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PSYCHOLOGY (8th Edition) David Myers PowerPoint Slides Aneeq Ahmad Henderson State University Worth Publishers, 2006 1 Slide 2 Perception Chapter 6 2 Slide 3 Perception Group Experiment Selective Attention Perceptual Illusions Perceptual Organization Form Perception Motion Perception Perceptual Constancy 3 Slide 4 Perception Perceptual Interpretation Sensory Deprivation and Restored Vision Perceptual Adaptation Perceptual Set Perception and Human Factor 4 Slide 5 Perception Is there Extrasensory Perception? Claims of ESP Premonitions or Pretensions Putting ESP to Experimental Test 5 Slide 6 Perception The process of selecting, organizing, and interpreting sensory information, which enables us to recognize meaningful objects and events (Top down processing). 6 Slide 7 ACTIVITY DO NOT LOOK AT THE PRINTED WORDS!! Fold your paper vertically so the left side is visible and the right side is not Select the five words that BEST describe YOU by placing a check to the left of the word What does the activity show about perception? 7 Slide 8 8 Slide 9 Selective Attention Perceptions about objects change from moment to moment. We can perceive different forms of the Necker cube (below); however, we can only pay attention to one aspect of the object at a time. Other examples: the Stroop Task, dichotic listening) 9 Necker Cube Slide 10 Stroop Task 10 Slide 11 GREENYELLOWBLUE YELLOWGREEN BLUE RED Slide 12 STROOP TASK Green Red Blue Purple Blue Purple Blue Purple Red Green Purple Green 12 Slide 13 SELECTIVE ATTENTION Stress narrows attention OTHER EXAMPLES: Cell phones in car ? 13 Slide 14 How many times is the ball passed? http://www.youtube.com/watch?v=vJG6 98U2Mvohttp://www.youtube.com/watch?v=vJG6 98U2Mvo 14 Slide 15 Inattentional Blindness Inattentional blindness refers to the inability to see an object or a person in our midst. Simmons & Chabris (1999) showed that half of the observers failed to see the gorilla-suited assistant in a ball passing game.. 15 Daniel Simons, University of Illinois Slide 16 Change Blindness http://www.youtube.com/watch?v=- HVw9kWkPX0http://www.youtube.com/watch?v=- HVw9kWkPX0 16 Slide 17 Change Blindness Change blindness is a form of inattentional blindness in which two-thirds of individuals giving directions failed to notice a change in the individual asking for directions. 17 1998 Psychonomic Society Inc. Image provided courtesy of Daniel J. Simmons. Slide 18 INATTENTIONAL BLINDNESS CHANGE DEAFNESS CHOICE BLINDNESS CHOICE BLINDNESS BLINDNESS 18 Slide 19 POP-OUT, opposite of inattentional blindness A STRIKINGLY DISTINCT STIMULUS AUTOMATICALLY DRAWS OUR EYE: accomplished by parallel processing 19 Slide 20 ATTENTION Give an example of each Attentional resources are limited Attention can be divided Attention requires effort. Attention improves mental processing Control of attention can be voluntary or involuntary 20 Slide 21 ATTENTION Overt vs covert orienting Overt: pointing sensory systems at a particular stimulus Example? Covert: Shifting attention without the appearance of shifting the sensory system Example? 21 Slide 22 Perceptual Illusions 22 Illusions provide good examples in understanding how perception is organized. Studying faulty perception is as important as studying other perceptual phenomena. Muller- Lyer Illusion: Line AB is longer than line BC. Slide 23 Tall Arch 23 In this picture, the vertical dimension of the arch looks longer than the horizontal dimension. However, both are equal. Rick Friedman/ Black Star Slide 24 Illusion of a Worm 24 The figure on the right gives the illusion of a blue hazy worm when it is nothing else but blue lines identical to the figure on the left. 1981, by permission of Christoph Redies and Lothar Spillmann and Pion Limited, London Slide 25 3-D Illusion 25 It takes a great deal of effort to perceive this figure in two dimensions. Reprinted with kind permission of Elsevier Science-NL. Adapted from Hoffman, D. & Richards, W. Parts of recognition. Cognition, 63, 29-78 Slide 26 Sidewalk Art http://www.youtube.com/watch?v=fKJ0KY nB5R8 26 Slide 27 Perceptual Organization When vision competes with our other senses, vision usually wins a phenomena called visual capture. How do we form meaningful perceptions from sensory information? We organize it. Gestalt psychologists showed that a figure formed a whole different than its surroundings: the whole is greater than the sum of its parts . 27 Slide 28 PERCEPTUAL ORGANIZATION Sensation (bottom up processing) and Perception (top down processing) blend into one continuous process Fundamental point: We constantly filter sensory information and infer perceptions in ways that make sense to us. Mind matters. 