ABSTRACT
Most theories of visual masking view the mask in relatively literal terms as a stimulus which destroys information to impair perception. Consequently, definitions of visual masking are phrased solely in terms of this perceptual impairment. In this chapter we consider the possibility that impairment results because the mask both creates misleading cues and destroys valid ones. A consequence of this view is that one need study more than just impairment, for example, one need explore the subject’s criterion content (Kahneman, 1968). Hake, Rodwan, and Weintraub’s (1966) noise reduction model, which emphasizes the misleading effects of irrelevant but compelling cues, formed the basis for a theory of metacontrast suppression. It was hypothesized that the reason the test appears dim is that information about its brightness is extracted by comparing its rapidly fading trace to a subsequently presented mask. Garner and Morton’s (1970) related views on perceptual independence were applied to a task involving recognition of a sequentially presented pair of letters, each of which could be a B or D, independently of the other. The obtained masking function was symmetric for forward and backward masking conditions.
