Mental image
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A mental image is a term used in 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 is 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
According to some biologists[citation needed] our experiences of the world around us is 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 process of deduction. 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 neurologists have empirically tested some of the philosophical questions related 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[citation needed] view of cognition "as a serial computer" 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. Shepard and Metzler stated that this mental rotation finding implied that the human mind--and the human human brain--maintains and manipulates mental images as topographic and topological wholes.
Some recent studies related to mental imagery provide further tests of these findings and others examine provide new ways to test whether the "mind as serial computer" theory is correct. One of these later 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).
Based on these findings, some psychologists, including Stephen Kosslyn, have suggested that this result occurred because of interference in the brain between systems in the brain that process the visual and motoric mental imagery. Kosslyn and colleagues (1995; see also 1994) showed in a series of neuroimaging experiments where 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 and concluded that they found evidence for this interference. Later neuroimaging studies (2001)[citation needed] confirmed 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. The authors of these studies concluded[citation needed] 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.
These and numerous related studies have led to a relative consensus within cognitive science and philosophy on the neural status of mental images[citation needed]. Psychological and neurological researchers generally agree[citation needed] that there is no homunculus inside the head viewing these mental images in the form of a brain structure or process dedicated to viewing these images and that we form mental images of objects with which we interact. The philosophical problem of how these images are stored and manipulated within the human brain, particularly within language and communication, remains an fertile area of study (Rohrer 2006)[citation needed].
[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 concious mind although, according to Freud, they have a major influence on human behavior.
[edit] See also
[edit] References
- 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.
- Deutsch, David. The Fabric of Reality. ISBN 0-14-014690-3.
- 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.
- Norman, Donald. The Design of Everyday Things. ISBN 0-465-06710-7.
- 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.
