Subliminal perception and perceptual defense: Two sides of a single problem

Two perceptual phenomena are contrasted: subliminal perception and perceptual defense. The first refers to the registration of faint stimuli outside of awareness; the second refers to the nonrecognition of threatening stimuli. It is argued that both are part of a single continuum and should be studied together. A stimulus may register outside of awareness and bring about a change in perceptual sensitivity (perceptual defense); the same stimulus could then bring about a change in response (subliminal perception). Two conditions are found necessary for subliminal perception: 1) the stimulus must be relevant to subject, and 2) it must be maintained over time. The same conditions are presumably required for perceptual defense. An experiment is outlined which would test this formulation.