unconscious information processing in humans.

Maria Kyriacou

Jeremy does not believe that there is such a thing as unconscious information processing in humans. ‘And even if there was’, he says, ‘there is no way we could know about it, because it is unconscious’. You are about to apply, when he adds, ‘And I don’t see the point in anything being unconscious anyway, because it does’t have any affect on us and it is of no use to anybody’.

Introduction

The terms conscious and unconscious are used in everyday conversation but their scientific meaning is often unclear. In lay terms most people are aware of being aware (conscious) but have experienced occasions whereby they are still somehow aware of something without realising they are aware (unconscious). Many believe that consciousness and an ability to communicate go hand in hand (Carlson 2001a). Therefore without consciousness there would be no communication, so there would be little point for humans, as Jeremy indicates. However there are situations where there is awareness that can be communicated, but there is a complete absence of consciousness of this awareness. These include subliminal messages and the phenomenon of blindsight, both of which are discussed below, following a brief review of the psychological understanding of consciousness.

The psychological understanding of consciousness

The renowned psychologist Sigmund Freud believed that speech errors (‘Freudian slips’) provide a window into the unconscious processing occurring in an individuals brain (Parkin 1996b). Thus, if an individual makes a mistake in their normal language, this indicates that there is an unconscious element to what they are thinking about or saying, of which they are unaware. Despite this lack of awareness the unconscious processing impacts the consciousness to such as extent that it would manifest in the individual’s speech. Freud believed that this unconscious processing was ordinarily repressed (Kelly, Alvarado 2005Frederick Myers believed that the theory of consciousness should be derived from a unified model of the mind (Kelly, Alvarado 2005). As such, any phenomenon with a subliminal origin, such as dreams, multiple personality and telepathy; Myers ‘automatisms’; are merely manifestations of what is always going on in the mind but are normally separated from conscious processing by some form of barrier. Thus the subliminal self forms the largest part of the self and it’s processing (Kelly, Alvarado 2005). In contrast to Freud’s theory of repression Myers believed that unconscious automatisms are completely normal and it just takes special situations for them to become conscious.

Subliminal processing

In tests of subliminal processing happy, angry or neutral faces would be presented to a study participant for 16 milliseconds, prior to a visible neutral face. Following this the participant was required to consume a drink, which they were to assess in terms of a price that they would be prepared to pay for it (Toates 2006). Participants were unaware of the initial face as the presentation time was too short for conscious processing, but it was processed at an unconscious level. Results indicated that a happy face was associated both with a higher consumption level and a ...

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Subliminal processing

In a further test of subliminal processing backward masking was used by Anthony Marcel in a semantic similarity test. In this an initial, rapidly presented, stimulus of either a blank card or a real word would come before an image of jumbled broken letter shapes (Datta 2006). Participants were told that a word had been presented (even though they were not consciously aware of this) and were asked to choose between two words for the one most semantically similar. Results showed that, as the time between the (consciously invisible) word and its masking stimulus (jumbled shape) was reduced, a greater proportion of correct answers were given. This was despite participants categorically saying that they had seen no stimulus word. However, the evidence was that they had seen the word unconsciously, but not consciously.

Blindsight

Blindsight is a phenomenon in which an individual is unable to see an object in their blind field but is able to accurately reach for the object (Carlson 2001a). The damage associated with blindsight involves the contralateral part of the visual field (Datta 2006), eg the part of the primary visual striate cortex that is involved in the processing of vision in the human (Parkin 1996a).

Patient DB had an area of damage in his brain corresponding with the upper radiations of the right visual cortex, and was unable to see items presented in the lower left quadrant of each eye (Parkin 1996a). He specifically said that he was unable to consciously see items but recognised that he was able to locate them, which indicated unconscious processing (Datta 2006). This unconscious processing is believed to occur in the extrastriate cortex, eg the subcortical visual system (Farah, O'Reilly & Vecera 1993), which includes the superior colliculus and dorsal lateral geniculate nucleus (Carlson 2001b).

Blindsight has also been replicated in other mammals. A monkey called Helen had her complete primary visual cortex destroyed so that she was unable to see anything consciously (Datta 2006). This differed from DB in that he was still able to see items in most of his visual field, just not the lower left quadrant (Parkin 1996a). Helen was, however, able to reach out and pick up items such as currants placed in front of her and could navigate a maze of obstacles placed in her path (Datta 2006). Thus visual information was able to control behaviour and consequent movement without a need for any conscious perception or processing of this visual sensation (Carlson 2001a).

Conclusion

Whilst conscious processing is the aspect of our brain that we are most aware of, there is undeniable unconscious processing occurring as well. Whilst the exact form of this is subject to debate amongst psychologists following Freud and Myers, evidence from experiments categorically prove its existence. Both subliminal images and blindsight prove that the human brain is able to process information presented to it, without any need for conscious processing to be present. The reasons for this could be many and include safety, rapid responses, and automation in terms of reducing processing requirements of the brain. Whatever the purpose unconscious processing does occur and is of significant value to humans and other mammals.

References

Carlson, N. 2001a, "Introduction" in Physiology of Behaviour, 7th edn, Allyn and Bacon, Boston, pp. 1-25.

Carlson, N. 2001b, "Vision" in Physiology of Behaviour, 7th edn, Allyn and Bacon, Boston, pp. 160-200.

Datta, S. 2006, "Understanding the mind" in From cells to consciousness, eds. S. Datta, I. Lyon & B. MacKintosh, et al, 2nd edn, The Open University, Milton Keynes, pp. 139-180.

Farah, M.J., O'Reilly, R.C. & Vecera, S.P. 1993, "Dissociated overt and covert recognition as an emergent property of a lesioned neural network", Psychological review, vol. 100, no. 4, pp. 571-588.

Kelly, E.W. & Alvarado, C.S. 2005, "Frederic William Henry Myers, 1843-1901", American Journal of Psychiatry, vol. 162, no. 1, pp. 34.

Parkin, A.J. 1996a, "Blindsight" in Explorations in Cognitive neuropsychology, ed. A.J. Parkin, 1st edn, Psychology Press, Hove, East Sussex, pp. 24-37.

Parkin, A.J. 1996b, "Spoken language impairments" in Explorations in Cognitive neuropsychology, ed. A.J. Parkin, 1st edn, Psychology Press, Hove, East Sussex, pp. 129-153.

Toates, F. 2006, "Introduction to brains, mind and consciousness" in From cells to consciousness, eds. S. Datta, I. Lyon & B. MacKintosh, et al, 2nd edn, The Open University, Milton Keynes, pp. 1-42

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