The concept of backward masking originated in

psychoacoustics Psychoacoustics is the branch of psychophysics involving the scientific study of sound perception and audiology—how humans perceive various sounds. More specifically, it is the branch of science studying the psychological responses associated wi ...

, referring to

temporal masking In audio signal processing, auditory masking occurs when the perception of one sound is affected by the presence of another sound.Gelfand, S.A. (2004) ''Hearing – An Introduction to Psychological and Physiological Acoustics'' 4th Ed. New York, ...

of quiet sounds that occur moments before a louder sound. In

cognitive psychology Cognitive psychology is the scientific study of mental processes such as attention, language use, memory, perception, problem solving, creativity, and reasoning. Cognitive psychology originated in the 1960s in a break from behaviorism, which ...

visual backward masking Visual processing abnormalities in schizophrenia are commonly found, and contribute to poor social function. There is evidence that schizophrenia affects perception of contrast and motion, control of eye movements, detection of visual contours, a ...

involves presenting one visual

stimulus A stimulus is something that causes a physiological response. It may refer to: *Stimulation **Stimulus (physiology), something external that influences an activity **Stimulus (psychology), a concept in behaviorism and perception *Stimulus (economi ...

(a "mask" or "masking stimulus") immediately after a brief (usually 30 ms) "target" visual stimulus resulting in a failure to consciously perceive the first stimulus.Breitmeyer, B.G. and Ogmen, H. (2007
''Visual masking''
Scholarpedia, 2(7):3330. It is widely used in

psychophysiological Psychophysiology (from Greek , ''psȳkhē'', "breath, life, soul"; , ''physis'', "nature, origin"; and , ''-logia'') is the branch of psychology that is concerned with the physiological bases of psychological processes. While psychophysiology ...

studies on

fear Fear is an intensely unpleasant emotion in response to perceiving or recognizing a danger or threat. Fear causes physiological changes that may produce behavioral reactions such as mounting an aggressive response or fleeing the threat. Fear ...

and

phobia A phobia is an anxiety disorder defined by a persistent and excessive fear of an object or situation. Phobias typically result in a rapid onset of fear and are usually present for more than six months. Those affected go to great lengths to avoi ...

s that investigate the preattentive nonconscious reactions to fear-relevant stimuli. It is unknown how a later stimulus is able to block an earlier one. However, one theory for this phenomenon, known as the ''dual channel interaction'' theory, proposes that a fast signal created by the second stimulus is able to catch up to and overcome a slower signal sent from the first impulse. A similar phenomenon can occur when a masking stimulus precedes a target stimulus rather than follows it: this is known as ''forward masking'', or visual forward masking when the stimulus is visual. While not consciously perceived, the masked stimulus can nevertheless still have an effect on

cognitive Cognition refers to "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought ...

processes such as

context Context may refer to: * Context (language use), the relevant constraints of the communicative situation that influence language use, language variation, and discourse summary Computing * Context (computing), the virtual environment required to s ...

interpretation. It has been shown that visually masked stimuli can elicit motor responses in simple reaction-time tasks (e.g. response priming) independent of their conscious visibility.Vorberg, D., Mattler, U., Heinecke, A., Schmidt, T., & Schwarzbach, J.: ''Different time courses for visual perception and action priming.'' In: ''Proceedings of the National Academy of Sciences USA'', Nr. 100, 2003, p. 6275-6280. It is a widespread belief that masked stimuli can be used for

psychological manipulation Manipulation in psychology is a behavior designed to exploit, control, or otherwise influence others to one’s advantage. Definitions for the term vary in which behavior is specifically included, influenced by both culture and whether referring t ...

(see

subliminal messages Subliminal stimuli (; the prefix ' literally means "below" or "less than") are any sensory stimuli below an individual's threshold for conscious perception, in contrast to stimuli (above threshold). A 2012 review of functional magnetic resonance ...

psychorama Psychorama, also called the precon process, is the act of communicating subliminal information through film by flashing images on the screen so quickly that they cannot be perceived by the conscious mind. It is a subset of subliminal messaging that ...

). However, the empirical evidence for subliminal persuasion is limited.

References

Audiology Hearing Acoustics Psychoacoustics {{psychology-stub