backward masking

Quick Reference

A form of masking that occurs when perception of a stimulus called the test stimulus is reduced or eliminated by the presentation of a second stimulus called the masking stimulus which, in the case of visual masking, follows the test stimulus up to 500 milliseconds later—as when a row of printed letters is exposed for 50 milliseconds, long enough to make them easily legible in normal circumstances, and this is followed after 150 milliseconds by a dark ring surrounding the position of one of the letters, completely masking the letter and causing it to vanish from the array. When the test stimulus and masking stimulus do not overlap spatially, the phenomenon is called metacontrast. See also auditory masking, Libet's delay. Compare forward masking, simultaneous masking.

Subjects: Psychology.

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