A signal detection study of the effects of suggested improvement on the monocular visual acuity of myopes

See Clearly: Suggestion, Hypnosis, Attention, and Visual Acuity

“…These claims remained neither contested nor confirmed for a whole decade until Sheehan et al (1982), employing a better-controlled experimental design, reported similar findings using a signal detection task. 4 Presenting d 0 scores (i.e., measuring how accurately an observer identifies a stimulus) and controlling for potential sampling differences 4 In signal detection theory, the detection of a stimulus depends both on the observer's sensitivity and on higher decisional and motivational factors.…”

“…Methodologically, there also are a number of caveats to keep in mind. As Sheehan et al (1982) pointed out, in their first experiment, Graham and Leibowitz (1972) did not match their control groups: control subjects were not suggestibility-matched with the highly suggestible experimental group and were thus almost certainly of lower suggestibility. This alone can explain the results of Experiment 1 (i.e., the effect measured may have resulted not from the presence or absence of suggestions but from the inequality of the groups compared).…”

“…Plagued by a checkered history, hypnosis suffers from a reputation stained by myths and folklore belying its promise in mainstream research. Nonetheless, the scientific literature contains multiple abstracts (e.g., Harwood, 1970;Harwood & Ward, 1972;Leibowitz, Graham, & Stein, 1972) and reports describing the effects of positive suggestion on the improvement of visual acuity (e.g., Graham, 1971;Sheehan, Smith, & Forrest, 1982). A scrutiny of these reports reveals that a report by Graham and Leibowitz was probably the cornerstone of these data, especially considering the important work Herschel Leibowitz carried out in visual science (e.g., Leibowitz, Brislin, Perlmutt, & Hennessy, 1969).…”

Study of the Therapeutic Effects of Proximal Intercessory Prayer (STEPP) on Auditory and Visual Impairments in Rural Mozambique

“…Could observed effects be attributable to suggestion or hypnosis (12)? Sheehan et al (1982) showed that a few minutes of suggestion led to statistically significant visual acuity improvement, but the effect was so small that a subject would not be able to read one line smaller on the Snellen chart (13). Several studies of hypnotic suggestion showed an average 2 (14) or 2.5 (15) times increase in visual acuity, with the largest reported improvement from 6/60 to 6/6 (13), despite no measurable changes in ocular refraction.…”

“…Indeed, researchers have investigated effects of suggestion and hypnosis on vision and hearing and claimed significant effects (13)(14)(15). We pursued two research and Pemba city) Iris leaders invited the "deaf" and "blind" to designated areas to receive prayer for healing by themselves and other Western and Mozambican affiliates.…”