2 Chapter 6 Perception The process of selecting, organizing, and interpreting sensory information, which enables us to recognize meaningful objects and events.

3 Selective Attention Perceptions about objects change from moment to moment. We can perceive different forms of the Necker cube; however, we can only pay attention to one aspect of the object at a time. Ex: Cocktail Party Phenomenon Necker Cube Experiment - Video

4 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. Daniel Simons, University of Illinois

5 Change Blindness Change blindness is a form of inattentional blindness in which a majority of individuals giving directions failed to notice a change in the individual asking for directions. © 1998 Psychonomic Society Inc. Image provided courtesy of Daniel J. Simmons. Experiment - Video

6 Perceptual Illusions Illusions provide good examples in understanding how perception is organized. Studying faulty perception is as important as studying other perceptual phenomena. Line AB is longer than line BC.

Illusions Physical Paradoxical/Perceptual 7

8 Perceptual Organization Visual Capture Vision vs. other senses? Vision usually wins GESTALT PSYCHOLOGY -A movement formed in Germany in the 1920s and ’30s -The study of how people organize the world visually into meaningful units and patterns. - “The whole is more important than the sum of the parts” - In other words, when we perceive something, properties emerge from the object that are not found in any particular component.

Gestalt: Form Perception People ALWAYS organize the visual field into 2 parts –___________: stands out from the rest of the environment –___________: the background

SOMETIMES… Your eyes have trouble distinguishing FIGURE and GROUND

GESTALT PRINCIPLES 1. _______________ –Things that are near each other, tend to be grouped together For Example…

GESTALT PRINCIPLES 2. Connectedness –In order to complete forms, the brain FILLS IN THE GAPS For Example…

GESTALT PRINCIPLES 3. _______________ –Things that are alike in some way (e.g. color, shape, size) tend to be perceived as belonging together For example…

GESTALT PRINCIPLES 4. _________________ –Lines and patterns tend to be perceived as continuing in time or space For Example…

24 Depth Perception Visual Cliff Depth perception enables us to judge distances. Gibson and Walk (1960) suggested that human infants (crawling age) have depth perception. Even newborn animals show depth perception. Innervisions

25 Binocular Cues Retinal disparity: Images from the two eyes differ. 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.

26 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.

27 Monocular Cues See Characteristics of Perception assignment we did in library and/or homework.

28 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. Two lights flashing one after the other. One light jumping from one point to another: Illusion of motion.

29 Perceptual Constancy Perceiving objects as unchanging even as illumination and retinal images change. Perceptual constancies include constancies of shape and size. Shape Constancy

30 Size Constancy Stable size perception amid changing size of the stimuli. Size Constancy

31 Size-Distance Relationship The distant monster (below, left) and the top red bar (below, right) appear bigger because of distance cues. From Shepard, 1990 Alan Choisnet/ The Image Bank

32 Size-Distance Relationship 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

33 Ames Room The Ames room is designed to demonstrate the size- distance illusion.

What is your perception of…

47 Perception: Nature or Nurture? Perceptual Interpretation: Restored Vision Blind adults w/ restored vision: could differentiate figure and ground relationships, but had difficulty distinguishing a circle and a triangle (Von Senden, 1932). Others struggled w/ facial recognition & expressions. Perceptual Interpretation: Sensory Deprivation Kittens raised without exposure to horizontal lines later had difficulty perceiving horizontal bars.

48 Perception: Nature or Nurture? Perceptual Adaptation Visual ability to adjust to an artificially displaced visual field, e.g., prism glasses. Courtesy of Hubert Dolezal

49 Perception: Nature or Nurture? Perceptual Set A mental predisposition to perceive one thing and not another. What you see in the center picture is influenced by flanking pictures. From Shepard, 1990.

50 (a) Loch ness monster or a tree trunk; (b) Flying saucers or clouds? Perception: Nature or Nurture? Perceptual Set Other examples of perceptual set. Frank Searle, photo Adams/ Corbis-Sygma Dick Ruhl

FILL IN THE FOLLOWING WORDS? 1. Goose4. Wager7. Bonnet Swan Gamble Derby D_ck B_t _at 2. Bear5. Sinful8. Shoot Wolf Evil Kill _ox B_d H_nt 3. Artist6. Courage9. Tractor Brush Brave Crops P_int _old _arm

FILL IN THE FOLLOWING WORDS 1. Sam4. Base7. Cat Pete Ball Mouse M_ke B_t _at 2. Package5. Pillow8. Help Carton Sheet Suggest _ox B_d H_nt 3. Needle6. Bend9. Hurt Sharp Crease Punish P_int _old _arm

53 Children's schemas represent reality as well as their abilities to represent what they see. Perception: Nature or Nurture? Schemas Schemas are concepts that organize and interpret unfamiliar information. Courtesy of Anna Elizabeth Voskuil

Schemas: Recognizing a Face 54

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57 Students recognized a caricature of Arnold Schwarzenegger faster than his actual photo. Features on a Face Face schemas are accentuated by specific features on the face. Kieran Lee/ FaceLab, Department of Psychology, University of Western Australia

58 Eye & Mouth Eyes and mouth play a dominant role in face recognition. Courtesy of Christopher Tyler

59 To an East African, the woman sitting is balancing a metal box on her head, while the family is sitting under a tree. Perception: Nature or Nurture? Cultural & Context Effects Context instilled by culture alters perception. What do you see in this picture?

67 Perception: Nature or Nurture? Perception = Biopsychosocial

68 Perception & Human Factors Human Factor Psychologists design machines that assist our natural perceptions. The knobs for the stove burners on the right are easier to understand than those on the left. Photodisc/ Punchstock Courtesy of General Electric

69 Is There Extrasensory Perception? Perception without sensory input is called extrasensory perception (ESP). A large percentage of scientists do not believe in 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.

70 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.

71 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.