Evidence for the uniqueness of eidetic imagery

This research examined the performance of eidetic subjects, classified by the standard self-report criteria, on a set of objective and subjective measures. Eidetic subjects were statistically superior to controls on an 'accuracy of report' test and a superimposition task, but these differences were not so large as to provide compelling evidence for the uniqueness of eidetic imagery. Further experiments investigated the effects of stimulus manipulations--type of interference and level of illumination--on, respectively, visual retention and duration of phenomenal image. The pattern of effects differed markedly between eidetic subjects and a control group matched on a measure of capacity for visual memory. These findings provide converging evidence for a qualitative distinction between eidetic imagery and visual memory that does not rely on differences in storage capacity. Eidetic imagery appears to be a long-lasting, percept-like experience which varies considerably in clarity and definition; its duration is critically dependent on level of illumination and its contents are easily disrupted by after-coming visual stimuli.