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A mental image or mental picture is the representation in a person's mind of the physical world outside of that person.〔Eysenck, M. W. (2012). Fundamentals of cognition, 2nd ed. New York, NY: Psychology Press.〕 It 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.〔McKellar, 1957〕〔Richardson, 1969〕〔Finke, 1989〕〔Thomas, 2003〕 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. The nature of these experiences, what makes them possible, and their function (if any) have long been subjects of research and controversy in philosophy, psychology, cognitive science, and, more recently, neuroscience. As contemporary researchers use the expression, mental images or imagery can comprise information from any source of sensory input; one may experience auditory images,〔Reisberg, 1992〕 olfactory images,〔Bensafi et al., 2003〕 and so forth. However, the majority of philosophical and scientific investigations of the topic focus upon ''visual'' mental imagery. It has sometimes been assumed that, like humans, some types of animals are capable of experiencing mental images.〔Aristotle: ''On the Soul'' III.3 428a〕 Due to the fundamentally introspective 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. Today it is very widely believed that much imagery functions as mental representations (or mental models,) playing an important role in memory and thinking.〔Pavio, 1986〕〔Egan, 1992〕〔Barsalou, 1999〕〔Prinz, 2002〕 William Brant (2013, p. 12) traces the scientific use of the phrase "mental images" back to the John Tyndall's 1870 speech called the "Scientific Use of the Imagination." 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;〔Block, 1983〕〔Kosslyn, 1983〕 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,〔Sartre, 1940〕〔Ryle, 1949〕〔Skinner, 1974〕〔Thomas, 1999〕〔Bartolomeo, 2002〕〔Bennett & Hacker, 2003〕 but do not take account of the non-representational forms of imagery. In 2010, IBM applied for a patent on a method 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 that activates proportionate with degree of facial recognition.〔(IBM Patent Application: Retrieving mental images of faces from the human brain )〕 It was issued in 2015.〔(Business Machines : Patent Issued for Retrieving Mental Images of Faces from the Human Brain )〕 ==How mental images form in the brain== Common examples of mental images include daydreaming and the mental visualization that occurs while reading a book. Another is of the pictures summoned by athletes during training or before a competition, outlining each step they will take to accomplish their goal.〔Plessinger, Annie. ''The Effects of Mental Imagery on Athletic Performance''. The Mental Edge. 12/20/13. Web. http://www.vanderbilt.edu〕 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. 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,〔Pinker, S. (1999). ''How the Mind Works''. New York: Oxford University Press.〕 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. There are several theories as to how mental images are formed in the mind. These include the Dual-Code Theory, the Propositional Theory, and the Functional-Equivalency Hypothesis. The Dual-Code Theory, created by Allan Paivio in 1971, is the theory that we use two separate codes to represent information in our brains: image codes and verbal codes. Image codes are things like thinking of a picture of a dog when you are thinking of a dog, whereas a verbal code would be to think of the word "dog".〔Paivio, Allan. 1941. ''Dual Coding Theory. Theories of Learning in Educational Psychology''. (2013). Web. http://www.lifecircles-inc.com/Learningtheories/IP/paivio.html〕 Another example is the difference between thinking of abstract words such as ''justice'' or ''love'' and thinking of concrete words like ''elephant'' or ''chair.'' When abstract words are thought of, it is easier to think of them in terms of verbal codes- finding words that define them or describe them. With concrete words, it is often easier to use image codes and bring up a picture of a ''human'' or ''chair'' in your mind rather than words associated or descriptive of them. The Propositional Theory involves storing images in the form of a generic propositional code that stores the meaning of the concept not the image itself. The propositional codes can either be descriptive of the image or symbolic. They are then transferred back into verbal and visual code to form the mental image.〔Mental Imaging Theories. 2013. Web. http://faculty.mercer.edu〕 The Functional-Equivalency Hypothesis is that mental images are "internal representations" that work in the same way as the actual perception of physical objects.〔Eysenck, M. W. (2012). ''Fundamentals of Cognition'', 2nd ed. New York, NY: Psychology Press.〕 In other words, the picture of a dog brought to mind when the word ''dog'' is read is interpreted in the same way as if the person looking at an actual dog before them. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「mental image」の詳細全文を読む スポンサード リンク
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