28 Slide 29 Form Perception Organization of the visual field into objects (figures) that stand out from their surroundings (ground). Another example: cocktail party phenomena 29 Time Savings Suggestion, 2003 Roger Sheperd. Slide 30 30 Slide 31 31 Slide 32 32 Slide 33 REVERSIBLE FIGURE GROUND Reversible figure- ground illusions demonstrate that the same stimulus can trigger more than one perception. 33 Slide 34 Grouping 34 After distinguishing the figure from the ground, our perception needs to organize the figure into a meaningful form using grouping rules. Slide 35 GESTALT GROUPING PRINCIPLES graphicdesign.spokanefalls.edu/tutorials/p rocess/gestaltprinciples/gestaltprinc.htm 35 Slide 36 GROUPING FIRST IMPRESSIONS _____1. Sometimes interviewers focus on one trait to the A. gestalt exclusion of others; this one trait, good or bad, is dominant against the background of other traits. _____2. The purpose of this interview, Sarah was told, isB. similarity to gather bits and pieces of information about you so that I might form an overall, meaningful picture of you. _____3. Sometimes applicants are compared to other C. proximity applicants who are the same age, gender, race, education, and so on. Interviewers have to avoid this tendency because it prevents their seeing the person as an individual. _____4. John sees the whole interview process as one, long continuousD. continuity stream of asking questions and gathering information. _____5. Mrs. Thatcher tends to group interviewees together into her E figure-ground morning applicants, afternoon applicants, and drop-ins, depending on who comes in with whom during the course of a days appointments. 36 Slide 37 Grouping & Reality Although grouping principles usually help us construct reality, they may occasionally lead us astray. 37 Both photos by Walter Wick. Reprinted from GAMES Magazine.. 1983 PCS Games Limited Partnership Slide 38 OTHER GROUPING PRINCIPLES LIKLIHOOD PRINCIPLE: we tend to perceive objects in the way that experience tells us is the most likely physical arrangement Auditory scene analysis Sound localization Visual capture 38 Slide 39 Depth Perception Depth perception enables us to judge distances. Gibson and Walk (1960) suggested that human infants (crawling age) have depth perception. Depth perception appears to be innate, amplified by experience 39 Visual Cliff Innervisions Slide 40 DEPTH PERCEPTION Two dimensional images fall on our retina, how do we see three dimensionally? Depth perception (seeing objects in three dimensions) allows us to judge distance 40 Slide 41 RETINAL DISPARITY Note on the diagram how each eye sees the object from a different angle Retinal disparity = binocular disparity 41 Slide 42 42 Slide 43 Binocular Cues Retinal disparity: Images from the two eyes differ. Brain compares these images, their differences provide cues to relative distance of different objects Try looking at your two index fingers when pointing them towards each other half an inch apart and about 5 inches directly in front of your eyes. You will see a finger sausage as shown in the inset. 43 Slide 44 Binocular Cues Convergence: Neuromuscular cues. When two eyes move inward (towards the nose) to see near objects and outward (away from the nose) to see faraway objects. Accomodation muscles surrounding the lens tightening 44 Slide 45 45 Slide 46 BINOCULUAR CUES Hole in the Hand roll a sheet of paper into a tube and raise it to your right eye like a telescope. Look through it, focusing on a blank wall in front of you. Hold open left hand beside the tube and continue to focus ahead The images received by the two eyes will fuse and the hole in the tube will appear to be in your hand! 46 Slide 47 MONOCULAR CUES: RETINAL SIZE Go to the classroom window and estimate the size of a distant object, say a car. Return to your seat and draw a line the length of which produces the same-size retinal image that the object did. Then, go to the window, hold up a thumb to measure the object. Next return to your seat and measure your line with your thumb 47 Slide 48 WINDOW EXERCISE ON RETINAL How did your first estimate compare to the actual size? 48 Slide 49 Monocular Cues Relative Size: If two objects are similar in size, we perceive the one that casts a smaller retinal image to be farther away. 49 Slide 50 Monocular Cues Interposition: Objects that occlude (block) other objects tend to be perceived as closer. 50 Rene Magritte, The Blank Signature, oil on canvas, National Gallery of Art, Washington. Collection of Mr. and Mrs. Paul Mellon. Photo by Richard Carafelli. Slide 51 Monocular Cues 51 Relative Clarity: Because light from distant objects passes through more light than closer objects, we perceive hazy objects to be farther away than those objects that appear sharp and clear. Slide 52 Monocular Cues Texture Gradient: Indistinct (fine) texture signals an increasing distance. 