Friday, 12 October 2012

Mental Imagery

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mental image is an experience that, on most occasions, significantly resembles the experience of perceiving some object, event, or scene, but occurs when the relevant object, event, or scene is not actually present to the senses.[1][2][3][4] There are sometimes episodes, particularly on falling asleep (hypnagogic imagery) and waking up (hypnopompic), when the mental imagery, being of a rapid, phantasmagoric and involuntary character, defies perception, presenting a kaleidoscopic field, in which no distinct object can be discerned.[5]
The nature of these experiences, what makes them possible, and their function (if any) have long been subjects of research and controversy in philosophypsychologycognitive science, and more recently, neuroscience. As contemporary researchers use the expression, mental images (or mental imagery) can occur in the form of any sense, so that we may experience auditory images,[6]olfactory images,[7] and so forth. However, the vast majority of philosophical and scientific investigations of the topic focus upon visualmental imagery. It has been assumed that, like humans, many types of animals are capable of experiencing mental images.[8] Due to the fundamentally subjective nature of the phenomenon, there is little to no evidence either for or against this view.
Philosophers such as George Berkeley and David Hume, and early experimental psychologists such as Wilhelm Wundt and William James, understood ideas in general to be mental images, and today it is very widely believed that much imagery functions as mental representations (or mental models), playing an important role in memory and thinking.[9][10][11][12] Some have gone so far as to suggest that images are best understood to be, by definition, a form of inner, mental or neural representation;[13][14] in the case of hypnagogic and hypnapompic imagery, it is not representational at all. Others reject the view that the image experience may be identical with (or directly caused by) any such representation in the mind or the brain,[15][16][17][18][19][20] but do not take account of the non-representational forms of imagery.
In 2010 IBM applied for a patent on how to extract mental images of human faces from the human brain. It uses a feedback loop based on brain measurements of the fusiform face area in the brain which activates proportionate with degree of facial recognition.[21]



[edit]How mental images form in the brain

Common examples of mental images include daydreaming and the mental visualization that occurs while reading a book. When a musician hears a song, he or she can sometimes "see" the song notes in their head, as well as hear them with all their tonal qualities.[22] This is considered different from an after-effect, such as an after-image. Calling up an image in our minds can be a voluntary act, so it can be characterized as being under various degrees of conscious control.
According to psychologist and cognitive scientist Steven Pinker,[23] our experiences of the world are represented in our minds as mental images. These mental images can then be associated and compared with others, and can be used to synthesize completely new images. In this view, mental images allow us to form useful theories of how the world works by formulating likely sequences of mental images in our heads without having to directly experience that outcome. Whether other creatures have this capability is debatable.

[edit]Philosophical ideas about mental images


Critics of scientific realism ask how the inner perception of mental images actually occurs. This is sometimes called the "homunculusproblem" (see also the mind's eye). The problem is similar to asking how the images you see on a computer screen exist in the memory of the computer. To scientific materialism, mental images and the perception of them must be brain-states. According to critics,[who?] scientific realists cannot explain where the images and their perceiver exist in the brain. To use the analogy of the computer screen, these critics argue that cognitive science and psychology has been unsuccessful in identifying either the component in the brain (i.e. "hardware") or the mental processes that store these images (i.e. "software").

[edit]Mental imagery in experimental psychology

MR TMR.jpg
One theory of the mind that was examined in these experiments was the "brain as serial computer" philosophical metaphor of the 1970s. Psychologist Zenon Pylyshyn theorized that the human mind processes mental images by decomposing them into an underlying mathematical proposition. Roger Shepard and Jacqueline Metzler challenged that view by presenting subjects with 2D line drawings of groups of 3D block "objects" and asking them to determine whether that "object" was the same as a second figure, some of which were rotations of the first "object".[24] Shepard and Metzler proposed that if we decomposed and then mentally re-imaged the objects into basic mathematical propositions, as the then-dominant view of cognition "as a serial digital computer"[25] assumed, then it would be expected that the time it took to determine whether the object was the same or not would be independent of how much the object was rotated. Shepard and Metzler found the opposite: a linear relationship between the degree of rotation in the mental imagery task and the time it took participants to reach their answer.
Recent studies in neurology and neuropsychology on mental imagery have further questioned the "mind as serial computer" theory, arguing instead that human mental imagery manifests both visually and kinesthetically. For example, several studies have provided evidence that people are slower at rotating line drawings of objects such as hands in directions incompatible with the joints of the human body,[27] and that patients with painful, injured arms are slower at mentally rotating line drawings of the hand from the side of the injured arm.[28]
Some psychologists, including Kosslyn, have argued that such results occur because of interference in the brain between distinct systems in the brain that process the visual and motor mental imagery. Subsequent neuroimaging studies[29] showed that the interference between the motor and visual imagery system could be induced by having participants physically handle actual 3D blocks glued together to form objects similar to those depicted in the line-drawings. Amorim et al. have recently shown that when a cylindrical "head" was added to Shepard and Metzler's line drawings of 3D block figures, participants were quicker and more accurate at solving mental rotation problems.[30] They argue that motoric embodiment is not just "interference" that inhibits visual mental imagery, but is capable of facilitating mental imagery.
These and numerous related studies have led to a relative consensus within cognitive science, psychology, neuroscience and philosophy on the neural status of mental images. Researchers generally agree that while there is no homunculus inside the head viewing these mental images, our brains do form and maintain mental images as image-like wholes.[31] The problem of exactly how these images are stored and manipulated within the human brain, particularly within language and communication, remains a fertile area of study.
One of the longest running research topics on the mental image has been the fact that people report large individual differences in the vividness of their images. Special questionnaires have been developed to assess such differences, including the Vividness of Visual Imagery Questionnaire (VVIQ) developed by David Marks. Laboratory studies have suggested that the subjectively reported variations in imagery vividness are associated with different neural states within the brain and also different cognitive competences such as the ability to accurately recall information presented in pictures[32] Rodway, Gillies and Schepman used a novel long-term change detection task to determine whether participants with low and high vividness scores on the VVIQ2 showed any performance differences.[33] Rodway et al. found that high vividness participants were significantly more accurate at detecting salient changes to pictures compared to low vividness participants.[34] This replicated an earlier study.[35]
Recent studies have found that individual differences in VVIQ scores can be used to predict changes in a person's brain while visualizing different activities.[36] Functional magnetic resonance imaging (fMRI) was used to study the association between early visual cortex activity relative to the whole brain while participants visualized themselves or another person bench pressing or stair climbing. Reported image vividness correlates significantly with the relative fMRI signal in the visual cortex. Thus individual differences in the vividness of visual imagery can be measured objectively.

