1. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved PowerPoint Presentations for Philip G. Zimbardo Robert L. Johnson Vivian McCann Prepared by Beth M. Schwartz Randolph College This multimedia product and its contents are protected under copyright law. The following are prohibited by law: any public performance or display, including transmission of any image over a network; preparation of any derivative work, including the extraction, in whole or part, of any images; any rental, lease, or lending of the program. Seventh Edition

2. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved This multimedia product and its contents are protected under copyright law. The following are prohibited by law: any public performance or display, including transmission of any image over a network; preparation of any derivative work, including the extraction, in whole or part, of any images; any rental, lease, or lending of the program. Chapter 3 Sensation & Perception

3. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Sensation and Perception Sensation A process by which a simulated receptor create a pattern of neural messages that represent the stimulus in the brain Perception A process that makes sensory patterns meaningful

4. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved The brain senses the world indirectly because the sense organs convert stimulation into the language of the nervous system: neural messages. How Does Stimulation Become Sensation?

5. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Transduction Transduction Converts a form of physical energy into the form of neural messages Sensory Receptors Specialized neurons that are activated by stimulation and transduce (convert) the incoming stimulus into electrochemical signals

6. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Stimulation Becomes Perception Figure 3.1 Stimulation Becomes Perception For visual stimulation to become meaningful perception, it must undergo several transformations. First, physical stimulation (light waves from the butterfly) is transduced by the eye, where information about the wavelength and intensity of the light is coded into neural signals. Second, the neural messages travel to the sensory cortex of the brain, where they become sensations of color, brightness, form, and movement. Finally, the process of perception interprets these sensations by making connections with memories, expectations, emotions, and motives in other parts of the brain. Similar processes operate on the information taken in by the other senses.

7. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Transduction Sensory Pathway Bundles of neurons that carry information from the sense organs to the brain

8. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Thresholds Absolute Threshold Amount of stimulation necessary for a stimulus to be detected Difference Threshold Smallest amount by which a stimulus can be changed and the difference be detected (also called just noticeable difference: JND)

9. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Approximate Sensory Thresholds of Five Senses

10. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Thresholds Weber’s Law The size of the JND is proportional to the intensity of the stimulus. The JND is always large when the stimulus intensity is high, and small when the stimulus intensity is low.

11. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Signal Detection Theory Sensation depends on the characteristics of the stimulus, the background information, and the detector. Stimulus event Neural activity Comparison with personal standard Action (or no action)

12. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved The senses all operate in much the same way, but each extracts different information and sends it to its own specialized processing region in the brain. How Are the Senses Alike? How Are They Different?

13. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Fundamental Features of the Human Senses

14. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved The Anatomy of Visual Sensation

15. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Transduction of Light in the Retina

16. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved How Visual Stimulation Goes from the Eyes to the Brain

17. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved How the Visual System Creates Color and Brightness Wavelength Color Intensity (amplitude) Brightness

18. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved How the Visual System Creates Color Electromagnetic Spectrum Entire range of electromagnetic energy; includes radio waves, X-rays, microwaves, and visible lightEntire range of electromagnetic energy; includes radio waves, X-rays, microwaves, and visible light Visible Spectrum Tiny part of the electromagnetic spectrum that is visible to our eyesTiny part of the electromagnetic spectrum that is visible to our eyes

19. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved The Light Stimulus

20. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved How the Visual System Creates Color Trichromatic Theory Based on three different cone receptors Explains initial stages of color sensation Opponent-Process Theory Based on bipolar cells Colors in complementary pairs Explains afterimages

21. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Afterimages Afterimages Sensations that linger after the stimulus is removed In the following slide, fix your eyes on the dot in the center of the flag.

22. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved

23. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved How the Visual System Creates Color Color Blindness Vision disorder that prevents an individual from discriminating certain colors

24. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Ishihara Color Blindness Test

25. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Sound Waves

26. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved How We Hear Sound Waves Cochlea

27. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Auditory Stimulation Becomes Sensation

28. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Psychological Qualities of Sounds Pitch Sensory characteristic of sound produced by the frequency of the sound wave Loudness Sensory characteristic of sound produced by the amplitude (intensity) of the sound wave Timbre Quality of a sound wave that derives from the wave’s complexity

29. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Decibel Levels of Different Sounds

30. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Position and Movement Vestibular Sense Sense of body orientation with respect to gravity receptors in semicircular canals Kinesthetic Sense Sense of body position and movement of body parts relative to each other receptors in joints, muscles, and tendons

31. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Smell Olfaction Sense of smell Olfactory Bulbs Brain sites of olfactory processing Pheromones Chemical signals released by organisms to communicate with other members of the species

32. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Receptors for Smell

33. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Receptors for Taste

34. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved The Skin Senses The skin protects against surface injury, holds in bodily fluid, and helps regulate body temperature. Touch Warmth Cold Texture Pain

35. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Pain Arises from intense stimulations Nociceptors (nerve cells) sense painful/unpleasant stimuli. affected by mood and expectation Phantom Limb An amputee feels sensations coming from missing the body part due to the brain generating sensation. Gate Control Theory Explains pain control Involves special interneurons that open or close the pain pathway running up the spinal cord toward the brain

36. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Dealing with Pain Analgesic Drugs Aspirin: interferes with chemical signal Morphine: suppresses pain messages Psychological Techniques Placebo: mock drug Placebo effect: change caused by the belief that one is taking a real drug

37. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Perception brings meaning to sensation; therefore perception produces an interpretation of the external world, not a perfect representation of it. What is the Relationship Between Perception and Sensation?

38. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved What is the Relationship Between Perception and Sensation? Percept Meaningful product of a perception Pathways in the Brain What pathway: temporal lobe Where pathway: parietal lobe

39. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved The Machinery of Perceptual Processing Feature Detectors Cells in the cortex that specialize in detection of specific stimulus features Binding Problem Unsolved mystery concerning the processes used by the brain to combine many aspects of sensation into a single percept

40. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Two Complementary Processes Bottom-Up Processing Analysis that emphasizes characteristics of the stimulus Top-Down Processing Emphasizes the perceiver’s expectations, memories, and other cognitive factors

41. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Perceptual Constancies Perceptual Constancy Ability to recognize the same object under different conditions, such as changes in illumination, distance, or location color constancy size constancy shape constancy

42. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Shape Constancy

43. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Perceptual Ambiguity and Distortion Illusions Demonstrably incorrect experience of a stimulus pattern; shared by others in the same perceptual environment Ambiguous Figures Images that allow for more than one interpretation

44. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved What Is Depicted Here?

45. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Perceptual Illusions

46. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Perceptual Illusions The Herman Grid Do you see small gray squares between the black squares?

47. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Six Illusions to Tease Your Brain

48. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Theoretical Explanations for Perception Gestalt Psychology States that much of perception is shaped by innate factors built into the brain Figure Part of a pattern that commands attention Ground Part of a pattern that does not command attention; the background

49. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved The Gestalt Laws of Perceptual Grouping Similarity Proximity Continuity Common fate Prägnanz

50. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Gestalt Laws of Perceptual Grouping

51. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Law of Prägnanz

52. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved The Gestalt Approach Subjective Contours Boundaries that are perceived but do not appear in the stimulus pattern Closure Tendency to fill in gaps in figures and see incomplete figures as complete

53. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Subjective Contours & Closure

54. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Theoretical Explanations for Perception Learning-Based Inference View that perception is primarily shaped by prior learning and experience Perceptual Set Readiness to detect a particular stimulus in a given context

55. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Cultural Influences on Perception Which box is bigger, A or B?

56. Copyright © Allyn and Bacon 2006Copyright © 2012 Pearson Education, Inc. All Rights Reserved Depth Perception Nature or Nurture? Visual Cliff Experiment Illustrates the developmental age at which depth is perceived Binocular Cues Depend on information taken in by both eyes Monocular Cues Depend on information taken in by only one eye