52 Eric Lessing/ Art Resource, NY Slide 53 Monocular Cues Relative Height: We perceive objects that are higher in our field of vision to be farther away than those that are lower. 53 Image courtesy of Shaun P. Vecera, Ph. D., adapted from stimuli that appered in Vecrera et al., 2002 Slide 54 Monocular Cues Relative motion: Objects closer to a fixation point move faster and in opposing direction to those objects that are farther away from a fixation point, moving slower and in the same direction. 54 Slide 55 Monocular Cues Linear Perspective: Parallel lines, such as railroad tracks, appear to converge in the distance. The more the lines converge, the greater their perceived distance. 55 The New Yorker Collection, 2002, Jack Ziegler from cartoonbank.com. All rights reserved. Slide 56 Monocular Cues Light and Shadow: Nearby objects reflect more light into our eyes than more distant objects. Given two identical objects, the dimmer one appears to be farther away. 56 From Perceiving Shape From Shading by Vilayaur S. Ramachandran. 1988 by Scientific American, Inc. All rights reserved. Slide 57 Motion Perception Motion Perception: Objects traveling towards us grow in size (looming) and those moving away shrink in size. The same is true when the observer moves to or from an object. Evolutionary importance of detecting movement: wiggle your finger demo 57 Slide 58 Apparent Motion Phi Phenomenon: When lights flash at a certain speed they tend to present illusions of motion. Neon signs use this principle to create motion perception. 58 Two lights flashing one after the other. One light jumping from one point to another: Illusion of motion. Slide 59 Perceptual Constancy Perceiving objects as unchanging even as illumination and retinal images change. Brain needs to recognize the object without being deceived by changes. Perceptual constancies include constancies of shape and size. 59 Shape Constancy Slide 60 Perceptual Constancy Hold a hand in front of you at arms length and move it toward your head, then away; there will be no perceived change in size. However, retinal image size is changing. How can we detect? Hold forefinger of left hand about 8 inches in front of your face and focus on it Now position your right hand at arms length past your left forefinger. While maintaining fixation on left fingertip, move your right hand toward and away from your face. Focus on finger, but also notice image of the hand as it moves. It will change dramatically in size 60 Slide 61 Size Constancy Stable size perception amid changing size of the stimuli. 61 Size Constancy Slide 62 Size-Distance Relationship The distant monster (below, left) and the top red bar (below, right) appear bigger because of distance cues. Cultural experience also influences. 62 From Shepard, 1990 Alan Choisnet/ The Image Bank Slide 63 Size-Distance Relationship 63 Both girls in the room are of similar height. However, we perceive them to be of different heights as they stand in the two corners of the room. Both photos from S. Schwartzenberg/ The Exploratorium Slide 64 Ames Room 64 The Ames room is designed to demonstrate the size- distance illusion. Slide 65 Lightness Constancy 65 The color and brightness of square A and B are the same. Depends on relative luminance - the amount of light an object reflects relative to its surroundings. Courtesy Edward Adelson Slide 66 Color Constancy Perceiving familiar objects as having consistent color even when changing illumination filters the light reflected by the object. 66 Color Constancy Slide 67 COLOR CONSTANCY http://www.cnn.com/2009/OPINION/10/ 26/lotto.optical.illusions/index.htmlhttp://www.cnn.com/2009/OPINION/10/ 26/lotto.optical.illusions/index.html 67 Slide 68 Perceptual Interpretation Immanuel Kant (1724-1804) maintained that knowledge comes from our inborn ways of organizing sensory experiences. John Locke (1632-1704) argued that we learn to perceive the world through our experiences. 68 How important is experience in shaping our perceptual interpretation? Slide 69 Restored Vision After cataract surgery, blind adults were able to regain sight. These individuals could differentiate figure and ground relationships, yet they had difficulty distinguishing a circle and a triangle. (Von Senden, 1932). 69 Slide 70 Facial Recognition After blind adults regained sight, they were able to recognize distinct features, but were unable to recognize faces. Normal observers also show difficulty in facial recognition when the lower half of the pictures are changed. 