Visual masking

Visual masking is a reduction in the detectability of a brief (less than 100ms) visual stimulus (the test stimulus) by the presentation of a second stimulus (the masking stimulus).The term was introduced in 1925 by the French psychologist Henri Pieron. There are three types of masking depending on the order and time of presentation of the masking stimulus:


 * Forward masking. Here the masking stimulus is presented before the test stimulus.Where the two stimuli do not overlap spatially this is known as paracontrast
 * Simultaneous masking occurs when both stimuli are presented at the same time
 * Backward masking. Here the masking stimulus is presented after the test stimulus.Where the two stimuli do not overlap spatially this is known as metacontrast

Papers

 * Google Scholar
 * Humphreys, G. W. (1981) Direct vs indirect tests of the information available from masked displays: What visual masking does and does not prevent. British Journal of Psychology, 72, 323-330.