Introductory Psychology: Sensation & Perception (Vision)

lecture 16 from a college level introduction to psychology course taught Fall 2011 by Brian J. Piper, Ph.D. ([email protected]) at Willamette University, includes anatomy of eye/brain, dorsal pathway, ventral pathway, figure/ground, many illusions, synesthesia

1. Sensation & Perception I: Vision Brian J. Piper, Ph.D.

2. Goals Sensation Perception Myth: Perception = Sensation Reality: Perception ≠ Sensation

3. Terminology Sensation : the process by which sensory receptors receives stimulus energy from our environment Perception : the process of organizing & interpreting sensory information

4. Psychophysics the study of the relationship between the physical characteristics of stimuli & our psychological experiences j nd : minimum difference a person can detect between two stimuli Weber’s Law: 2 stimuli must differ by a proportion (light: 8%, weight: 2%, tone: 0.3%) 1795-1878

5. Below jnd (Subliminal) A double-blind study had volunteers listen to tapes for 4 weeks (memory or self-esteem). Self-reported memory and self-esteem was measured before and after listening. Label Reality Memory Memory Memory Self-esteem Self-esteem Self-esteem Self-esteem Memory Greenwald et al. (1991). Psychological Science, 2, 119-122.

6. Predicted Results This study has four groups (Label/Material) Self-Esteem/Self-Esteem; Memory/Memory; Self-Esteem/Memory; Memory/Self-Esteem What impact, if any, will the labels have? In terms of Memory, please rank them from highest (best) to lowest. In terms of Self-Esteem, please rank them from highest to lowest. Greenwald et al. (1991). Psychological Science, 2, 119-122.

7. Interpretation Self-esteem and memory post-test were expressed as relative to pre-test. What discussion section would you write? Greenwald et al. (1991). Psychological Science, 2, 119-122.

8. Interpretation Self-esteem and memory post-test were expressed as relative to pre-test. What discussion section would you write? Greenwald et al. (1991). Psychological Science, 2, 119-122.

9. Interpretation Greenwald et al. (1991). Psychological Science, 2, 119-122. People that want to improve, improve. No benefits of subliminal messages consistent with their advertised intent.

10. Energy to Action Potentials http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html

11. Wave Properties Amplitude: height, small = dull; large = bright Wavelength : distance from peak to peak, determines color: b lue < green < red

12. Wavelength Different wavelengths of light result in different colors. 400 nm 700 nm Long wavelengths Short wavelengths Violet Indigo Blue Green Yellow Orange Red

13. The Eye

14. Parts of the eye Cornea: Transparent tissue where light enters the eye. Iris: Muscle that expands and contracts to change the size of the opening (pupil) for light. Lens: Focuses the light rays on the retina. Retina: Contains sensory receptors that process visual information and sends it to the brain.

15. Retina Retina: The light-sensitive inner surface of the eye, containing receptor rods and cones in addition to layers of other neurons (bipolar, ganglion cells) that process visual information.

16. Optic Nerve, Blind Spot & Fovea http://www.bergen.org Optic nerve: Carries neural impulses from the eye to the brain. Blind Spot: Point where the optic nerve leaves the eye because there are no receptor cells located there. Fovea : Central point in the retina around which the eye’s cones cluster.

17. Test your Blind Spot Use your textbook. Close your left eye, and fixate your right eye on the black dot. Move the page towards your eye and away from your eye. At some point the car on the right will disappear due to a blind spot.

18. Photoreceptors E.R. Lewis, Y.Y. Zeevi, F.S Werblin, 1969

19. Young-Helmholtz Trichromatic “Theory” Physician/Physicist Thomas Young & Hermann von Helmholtz predicted that the eye would have three kinds of color receptors. 1773-1829 1821-1894 “Whoever in the pursuit of science, seeks after immediate practical utility may rest assured that he seeks in vain.”

20. C o l o r B l i n d n e s s Ishihara Test Genetic disorder in which people are blind to green or red colors. This supports the Trichromatic specialization of cones.

21. Visual Information Processing Optic nerves connect to the thalamus in the middle of the brain, and the thalamus connects to the visual cortex.

22. Feature Detection Nerve cells in the visual cortex respond to specific features, such as edges, angles, and movement. Ross Kinnaird/ Allsport/ Getty Images

23. Visual Information Processing Processing of several aspects of the stimulus simultaneously is called parallel processing . The brain divides a visual scene into subdivisions such as color, depth, form, movement, etc.

24. Dorsal & Ventral Streams

25. Edgar Rubin Figure/Ground

26. Sandro Del- Prete : “Message d’Amour des Dauphins” 1987

27. Grouping & Reality Although grouping principles usually help us construct reality, they may occasionally lead us astray. Both photos by Walter Wick. Reprinted from GAMES Magazine. .© 1983 PCS Games Limited Partnership

28. Which one is continuation? Johann Christian Poggendorff

29. Parallel Lines? Ewald Hering

30. Parallel Lines?  Johann Karl Friedrich Zöllner

31. 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

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.

34. Which one is bigger? Ponzo Illusion

35. Which one is bigger? Ponzo Illusion

36. Which one is bigger? Ponzo Illusion http://www.youtube.com/watch?v=hdZHfzjJf-g

37. Which one is bigger? Ebbinghaus Illusion Hermann Ebbinghaus 1850-1909

38. Volunteer?

39. Volunteer? Aoccdrnig to rscheearch at Cmabrigde Uinervtisy , it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoatnt tihng is taht the frist and lsat ltteer be at the rghit pclae . The rset can be a toatl mses and you can sitll raed it wouthit a porbelm . Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef , but the wrod as a wlohe .

40. Compare Darkness Edward H. Adelson Checker Shadow Illusion

41. Compare Darkness Edward H. Adelson Checker Shadow Illusion

42. Compare Darkness Edward H. Adelson Checker Shadow Illusion

43. How many colors do you see?

44. Number-Color Synesthesia V.S. Ramachandran 1951-

45. Number-Color Synesthesia

46. Static Image I: Akiyoshi Kitaoka

47. Static Image II: Akiyoshi Kitaoka

48. Mars Surface: Viking I-1976

49. Devil?

50. Not Politically Correct

51. Eye-tracking

52. “Fusiform Facial Area”

53. Prosopagnosia Inability to recognize faces Sensation without Perception Video Worth -> Sensation & Perception

54. Selective Attention http:// www.youtube.com/watch?v=vJG698U2Mvo http:// www.youtube.com/watch?v=Ahg6qcgoay4

55. Floating Cube http://www.youtube.com/user/Rxe08?blend=8&ob=5

56. Street Art http://www.youtube.com/watch?v=8r26AwT7PTM West Vancouver (15 sec):

57. Summary Perception > Sensation Retina -> Optic Nerve -> Thalamus -> Visual Cortex -> Beyond Illusions: Figure ground Faces “Motion” Impossible