70 Courtesy of Richard LeGrand Slide 71 Sensory Deprivation Kittens raised without exposure to horizontal lines later had difficulty perceiving horizontal bars. Influence of critical periods shown. 71 Blakemore & Cooper (1970) Slide 72 Perceptual Adaptation Visual ability to adjust to an artificially displaced visual field, e.g., prism glasses. Stratton experiment with optical headgear. 72 Courtesy of Hubert Dolezal Slide 73 PECEPTUAL ADAPTATION Form groups of four or five. Pick up a set of goggles and a ball. Assign roles: catcher, pitcher, subject (rotate roles) 73 Slide 74 Problems with Schemas 74 (Allport & Postman, 1947) Slide 75 PERCEPTUAL SET Our Whisper Down the Lane example was based on Allport and Postmans 1947 study Story was altered to fit the social expectations and stereotypes of the subjects. Three major perceptual distortions in transmission of information: 75 Slide 76 Allport and Postman LEVELING - perceiver drops certain details because they dont fit SHARPENING - details consistent with values and interests are emphasized ASSIMILATION - padding and organization used to make central theme fit subjects expectations 76 Slide 77 Perceptual Set A mental predisposition to perceive one thing and not another. What you see in the center picture is influenced by flanking pictures. Whisper Down the Lane example. 77 From Shepard, 1990. Slide 78 Perceptual Set 78 (a) Loch ness monster or a tree trunk; (b) Flying saucers or clouds? Other examples of perceptual set. Frank Searle, photo Adams/ Corbis-Sygma Dick Ruhl Slide 79 Other Examples of Perceptual Set Provide punctuation that will make the words meaningful: TIME FLIES I CANT THEYRE TOO FAST! 79 Slide 80 EXPLANATION Apostrophes come easily, but the rest is difficult. Were too familiar with the slogan. Think of time as a verb rather than a noun. Now it makes sense! 80 Slide 81 PERCEPTUAL SET What determines perceptual set? Through experience we form concepts, or schemas, that organize and interpret unfamiliar information. Example: a child s simplified drawing of people Our innate schemas for faces primes us; we are especially attuned to the eyes and mouth 81 Slide 82 Schemas 82 Children's schemas represent reality as well as their abilities to represent what they see. Schemas are concepts that organize and interpret unfamiliar information. Courtesy of Anna Elizabeth Voskuil Slide 83 Features on a Face 83 Students recognized a caricature of Arnold Schwarzenegger faster than his actual photo. Face schemas are accentuated by specific features on the face. Kieran Lee/ FaceLab, Department of Psychology, University of Western Australia Slide 84 Eye & Mouth 84 Eyes and mouth play a dominant role in face recognition. Courtesy of Christopher Tyler Slide 85 Cultural Context 85 To an East African, the woman sitting is balancing a metal box on her head, while the family is sitting under a tree. Context instilled by culture also alters perception. Slide 86 Perception Revisited 86 Is perception innate or acquired? Slide 87 Perception & Human Factors Human Factor Psychologists design machines that assist our natural perceptions. 87 The knobs for the stove burners on the right are easier to understand than those on the left. Photodisc/ Punchstock Courtesy of General Electric Slide 88 Human Factors & Misperceptions Understanding human factors enables us to design equipment to prevent disasters. 88 Two-thirds of airline crashes caused by human error are largely due to errors of perception. Slide 89 Human Factors in Space To combat conditions of monotony, stress, and weightlessness when traveling to Mars, NASA engages Human Factor Psychologists. 89 Transit Habituation (Transhab), NASA Slide 90 HUMAN FACTORS PSYCHOLOGY Examples of poor design? Why do experts often come up with poor solutions? Curse of knowledge the mistaken assumption that others share our expertise and will behave as we would Fail to schedule user-testing to reveal perception-based problems prior to production and distribution Why is this topic important? 90 Slide 91 Is There Extrasensory Perception? Perception without sensory input is called extrasensory perception (ESP). A large percentage of scientists do not believe in ESP. PARAPSYCHOLOGY: THE STUDY OF PARANORMAL PHENOMENON. 91 Slide 92 Claims of ESP Paranormal phenomena include astrological predictions, psychic healing, communication with the dead, and out-of-body experiences, but most relevant are telepathy, clairvoyance, and precognition. 92 Slide 93 Claims of ESP 1. Telepathy: Mind-to-mind communication. One person sending thoughts and the other receiving them. 2. Clairvoyance: Perception of remote events, such as sensing a friend s house on fire. 3. Precognition: Perceiving future events, such as a political leader s death. 