- Dual-coding theory
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Dual-coding theory, a theory of cognition, was first advanced by Allan Paivio of the University of Western Ontario. The theory postulates that both visual and verbal information are processed differently and along distinct channels with the human mind creating separate representations for information processed in each channel. Both visual and verbal codes for representing information are used to organize incoming information into knowledge that can be acted upon, stored, and retrieved for subsequent use.
Each channel also has limitations. For example, humans have difficulty simultaneously attending to multiple auditory or visual cues, depending on expertise with the task or prior knowledge with the subject area. For example, a television documentary that shows images of plant and animal life in a rain forest while also simultaneously providing narration that describes the animal life could potentially provide for improved learning using the dual-code theory because the visual and verbal information does not compete with each other.
A multimedia presentation that shows multiple visuals such as an image of a speaker as well as the text that the speaker is reading, such as a series of bullet points, could overwhelm the viewer, depending on the person and the situation, because the viewer must now attend to two images.
Contents
Analogue Codes
According to Paivio, mental images are analogue codes, while the verbal representation of words are symbolic codes. Analogue codes represent the physical stimuli we observe in our environment, such as trees and rivers. These codes are a form of knowledge representation that retains the main perceptual features of what is being observed. Symbolic codes, on the other hand, are a form of knowledge representation chosen to represent something arbitrarily, as opposed to perceptually. Similar to the way a watch may represent information in the form of numbers to display the time, symbolic codes represent information in our mind in the form of arbitrary symbols, like words and combinations of words, to represent several ideas. Each symbol (x, y, 1, 2, etc.) can arbitrarily represent something other than itself. For instance, the letter x is often used to represent more than just the concept of an x, the 24th letter of the alphabet. It can be used to represent a variable x in mathematics, or a multiplication symbol in an equation. Concepts like multiplication can be represented symbolically by an "x" because we arbitrarily assign it a deeper concept. Only when we use it to represent this deeper concept does the letter "x" carry this type of meaning.
Support for this theory
Supporting evidence comes from research that shows that memory for some verbal information is enhanced if a relevant visual is also presented or if the learner can imagine a visual image to go with the verbal information. Likewise visual information can often be enhanced when paired with relevant verbal information, whether real-world or imagined (Anderson and Bower, 1973).
Research with PET scans and fMRI, for example, has shown that participants used the same brain areas to process imagined visuals as images that were actually seen. Participants also had improved memory for spoken words and sentences when paired with an image, imagined or real, and showed increased brain activation to process abstract words not easily paired with an image.
Paivio found that participants when shown a rapid sequence of pictures as well as a rapid sequence of words and later asked to recall the words and pictures, either in order of appearance, or in any order they wanted, were better at recalling images when allowed to do so in any order. Participants, however, more readily recalled the sequential order of the words, rather than the sequence of pictures. These results supported Paivio's hypothesis that verbal information is processed differently than imaginal, or visual, information and that verbal information was superior to visual information when sequential order was also required for the memory task (Paivio, 1969).
Working memory as proposed by Alan Baddeley includes a two-part processing system with a visuospatial sketchpad and a phonological loop which essentially maps to Paivio’s theory.
Dual-coding theories complement a dual-route theory of reading. When people read written information, dual-route theory contends that the readers access orthographic and phonological information to recognize words in the writing.
Paivio’s work has implications for literacy, visual mnemonics, idea generation, HPT, human factors, interface design, as well as the development of educational materials among others. It also has implications for, and counterparts in, cognitive sciences and computational cognitive modeling (in the form of dual process cognitive models and so on; e.g., Anderson, 2005; Just et al., 2004, Sun, 2002). It also has had implications for cognitive robotics.
For further reading
References
- Anderson, J. R. (2005). Cognitive Psychology and its implications. New York: Worth Publishers.
- Anderson, J. R. & Bower, G. H. (1973). Human associative memory. Washington, DC: Winston.
- Baddeley, A. D. (1986). Working memory. Oxford: Oxford University Press.
- Denis, M. and Mellet, E. (2002). Neural bases of image and language interactions. International Journal of Psychology, 37 (4), 204-208.
- Just, M. et al. (2004). Imagery in sentence comprehension: an fMRI study. NeuroImage 21, 112-124.
- Mayer, R. E. & Moreno, R. (2003). Nine ways to reduce cognitive load in multimedia learning. Educational Psychologist, 38(1), 43-52.
- Moreno, R., & Mayer, R. E. (2000). A coherence effect in multimedia learning: the case for minimizing irrelevant sounds in the design of multimedia instructional messages. Journal of Educational Psychology, 92, 117-125.
- Paivio, A (1969). Mental Imagery in associative learning and memory. Psychological Review, 76(3), 241-263.
- Paivio, A (1971). Imagery and verbal processes. New York: Holt, Rinehart, and Winston.
- Paivio, A (1986). Mental representations: a dual coding approach. Oxford. England: Oxford University Press.
- Sternberg, Robert J. (2006). Cognitive psychology fourth edition. Thomson Wadsworth. pp. 234–36. ISBN 0534514219.
- Sun, R. (2002). Duality of the Mind. Mahwah, NJ: Lawrence Erlbaum Associates.
External links
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