Forward and backward tactile recognition masking

Forward and backward tactile recognition masking were investigated with a 15 by 15 array of tactile point-stimulators with the use of targets consisting of line segments differing in location and orientation and a random-dot embedding mask. Ss were paid graduate student volunteers (three males and one female). Durations of targets and masks were varied, and interstimulus intervals ranged from zero to 300 msec. Increases in target duration over mask duration decreased forward, but not backward masking. Small increases in mask duration over target duration increased both forward and backward masking. Further large increases in mask duration increased backward masking, but had no effect on forward masking. The results were interpreted as indicating that forward masking is predominantly influenced by peripheral processes, while backward masking is the result of a combination of peripheral and central processes, in agreement with similar findings in audition and vision.