Splitting Visual Illusions into Groups - Essay Example

?Running Header: Splitting visual illusions into groups Introduction An illusion refers to a distortion of senses; hence, revealing the way in which the brain arranges and interprets sensory stimulation. Visual or optical illusions entail the application of colors, shapes and line distortions so as to trick the brain and the eye. When looking at confusing images, human brain can at times interpret visual data wrongly, or it can just fill in the missing pieces of information. As a result, human beings end up obtaining misleading or deceptive images in their brains. Therefore, this paper sheds light on a possible way in which a wide range of optical illusions are categorized and why they optical illusions occur. Categorizing optical illusions Due to the fact that visual illusions are numerous, it is vital that they are grouped in certain ways in order to ease their understanding. Kanizsa (1976, pp. 48-52) notes that different factors are responsible for the grouping of optical illusions, and these include angles, light, distance, depth, color and influence of the visual field’s location. Grouping of visual illusions is done by the human mind in order to simplify their complexities. In fact, the mind does this in form of piles in order to attend to fewer things that it would for individual objects. In Gestalt psychology, grouping is done on the visual illusions in order to minimize the number of objects to be kept in human memory (Zanker, 2010, pp. 150-165). 1. Cognitive illusions Many individuals believe that these illusions result from the interaction with human assumptions on the world; hence causing the creation of unconscious inferences. This idea was proposed by Hermann Helmholtz during the 19th century (Gregory, 1968, pp. 66-76). In turn, cognitive illusions are categorized into distorting illusions, ambiguous illusions, fiction illusions, or paradox illusions. Ambiguous illusions To start with, Gregory (1968, pp. 176-196) maintains that ambiguous illusions refer to objects or pictures that bring out a perceptual switch between different interpretations. This implies that the visual system interprets objects or pictures in the many ways. In the human eye, the shape or image in the retina is constant since one cannot see a mixture of two perceptions. Here, an individual can perceive one of the images at a go, though they can visually flip forth and back. This is type of illusions is best demonstrated by the Rubin vase and the Necker cube. Distorting illusions According to Zanker (2010, pp. 150-165), these illusions have length, size, or curvature, and they make objects appear shorter, longer, bigger, smaller, or have a different shape. Some of these illusions include cafe wall illusion and Mueller-Lyer illusion. The cafe wall was initially described by Richard Gregory, who observed that the curious impact of the tiles of a cafe bottom at St. Michael’s Hill in Bristol. According to him, the straight and parallel horizontal lines seemed to be bent by the optical illusion (Goldstein, 2010, pp. 177-180). In the other example, optical illusion consists of nothing but an arrow. Here, viewers place a mark at the middle, and they place it almost at the tail end. Fiction illusion Gregory (1968, pp. 176-196) asserts that these are illusions that entail the perceptions of objects, which are sincerely not there, but one observer, such as, those ones caused by hallucinogenic drugs or schizophrenia. Paradox visual illusions These ones give objects are impossible or paradoxical when perceived by individuals. Some of the examples include impossible staircases or Penrose triangle in M.C.Escher’s work (Gregory, 1968, pp. 176-196). Here, the triangle is an illusion that depends on cognitive misunderstanding that bordering edges should join. These illusions arise from perceptual learning. 2. Physiological illusions According to Goldstein (2010, pp. 177-180), these are illusions that occur as afterimages of bright lights or effects of the brain or eyes of too much stimulation or interaction with competing or contextual stimuli of a particular type, such as, color, brightness, position, size, tile and movement. Here, Kanizsa (1976, pp. 48-52) argues that the theoretical explanation is that the stimulus gets to follow its individual neutral path in the initial stages of optical processing, and that repetitive or intense activity in that, or contact with active adjacent channels lead to a physiological imbalance, which alters perception . The best illustrations of these illusions are in Hermann’s Mach bands and grid illusions, which are demonstrated by use of a biological method. 3. Text visual illusions Gregory (1968, pp. 66-76) notes that these refer to the perceptions of objects that are formed from strategic positioning of numbers and letters. Shifting of numbers and letters in a can offers an object animation. Causes of visual illusions One of the causes of the optical illusions is the intricate, but interesting design of the visual mechanism in human eyes. This is because human eye is constructed in such a way that two nerves cells (rod and cones) are separately placed around and on human retina (Goldstein, 2010, pp. 177-180). While the cone cells senses color, the rod cells senses the low-light contrasts. Together, the two nerve cells work together to change light into the neural signals. The optic nerves are responsible for the transmission of the signals to the brain. Because the retina’s edges have fewer cones than rods, and the retina center has cones, seeing form the corner of one’s eyes is indeed deceptive. In order to see clear images, individuals should be turned since the sharpest mages form in the central part of the retina. Another cause of optical illusion is too much exposure to the alternate brightness, patterns, color or tilt, and this affects the kind of perceptions by human eyes (Ratliff, 1972, pp.90-101). Consistent stimulation of particular brain regions can give rise to psychological imbalance; hence affecting resultant optical perceptions. Repeated exposure of some color with certain level of brightness wears human eyes out, due to which they might perceive objects differently. Therefore, too much exposure to some visual gives rise to optical illusions (White, 1979, pp. 413-416). Some illusions are known to be caused by medical disorders like schizophrenia. This mostly happens to individuals that suffer from neuropsychological ailments face illusions in many things around them. This is because of brain disorder that causes them to mistake objects, that is, perceiving them differently from the reality. Optical illusions are also caused by differences in color shades since they create depth for flat surfaces. Conclusion An illusion entails a distortion of senses, which reveals the way in which the brain arranges and interprets sensory stimulation. Some of the categories of visual illusions include cognitive, paradoxical, ambiguous, distorting, fiction, text and physiological illusions. Optical illusions occur due to too much exposure on certain visuals, neuropsychological disorders, and the visual human eye design mechanism. References Goldstein, E. (2010). Sensation and perception (7th ed.). Belmont, Calif, CA: Wadsworth Cengage Learning. pp. 177-180 Gregory, R.L. (1968). Perceptual illusions and brain models. Royal Society B 171(4), 179-196. Gregory, R.L. (1968). Visual illusions. Scientific American, 219(4), 66-76. Kanizsa G. (1976). Subjective Contours. Scientific American 234(5), 48-52. Ratliff, F., (1972). Contour and Contrast. Scientific American, 226 (2), 90-101. White, M. (1979). A new effect of pattern on perceived lightness. Perception 8(3), 413-416. Zanker, J. (2010). Sensation, perception and action: an evolutionary perspective. Basingstoke: Palgrave Macmillan. pp. 150-165. Read More