ABSTRACT
It is customary in all branches of psychophysics to determine the limits of sensory systems from perceptual judgments. As an example, in the psychophysics of visual masking, responses in forced-choice tasks are conventionally considered as reports of the subjective experience arising from the masked stimulus. Such reports are supposed to summarize all information that is available to the visual system and to reflect the system’s limits of resolution for stimuli in close temporal vicinity. This assumption, however, is unwarranted to the degree that perception is possible without awareness, and dissociations between perceptual judgments and motor responses (e.g., grasping) presumably not based on awareness have in fact been demonstrated recently (Aglioti, DeSousa, & Goodale, 1995; but see Franz, Gegenfurtner, Bülthoff, & Fahle, 2000).
