An ellipse discrimination with four distinct levels of difficulty was developed which provided a wide range of alternative responses rather than a binary choice. S‘s task was to judge in which of 6 clock orientations the minor axis of the ellipse was oriented. Although this procedure was evolved as propaedeutic to studying the effects of incidental, “subliminal,” unbeknown stimulation on such a discrimination, it should prove useful in other contexts whenever a difficult ellipse discrimination is required.
References
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BoardmanW. K.GoldstoneS.Effects of subliminal anchors upon judgments of size. Perceptual and Motor Skills, 1962, 14, 475–482.
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DavisP.Discrimination without awareness in a psychophysical task. Perceptual and Motor Skills, 1964, 18, 87–90.
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SilverM. J.Subliminal and incidental stimulation: A critical evaluation of research strategy and development of a new experimental method. Medfield, Mass.: Medfield Found., 1966. (Mimeo)
