Cognitive Psychology Fifth Edition Robert J Sternberg Chapter

Cognitive Psychology, Fifth Edition, Robert J. Sternberg Chapter 3 Ted talk: beau lotto: optical illusions 2009 Chapter 3: Visual Perception

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Some Questions of Interest • What is sensation vs. perception? • What are two fundamental approaches to explaining perception? • What happens when people with normal visual sensations cannot perceive visual stimuli?

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Distal vs. proximal stimuli • Light waves • Sound waves • Photon absorption • Conduction to • Chemical molecules • • • Pressure/vibration basilar membrane Absorption in olfactory epithelium Contact with taste buds Stimulation of dermis receptor cells

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Our Visual System Electromagnetic light energy is converted into neural electrochemical impulses

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Our Visual System Three main layers of retina – Ganglion cells – Amacrine cells, horizontal cells, bipolar cells – Photoreceptors • Rods and cones Chapter 3

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Visual Pathways in the Brain “what” • Temporal lobe lesions in monkeys – Can indicate where but not what “where” – Parietal lobe lesions in monkeys – Can indicate what but not where

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Sensation does not equal perception!

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Perceptual Basics • Sensory adaptation – Occurs when sensory receptors change their sensitivity to the stimulus • Our senses respond to change – Ganzfeld effect

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Perceptual Constancy • Object remains the same even though our sensation of the object changes – Size constancy vs. shape constancy

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Depth Perception – Monocular vs. binocular depth cues

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Monocular Depth Cues • Texture gradients – Grain of item • Relative size – Bigger is closer • Interposition • Closer are in front of other objects • Linear perspective – Parallel lines converge in distance • Aerial perspective – Images seem blurry farther away • Motion parallax – Objects get smaller at decreasing speed in distance

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Binocular Depth Cues • Binocular convergence • Binocular disparity

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Perceptual Illusions • Sometimes we cannot perceive what does exist • Sometimes we perceive things that do not exist • Sometimes we perceive what cannot be there

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Perceptual Illusions http: //www. michaelbach. de/ot/#history

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Visual illusions: brain function

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Theories of Perception • Bottom-up vs top down theories

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Bottom-Up Processing Theories • • Direct perception Template theories Feature-matching theories Recognition-by-components theory

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Gibson’s Theory of Direct Perception • The information in our sensory receptors is all we need – No complex thought processes • EX: Use texture gradients as cues for depth and distance • Mirror neurons start firing 30100 ms after a visual stimulus

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Template Theories compare to templates in memory until a match is found – Problem of imperfect matches

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Feature-Matching Theories • Recognize objects by features – Detect elements and assemble them into more complex forms – Brain cells respond to specific features • lines and angles

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Pandemonium Model • Four kinds of demons – Image demons – Feature demons – Cognitive demons – Decision demons

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Physiological Evidence for Features • Hubel & Wiesel (1979) – Simple cells – bars/edges – Complex cells – bars/edgesdetect bars of particular orientation – Hypercomplex cells -- particular colors (simple and complex cells), bars, or edges of particular length or moving in a particular direction

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Cog. Lab: Visual Search • Features vs. objects • The role of attention (next chapter)

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Top-Down Processing (Constructive Approach) • Perception is not automatic from raw stimuli – making inferences – guessing from experience

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 “Finished files are the result of years of scientific study combined with the experience of many years. ”

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Evidence for Top-Down Processing • Context effects

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Configural-Superiority Effect • Objects presented in context are easier to recognize than objects presented alone • Task: Spot the different stimuli, press button

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Configural-Superiority Effect Target Composite Measure reaction time Target alone = 1884 Composite = 749 Target spotted faster in a context!

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Gestalt’s View of Perception “The whole is more than a sum of its parts” • Law of Prägnanz –Individuals organize their experience in as simple, concise, symmetrical, and complete manner as possible

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Gestalt’s Principles of Visual Perception

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Gestalt’s Principles of Visual Perception • Figure-ground – Organize perceptions by distinguishing between a figure and a background • Proximity – Elements tend to be grouped together according to their nearness • Similarity – Items similar in some respect tend to be grouped together

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Gestalt’s Principles of Visual Perception • Continuity – Based on smooth continuity, which is preferred to abrupt changes of direction • Closure – Items are grouped together if they tend to complete a figure • Symmetry – Prefer to perceive objects as mirror images B A D C

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Pattern Recognition Systems • Feature analysis system – Recognize parts of objects – Assemble parts into wholes • Configurational system – Recognize larger configurations

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Evidence for Separate Systems • Tanaka & Farah (1993) – Participants studied • Faces and names • Pictures of homes and home owner’s names – At test, given only a piece of face (e. g. , nose), whole face, whole home, or a piece of the home (e. g. , window) • Asked to recall names

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Tanaka & Farah (1993) • People have more difficulty recognizing parts of faces than parts of houses

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Fusiform Gyrus in Temporal Lobe • pattern recognition – facial recognition – high expertise in any item (birds, cars) recognition – Expert individuation hypothesis

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Evidence for Separate Systems • Prosopagnosia – Inability to recognize faces after brain damage – Ability to recognize objects is intact • Associative agnosia – Difficulty with recognizing objects – Can recognize faces

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Deficits in Perception • Disruption of the “what” pathway – Agnosia: Inability to recognize and identify objects or people • Disruption of the “what” pathway – Simultagnosic • Normal visual fields, yet act blind • Perceives only one stimulus at a time—single word or object • Prosopagnosia • Inability to recognize faces, including one's own

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Visual Pathways in the Brain “what” • Temporal lobe lesions in monkeys – Can indicate where but not what “where” – Parietal lobe lesions in monkeys – Can indicate what but not where

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Deficits in Perception • Disruption of the “how” pathway – Optic ataxia • Cannot use vision to guide movement • Unable to reach for items

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Synesthesia Michael: “Flavors have shape, ” he started, frowning into the depths of the roasting pan. “I wanted the taste of this chicken to be a pointed shape, but it came out all round. … When I taste something with an intense flavor, ” Michael continued, “the feeling sweeps down my arm into my fingertips. I feel it—its weight, its texture, whether it’s warm or cold, everything. I feel it like I’m actually grasping something. ” (p. 4)

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Synesthesia Victoria: In response to a pager going off, said: “Oh, those blinding red jaggers! Turn that thing off, ” she snapped. … “Your beeper made me see three red lightning bolts, brilliant red going up to the left. ” She kept rubbing her head. “It’s usually not that strong, but it’s given me a splitting pain, ” she continued. (pp. 47 -48). “What makes you see things? ” I asked. “Give us some details. ” “Sharp, shrill sounds always do it, ” she said, “like your beeper, or ambulance sirens, crashes, screeching tires. ” … “Sudden sounds like that. Sometimes music will do it, if it’s loud enough and high enough in pitch, ” she continued. … “I once heard a Chihuahua who drove me crazy with the sound of white spikes. But that can’t be the correct explanation, because words and names sometimes have color too. ” (p. 48)

Cognitive Psychology, Sixth Edition, Robert J. Sternberg Chapter 3 Perceptual Illusions and “construction” • Phantom limb • synesthsia