Mental image

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A mental image is a term used in psychology, philosophy, and communication studies to describe the representation of an idea in a person's mind. According to some biologists and anthropologists[citation needed], the ability to form and recall mental images, to learn about the world from them, and to communicate to others about them is unique to the human species, while others claim to have found evidence of this capacity in other species. This debate in the biological sciences is generally ignored in modern and historical philosophy, which tends to focus on human cognition.

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[edit] How mental images form in the brain

Have you ever wondered why you seem to get a mental picture of something happening when you are reading a book? Or maybe when you have a daydream? These images that one experiences appear to be like pictures in your head. For example, when a musician hears a song they can sometimes "see" the song notes in their head. This is different from an after image. For example, after-image from an event that is induced is considered not under our conscious control. By contrast, however, when we call up an image in our imagination or minds, it is considered to be voluntary. Therefore, we can characterize our imagery as being various degrees of our conscious control.

According to some biologists[citation needed] our experiences of the world around us are stored as mental images which we can then associate and compare with other mental images and we can synthesize completely new images, for example when we dream or imagine. This theory states that this process allows us to form useful theories of how the world works based on likely sequences of mental images, without having to directly experience that outcome, for example through the processes of deduction or simulation. Whether other creatures have this capability is debated.

[edit] Philosophical ideas about mental images

Mental images are an important topic in classical and modern philosophy, as they are central to the study of knowledge. In the Republic book VII Plato uses the metaphor of a prisoner in a cave, bound and unable to move, sitting with his back to a fire and watching the shadows cast on the wall in front of him by people carrying objects behind his back. The objects that they are carrying are representations of real things in the world. The prisoner, explains Socrates, is like a human being making mental images from the sense data that he experiences.

More recently, Bishop Berkeley's proposed similar ideas in his theory of idealism. Berkeley stated that reality is equivalent to mental images — our mental images are not a copy of another material reality, but that reality itself. Berkeley, however, sharply distinguished between the images that he considered to constitute the external world, and the images of individual imagination. According to Berkeley, only the latter are considered "mental imagery" in the contemporary sense of the term.

The eighteenth century British writer, Dr. Samuel Johnson, criticized idealism. When asked what he thought about idealism (while out on a walk in Scotland) he is alleged to have replied "I refute it thus!" as he kicked a large rock and his leg rebounded. His point was that the idea that the rock was just another mental image and had no material existence of its own, was a poor explanation of the painful sense data he had just experienced.

David Deutsch addresses Johnson's objection to idealism in The Fabric of Reality[citation needed] when he states that if we judge the value of our mental images of the world by the quality and quantity of the sense data that they can explain, then the most valuable mental image — or theory — that we currently have is that the world has a real independent existence and that humans have successfully evolved by building up and adapting patterns of mental images to explain it. This is an important idea in scientific thought.

Critics of scientific realism ask[citation needed] how the inner perception of mental images actually occurs. This is sometimes called the "homunculus problem" (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 these philosophers, scientific realists cannot explain where the images and the perceiver of them exist in the brain or its functions. To use the analogy of the computer screen, these critics argue that cognitive science and psychology has been unsuccessful in identifying the component in the brain (e.g. 'hardware' such as a computer graphics card) or the mental processes that store these images (e.g. 'software' such as a graphics device driver).

[edit] Mental Imagery in Experimental Psychology

Cognitive psychologists and (later) cognitive neuroscientists have empirically tested some of the philosophical questions related to whether and how the human brain uses mental imagery in cognition.

One related theory of the mind that was examined in these experiments was the "brain as serial computer" philosophical metaphor of the 70s. Psychologist Zenon Plyshyn theorized that the human mind processes mental images by decomposing them into an underlying mathematical proposition. Roger Shepard and Jacqueline Metzler (1971) 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". 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" (Gardner 1987) 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.

This mental rotation finding implied that the human mind — and the human brain — maintains and manipulates mental images as topographic and topological wholes, an implication that was quickly put to test by psychologists. Kosslyn and colleagues (1995; see also 1994) showed in a series of neuroimaging experiments that the mental image of objects like the letter "F" are mapped, maintained and rotated as an image-like whole in areas of the human visual cortex. Moreover, Kosslyn's work showed that there were considerable similarities between the neural mappings for imagined stimuli and perceived stimuli. The authors of these studies concluded that while the neural processes they studied rely on mathematical and computational underpinnings, the brain also seems optimized to handle the sort of mathematics that constantly computes a series of topologically-based images rather than calculating a mathematical model of an object.