[edit]Training and learning styles

Some educational theorists[who?] have drawn from the idea of mental imagery in their studies of learning styles. Proponents of these theories state that people often have learning processes which emphasize visual, auditory, and kinesthetic systems of experience.[citation needed] According to these theorists, teaching in multiple overlapping sensory systems benefits learning, and they encourage teachers to use content and media that integrates well with the visual, auditory, and kinesthetic systems whenever possible.
Educational researchers have examined whether the experience of mental imagery affects the degree of learning. For example, imagining playing a 5-finger piano exercise (mental practice) resulted in a significant improvement in performance over no mental practice — though not as significant as that produced by physical practice. The authors of the study stated that "mental practice alone seems to be sufficient to promote the modulation of neural circuits involved in the early stages of motor skill learning."[37]

[edit]Mental imagery, visualization and the Himalayan traditions

Vajrayana BuddhismBön and Tantra in general, utilize sophisticated visualization or imaginal (in the language of Jean Houston ofTranspersonal Psychology) processes in the thoughtform construction of the yidam sadhanakye-rim, and dzog-rim modes ofmeditation and in the yantrathangka, and mandala traditions, where holding the fully realized form in the mind is a prerequisite prior to creating an 'authentic' new art work that will provide a sacred support or foundation for deity.[38][39]

[edit]See also


  1. ^ McKellar, 1957
  2. ^ Richardson, 1969
  3. ^ Finke, 1989
  4. ^ Thomas, 2003
  5. ^ Wright, Edmond (1983). "Inspecting images". Philosophy 58 (223): 57-72 (see pp. 68-72).
  6. ^ Reisberg, 1992
  7. ^ Bensafi et al., 2003
  8. ^ AristotleOn the Soul III.3 428a
  9. ^ Pavio, 1986
  10. ^ Egan, 1992
  11. ^ Barsalou, 1999
  12. ^ Prinz, 2002
  13. ^ Block, 1983
  14. ^ Kosslyn, 1983
  15. ^ Sartre, 1940
  16. ^ Ryle, 1949
  17. ^ Skinner, 1974
  18. ^ Thomas, 1999
  19. ^ Bartolomeo, 2002
  20. ^ Bennett & Hacker, 2003
  21. ^ IBM Patent Application: Retrieving mental images of faces from the human brain
  22. ^ Sachs, Oliver (2007). Musicophilia: Tales of Music and the Brain. London: Picador. pp. 30–40.
  23. ^ Pinker, S. (1999). How the Mind Works. New York: Oxford University Press.
  24. ^ Shepard and Metzler 1971
  25. ^ Gardner 1987
  26. ^ Kosslyn 1995; see also 1994
  27. ^ Parsons 1987; 2003
  28. ^ Schwoebel et al. 2001
  29. ^ Kosslyn et al. 2001
  30. ^ Amorim et al. 2006
  31. ^ Rohrer 2006
  32. ^ Marks, 1973
  33. ^ Rodway, Gillies and Schepman 2006
  34. ^ Rodway et al. 2006
  35. ^ Gur and Hilgard 1975
  36. ^ Cui et al. 2007
  37. ^ Pascual-Leone et al. 1995
  38. ^ The Dalai Lama at MIT (2006)
  39. ^ Mental Imagery

[edit]Further reading

  • Barsalou, L.W. (1999). Perceptual Symbol Systems. Behavioral and Brain Sciences 22: 577-660.
  • Deutsch, David. The Fabric of RealityISBN 0-14-014690-3.
  • Fichter, C. & Jonas, K. (2008). Image Effects of Newspapers. How Brand Images Change Consumers’ Product Ratings. Zeitschrift für Psychologie / Journal of Psychology, 216, 226-234.
  • Marks, D.F. (1973). Visual imagery differences in the recall of pictures. British Journal of Psychology, 64, 17-24.
  • Marks, D.F. (1995). New directions for mental imagery research. Journal of Mental Imagery, 19, 153-167.
  • Norman, Donald. The Design of Everyday ThingsISBN 0-465-06710-7.
  • Plato. The Republic (New CUP translation into English)ISBN 0-521-48443-X.
  • Plato. Respublica (New CUP edition of Greek text)ISBN 0-19-924849-4.
  • Thomas, Nigel J.T. (1999). Are Theories of Imagery Theories of Imagination? An Active Perception Approach to Conscious Mental Content. Cognitive Science 23: 207-245.
  • Thomas, N.J.T. (2003). Mental Imagery, Philosophical Issues About. In L. Nadel (Ed.), Encyclopedia of Cognitive Science(Volume 2, pp. 1147–1153). London: Nature Publishing/Macmillan.

[edit]External links

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