Perception Outline Chapter 6, Psychology, David G Meyers, 7 th Edition

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1 Perception Outline Chapter 6, Psychology, David G Meyers, 7 th Edition By transforming sensation into perception we create meaning - Selective Attention - Perception comes to us moment by moment 1. Selective Attention the focusing of conscious awareness on a particular stimulus, as in the cocktail party effect Cocktail Party Effect the ability to attend to only one voice among many Consciously, whatever has your attention pretty much has your undivided attention Change blindness is very common when we are focused on one aspect of a scene We can react to a stimuli that we were not focused on o [music played in one ear while direction attention to the other ear was later rated higher or preferred over random music] 2. Visual Capture the tendency for vision to dominate the other senses. - Perceptual Organization - 3. Gestalt an organized whole. Gestalt psychologists emphasize our tendency to integrate pieces of information into meaningful wholes o Whole may exceed the sum of its parts Sensation not just bottom-up and perception not just top-down o Sensation and Perception are one continuous process We constantly filter sensory information and infer perceptions in ways that make sense to us Form Perception 4. Figure-Ground the organization of the visual field into objects [figures] that stand out from their surroundings [ground] o The first perceptual Task Next we have to organize the figure into a meaningful form We process color, movement, and light/dark contrast automatically 5. Grouping the perceptual tendency to organize stimuli into coherent groups o Idea that the perceived whole differs from the sum of its parts Proximity we group nearby figures together. We see not six separate lines, but three sets of two lines Similarity figures similar to each other we group together. We see triangles and circles as vertical columns of similar shapes, not as horizontal rows of dissimilar shapes

2 Continuity We perceive smooth, continuous patterns rather than discontinuous ones. This pattern could be a series of alternating semicircles, but we perceive it as two continuous lines; one wavy, one straight Connectedness when they are uniformed and linked, we perceive spots, lines, or areas as a single unit. Closure we fill in gaps to create a complete, whole object. Depth Perception 6. Depth Perception the ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance The ability is partly innate 7. Visual Cliff a laboratory device for testing depth perception in infants and young animals Used in experiments by Gibson and Walk 8. Binocular Cues Depth cues, such as retinal disparity and convergence that depend on the use of two eyes. Our eyes are 2 ½ inches apart, producing slightly different images. 9. Retinal Disparity a binocular cue for perceiving depth: by comparing images from two eyeballs, the brain computes distance the greater the disparity (difference) between the two images, the closer the object. Two viewpoints (cameras) are used to create 3D movies, as our eyes would Sensations are disassembled into information bits that the brain reassembles into its own functional model of the external world. 10. Convergence a binocular cue for perceiving depth; the extent to which the eyes converge inward when looking at an object o Neuromuscular cue: brain measures the eyes angle of convergence 11. Monocular Cues distance cues, such as linear perspective and overlap, available to either eye alone. Good for far away objects where retinal disparity is minimal Relative Size if we assume that two objects are similar in size, we perceive the one that casts the smaller retinal image as farther away Interposition If one object partially blocks our view of another, we perceive it as closer Relative Clarity Because light from distant objects passes through more atmosphere, we perceive hazy objects as farther away than sharp, clear objects. Texture Gradient a gradual change from a coarse, distinct texture to a fine, indistinct texture signals increasing distance. Relative Height we perceive objects higher in our field of vision as farther away. This contributes to the illusion that vertical dimensions are longer than horizontal. Relative Motion (Motion Parallax) As we move objects that are actually stable may appear to move.

3 o The nearer the object, the faster it appears to move o Objects closer to you than your fixation point appear to move backward o Your brain uses these speed and direction clues to compute the relative distance Linear Perspective Parallel lines (railroad tracks) appear to converge with distance. The more the lines converge, the greater the perceived distance. Light and Shadow nearby objects reflect more light into our eyes. Dimmer objects seem farther away. Brain assumes light comes from above. - Motion Perception - Brain assumes shrinking objects are retreating, enlarging objects are approaching Large objects appear to move more slowly than smaller objects Stroboscopic Movement interpretation of a series of slightly varying images as continuous movement 12. Phi Phenomenon an illusion of movement created when two or more adjacent lights blink on and off in succession - Perceptual Constancy Perceptual Constancy perceiving objects as unchanging (having consistent lightness, color, shape, and size) even as illumination and retinal images change. o Identify regardless of angle, distance, or illumination Shape Constancy allows us to perceive familiar objects shapes as constant even though our retinal image changes Lightness Constancy we perceive an object as having constant lightness even while its illumination varies. Changes with context. - Perceptual Interpretation- Immanuel Kant said knowledge came from our inborn ways or organizing sensory experiences John Locke said that through our experiences we learn to perceive the world There is a critical period for perceptual development We retain the imprint of early visual experiences into the future 14. Perceptual Adaption in vision, the ability to adjust to an artificially displaced or even inverted visual field 15. Perceptual Set a mental predisposition to perceive one thing and not another

4 o Ex. Adult Child pair look more alike when it is a parent-child. Once we have formed a wrong idea about reality, we have more difficulty seeing the truth Our existing schemas influence how we interpret ambiguous sensations with top-down processing Our facial recognition especially comes from the expressive eyes and mouth The context of a situation can allow our brain to work backwards in time, allowing a later stimulus to determine how we perceive an earlier one. Perceptual sets and contest show how experience helps us construct perception Perception is fed by sensation and cognition 16. Human Factors Psychology a branch of psychology that explores how people and machines interact and how machines and physical environments can be adapted to human behavior o Fit into our natural perceptions o Developers often suffer curse of knowledge and assume people will just know how to do their inventions o HF Psychologists strive to increase safety and productivity o Designers and engineers should consider the human factor 17. Extrasensory Perception (ESP) the controversial claim that perception can occur apart from sensory input. Said to include telepathy, clairvoyance, and precognition. 18. Parapsychology The study of the paranormal phenomena, including ESP and phychokinesis o Claims of ESP include astrological predictions, psychic healing, communication with the dead, and out of body experiences. Telepathy Mind-to-mind communication one person sending thoughts to another or perceiving another s thoughts. Clairvoyance Or perceiving remote events, such as sensing that a friends house is on fire Precognition or perceiving future events, such as a political leaders death or a sporting events outcome. Psychokineses mind over matter such as levitating a table or influencing the role of the dice. Accuracy of leading psychics has been meager Make vague predictions that later can be interpreted to match events Coincidences with dreams or predictions will astonish people o With enough time, the improbable becomes inevitable A reproducible ESP phenomenon has never been discovered nor has anyone produced any individual who can convincingly demonstrate psychic ability To give parapsychology credibility it needs a reproducible phenomenon and a theory to explain it.

5 These acts appear true in on stage demonstrations because the illusionist has control to manipulate and bewilder the audience o When placed in an experiment where they no longer have control, results cease to appear. Ganzfeld Procedure patients who were in a reclining chair with ping-pong balls over their eyes, white noise playing in the background, and red light bathing the room were able to more accurately match random images sent by an outside party.