1. Sensation and Perception: How the World Enters the Mind

2. Sensation and Perception
The awareness of properties of an object or event when a sensory receptor is stimulated
Perception
The act of organizing and interpreting sensory input as signaling a particular object or event

3. Illusions When perception does not accurately represent the world
Note to instructor: This is a demo and the slide will change with each click.

4. Psychophysics
Study of the relationship between physical events and the corresponding experience of those events
Thresholds
Absolute threshold
Just-noticeable difference (JND)
Weber’s law

5. Psychophysics: Detecting Signals
Signal detection theory
A “signal” is always embedded in noise
Sensitivity
Threshold level for distinguishing signal from noise
Bias
Willingness to report noticing a stimulus
Yes No
Reported signal?
Signal?
Yes No
Hit
Miss
False
alarm
Correct
rejection

6. Detecting Light
Properties of light
Amplitude
Frequency
Wavelength

7. Structures of the Eye
Pupil
Iris
Cornea
Retina
Fovea
Optic nerve

8. Rods and Cones Rods (100-120 million) Cones (5-6 million)
Very sensitive to light
Only register shades of gray
Not in fovea
Cones (5-6 million)
Sensitive to particular wavelengths
Produce color vision
Denser near fovea

9. Visual Processes Transduction Accommodation Dark adaptation
Filling in the blanks
Do the blind spot demo in Figure 4.6

10. Detecting Color Properties of color Hue Saturation Lightness
Differing wavelengths
Saturation
Purity of input (amount of white that is “mixed in”)
Lightness
Amplitude of waves

11. Color Vision Trichromatic theory Opponent process theory Afterimage
Opponent cells
Color blindness

12. Seeing Afterimages In the following slide, fix your eyes
on the dot in the center of the flag

15. Vision Problems Common visual problems Myopia (nearsightedness)
Hypermetropia (farsightedness)
Astigmatism
Cataract
Macular degeneration

16. Organizing the Visual World
Perceptual organization
Figure-ground

17. Gestalt Laws of Organization
Proximity
XXX XXX vs. XX XX XX
Continuity
_ _ _ _ vs. _ _ _ - - -
Similarity
XXXxxx
Closure
Good form
[ ] vs. [ _

18. Ambiguous Figures

19. Perceptual Constancies
Size constancy
Shape constancy
Color constancy

20. Knowing the Distance
Problem: The 3-D world is projected onto a 2-D retina.
How do you construct a 3-D perception based on 2-D retinal images?
Visual cues

21. Knowing the Distance Visual cues Static cues Motion cues
Binocular cues
Retinal disparity
Convergence
Monocular cues
Texture gradient
Motion cues
Motion parallax

22. Visual Perception: Pathways
“Where” pathway – parietal lobe
“What” pathway – temporal lobe

23. Knowing More Than You Can See
Top-down processing
Bottom-up processing
Perceptual set
B E F R
B E F R
Note to instructor: This is a demo and the slide will change with each click.

24. Faces and Gazes Identifying faces Identifying gaze direction
Prosopagnosia
Fusiform face area
Evolution-based specific face mechanism?
Identifying gaze direction
Identification of direction of gaze may be automatic
Looking in that direction is voluntary

25. On the next slide, locate the red T
Selective Attention
On the next slide, locate the red T

26. T T T T T T T T

27. On the next slide, locate the red T
Selective Attention
On the next slide, locate the red T
(Again)

28. T L T L T L T L
T T L T T L T T
L T L T L T T L
T L T L T T L L
T T L T L T T T
L T T L T T T L

29. On the next slide, name the colors of the ink as quickly as possible
Divided Attention 1
On the next slide, name the colors of the ink as quickly as possible

30. XXXXX
XXXXX
XXXXX

31. On the next slide, name the colors of the ink as quickly as possible
Divided Attention 2
On the next slide, name the colors of the ink as quickly as possible

32. BLUE
PINK
RED
BLACK
GREEN
GREEN
BLUE
BLACK
PINK
RED
RED
BLACK
PINK
GREEN
BLUE

33. On the next slide, name the colors of the ink as quickly as possible
Divided Attention 3
On the next slide, name the colors of the ink as quickly as possible

34. RED
GREEN
BLACK
BLUE
PINK
BLUE
RED
GREEN
BLACK
PINK
GREEN
BLUE
RED
BLACK

35. Seeing Without Awareness
Blindsight
Change blindness
Repetition blindness
Attentional blink
Subliminal perception

36. Hearing
Sound waves
Pitch
Loudness
Decibel

37. Structures of the Ear Eardrum Hammer Anvil Stirrup Cochlea
Basilar membrane
Hair cells

38. Auditory Processing Hair cells Frequency theory Place theory
Tonotopic organization

39. Deafness Nerve deafness Tinnitus Conduction deafness
Hair cells destroyed by loud sounds
Tinnitus
Constant ringing
Conduction deafness

40. Organizing the Auditory World
Speech segmentation problem
Categorical perception
Locating sounds: two ears
Difference in phase
Difference in loudness
Onset difference
Locating sounds: one ear

41. Auditory Recognition and Identification
Phonemic restoration effect
Cocktail party phenomenon
Dichotic listening
Music
Absolute pitch

42. The Olfactory System Chemical senses Olfactory bulb Receptors
Lock and key
Pheromones
Synchronized menstrual cycles

43. Taste
Taste buds
Sweet, sour, salty, bitter
Smell affects taste

44. Somasthetic Senses Kinesthetic sense Vestibular sense Touch
Temperature
Pain

45. Other Senses? Magnetic sense Extrasensory perception (ESP)
Telepathy, clairvoyance
Problems
Failure to replicate
Lack of brain mechanism
Lack of signals
Alternative explanations