In four-thousand years of hypnosis, we've only found one physical characteristic that shows a high correlation to the ability to be hypnotized.
In 1972, Dr. Herbert Spiegel, M.D. published "An Eye Roll Test for Hypnotizability" in the American Journal of Clinical Hypnosis, which detailed a method to determine trance capacity using the eyes. This test has been found to be accurate in more than 70% of cases.
In short, the subject is asked to roll their eyes back, much as if they were looking up through a hole in the hairline. The more the eyes roll up, the more susceptible the person is. The amount of roll is recorded on a scale of 0-4, with 4 being the most roll/most susceptibility to hypnosis.
You can read the complete paper here: "An Eye Roll Test for Hypnotizability - Dr. Herbert Spiegel, M.D."
Hypnotic Induction Profile
Administration of the HIP can be a routine part of the initial visit and evaluation. The test begins with the eye-roll sign, a presumptive measure of biological ability to experience dissociation. In the test procedure for eye-roll sign measurement, the patient is told Hold your head looking straight forward; while holding your head in that position, look upward, toward your eyebrows, now toward the top of your head (up-gaze). While continuing to look upward, close your eyelids slowly (roll).
The up-gaze and roll are scored on a 0-to-4 scale by observing the amount of sclera visible between the lower eyelid and the lower edge of the cornea. This procedure takes approximately 5 seconds. The eye roll is a part of the hypnotic induction, which is also scored as an initial indicator of the potential for hypnotic experience. Also, in many patients, the eye roll alone can become a spontaneous rapid hypnotic induction in addition to providing initial information that is compared to the more traditional perceptual and motor items that follow.
The client is asked to :
1. Hold your head looking straight forward ;
2. While holding your head in that position, look upward toward your eyebrows— now toward the top of your head (UpGaze) ;
3. While continuing to look upward, at the same time close your eyelids slowly (Roll) ;
4. Now, open your eyes and let your eyes come back into focus.
The Up-Gaze and Roll are scored on a scale.
The amount of sclera visible between the lower eyelid and the lower edge of the cornea is the most practical measurement.