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Perceptual set theory – stresses the idea of perception as an active process involving selection, inference and interpretation.

Perceptual set is a bias or readiness to perceive aspects of available sensory data and to ignore others. Thus, perceiving and recognizing depend not only on objective qualities / features of the object, but also on the condition the organism is in, called perceptual set (perceptual readiness). Perceptual set is the easiness with which a given category is used for perceiving a given material. It depends on two groups of factors: external and internal. External factors are responsible for learning the probability / likelihood of occurrence of a certain object in a given category. If one expects a given object to occur, he or she will recognize it more easily. A typical example of the influence of external factors is the phenomenon of priming: if man has been previously, consciously or subliminally, informed about the kind of stimuli to be exposed, their recognition will be easier. Internal factors are connected with the internal organization of categories one uses when perceiving.

External factors affecting perceptual set include:

  • Frequency – how often objects of a given category occurred in the past; o Social consequences – categories used by others seem more “ready”, e.g. in ambiguous situations, this can be confirmed by such social phenomena as

stereotyping, conformity, or diffusion of responsibility,

  • Context – e.g. ABC / 12,13,14 (Minturn and Bruner, 1951), o past experience – e.g. playing cards with black hearts and red spades on a tachistoscope would be seen as normal cards t first (Bruner and Postman, 1949).

Internal factors affecting perceptual set include:

  • Monopoly – the number of categories used by an individual; the fewer categories, the stronger the monopoly; this is very evident with black-or-while perception, and with dogmatic people. The perceptual readiness of dogmatic people is extremely high, which might lead to psychopathology. Paranoia can be defined as having a highly integrated system of illusions of very high perceptual readiness. o The integrity of the system of categories – the more connected are the categories with one another, the more perceptually ready they are. E.g. “apple” category is more ready, because it is” fruit / edible / plant / organic substance/ etc., while e.g. “alien” is only a being from another planet, and therefore is less ready. Therefore, coming across an apple-like alien, we are more likely to categorize him/her (?) as an apple…
  • Motivation – categories connected with the aims an individual has are more ready than indifferent categories. E.g. pictures of food and drink were perceived as brighter than other pictures by subjects who had been deprived of food and liquid (Gilchrist and Nesberg, 1952).
  • Emotion – taboo words on a tachistoscope – slower recognition (McGinnes, 1949) threatening signals cause the decrease of perceptual readiness (:perceptual defence) –at the same time, those taboo words arouse emotionally – which might mean that emotional recognition and cognitive recognition are two separate processes.

(+) set theory links with schemata theory and stereotypes;

(+) ample empirical support