93 Slide 94 Premonitions or Pretensions? Can psychics see the future? Can psychics aid police in identifying locations of dead bodies? What about psychic predictions of the famous Nostradamus? The answers to these questions are NO! Nostradamus predictions are retrofitted to events that took place after his predictions. 94 Slide 95 Putting ESP to Experimental Test In an experiment with 28,000 individuals, Wiseman attempted to prove whether or not one can psychically influence or predict a coin toss. People were able to correctly influence or predict a coin toss 49.8% of the time. 95 Slide 96 ESP CLAIMS To give ESP credibility, you would need: A reproducible phenomenon and a theory to explain it 96 Slide 97 97 Population Representative Sample ( larger the better) Experimental Group Control Group Apply Methods of control Apply methods of control Independent Variable Placebo Measure Dependent Variable Is the difference statistically significant? Random Assignment Everyone has equal chance. Random Sampling (aka Random Selection) This is the goal! EXPERIMENTAL DESIGN = Slide 98 QUASI EXPERIMENT: Not a true experiment No random assignment The independent variable already exists in the population (age, gender, etc) IV could be continuous (e.g. age) or categorical (e.g. gender) We can never be sure the quasi iv is causing the change in the dv or if another third factor can explain the difference 98 Slide 99 PERCEPTION EXPERIMENT Step One: Brainstorm ideas for an experiment. Remember: develop an idea based on a perceptual concept. Develop a hypothesis, with an independent variable and dependent variable. A good format for your hypothesis: If ________, then _____. Operationally define variables. 99 Slide 100 INTRODUCTION Why Am I Doing This Study? You will need to research your topic for the Introduction (review of past research, justify the logic of the study, and presenting your hypothesis) Check your textbook for background information. You need to cite two additional sources in your Introduction. Introduction: two pages double spaced; all sources must be cited using APA style Hypothesis with iv, dv, and operational definitions 100 Slide 101 METHOD What Did I Do? All ethical guidelines must be followed! Based on your description of the apparatus and procedures could someone replicate your experiment? Have separate sections labeled: Subjects (include description of population and method of selection), Procedures (you may number this), Materials and Apparatus 101 Slide 102 CONSENT FORM..\AP Notes\Perception\Consent Form for Experiment.doc..\AP Notes\Perception\Consent Form for Experiment.doc Fill the consent form out as a group to insure uniformity. Make enough copies to give each subject a copy and to keep a copy for yourself. Be prepared to hand these in if I request you to do so. 102 Slide 103 RESULTS What Did I Find? Graphs, charts, tables that present an analysis of your findings. You do NOT interpret the results in this section. You do not present the raw data here, but you should include it in an Appendix if required. 103 Slide 104 DISCUSSION - What is the Significance of My Findings? You relate your findings to your hypothesis and the theories you investigated. Did you support your hypothesis? A null hypothesis is one where no effect is expected. You may need to explain why you did not get the results you expected. Were there confounding variables, experimenter bias, etc.? Identify new or additional questions raised by your study. 104 Slide 105 REFERENCES How Do I Give Credit Where Credit Is Due? Requirement: two sources in addition to textbook You need to use the APA style for your citations and reference page Place appropriate citations in the paper as well as including a reference page. It is better to overcite than to undercite. 105 Slide 106 APA STYLE CITATION EXAMPLES: the effects of unchecked infections accumulate (Neese, 1991) Carrie Armel and Vilayanur Ramachandran (2003) cleverly illustrated. 106 Slide 107 APA STYLE Reference Page Examples: Journal: Murzynski, J. (1996). Body language of women. Journal of Applied Social Psychology, 26, 1617 1626. Book: Paloutzian, R. F. (1996). Invitation to the psychology of religion. (2 nd ed.). Boston: Allyn and Bacon. Online: Nielsen, M.E. Notable people in psychology. Retrieved August 3, 2005, from http://www. psywww.comhttp://www Encyclopedia Shea, J.D. (2004) Depression and Adjustment. In J.F. Schumaker (Ed), Encyclopedia of Mental Health (pp. 70-84). New York: Oxford /University Press. 107 Slide 108 APPENDIX If necessary, this might include: Copies of surveys, pictures, etc used as materials Raw data 108 Slide 109 ABSTRACT Complete last, but place first. Single spaced Short summary; include one or two sentences from each section: Introduction, Methodology, Results, Discussion 109