are thought to be suitable for hypnosis.

External links

* [http://ist-socrates.berkeley.edu/~kihlstrm/hypnosis_research.htm Examples of the Harvard Group Scale and the Stanford Scale]
* [http://www.hypnosisandsuggestion.org/measurement.html Measurement of suggestibility on HypnosisAndSuggestion.org]
* [http://www.hypnosisschool.org/9.php Suggestibility Profile]

References