Recent studies in neurology and neuropsyhology on mental imagery have further questioned the "mind as serial computer" theory, arguing instead that human mental imagery is both visually and motorically embodied. For example, several studies 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 (Parsons 1987; 2003), and that patients with painful injured arms are slower at mentally rotating line drawings of the hand from the side of the injured arm (Schwoebel et al. 2001).

Some psychologists, including Stephen Kosslyn, have argued that such results occur because of interference in the brain between distinct systems in the brain that process the visual and motoric mental imagery. Subsequent neuroimaging studies (Kosslyn et al. 2001) showed that the interference between the motoric 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. However, Amorim et al. (2006) have recently showed 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. 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 (Rohrer 2006). 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.

[edit] Training and Learning Styles

Some educational theorists 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. Examples of these teaching methods include spoken components with a whiteboard or overheads.

Educational researchers have examined whether the experience of mental imagery effects 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 and 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." (Pascual-Leone et al 1995).

[edit] Psychiatric ideas about mental images

Mental images, and particular images from dreams, are the basis for the theories of Sigmund Freud about human behavior. His basic thesis was that our childhood experiences strongly influence the mental images that we make in later life. He believed that humans form mental images in the unconscious according to their "latent" desires and they are not aware of them in their conscious mind although, according to Freud, they have a major influence on human behavior.

[edit] See also

[edit] References

  • Deutsch, David. The Fabric of Reality. ISBN 0-14-014690-3. 
  • Amorim, Michel-Ange, Brice Isableu and Mohammed Jarraya (2006) Embodied Spatial Transformations: “Body Analogy” for the Mental Rotation. Journal of Experimental Psychology: General.
  • Garnder, Howard. (1987) The Mind's New Science: A History of the Cognitive Revolution New York: Basic Books.
  • Kosslyn, Stephen (1994) Image and Brain: The Resolution of the Imagery Debate. Cambridge, MA: MIT Press.
  • Kosslyn, Stephen M., William L. Thompson, Irene J. Kim and Nathaniel M. Alpert (1995) Topographic representations of mental images in primary visual cortex. Nature 378: 496-8.
  • Kosslyn, Stephen M., William L. Thompson, Mary J. Wraga and Nathaniel M. Alpert (2001) Imagining rotation by endogenous versus exogenous forces: Distinct neural mechanisms. NeuroReport 12, 2519-2525
  • McGabhann. R, Squires. B, 2003, 'Releasing The Beast Within — A path to Mental Toughness', Granite Publishing, Australia.
  • Parsons, Lawrence M. (1987) Imagined spatial transformations of one’s hands and feet. Cognitive Psychology 19: 178-241.
  • Parsons, Lawrence M. (2003) Superior parietal cortices and varieties of mental rotation. Trends in Cognitive Science 7: 515-551.
  • Pascual-Leone, Alvaro, Nguyet Dang, Leonardo G. Cohen, Joaquim P. Brasil-Neto, Angel Cammarota, and Mark Hallett (1995). Modulation of Muscle Responses Evoked by Transcranial Magnetic Stimulation During the Acquisition of New Fine Motor Skills. Journal of Neuroscience [1]
  • Pylyshyn, Zenon W. (1973). What the mind’s eye tells the mind’s brain: a critique of mental imagery. Psychological Bulletin 80: 1-24
  • Rohrer, T. (2006). The Body in Space: Dimensions of embodiment The Body in Space: Embodiment, Experientialism and Linguistic Conceptualization]. In Body, Language and Mind, vol. 2. Zlatev, Jordan; Ziemke, Tom; Frank, Roz; Dirven, René (eds.). Berlin: Mouton de Gruyter, forthcoming 2006.
  • Schwoebel, John, Robert Friedman, Nanci Duda and H. Branch Coslett (2001). Pain and the body schema evidence for peripheral effects on mental representations of movement. Brain 124: 2098-2104.
  • Shepard, Roger N. and Jacqueline Metzler (1971) Mental rotation of three-dimensional objects. Science 171: 701-703.

[edit] External links

  • Roadmind University The Roerich Psychodynamic Inventory (RPI) provides statisical data to determine the validity of mental imagery for cognition of the minds raw emotional state. (Dr. Robert Roerich MD.)
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