1. Sensation and perception
chapter5

2. Journal topic:
If you had to loose one of your five senses, which would you choose to live without? Vision Hearing Taste Touch Smell

3. For the following Pictures:
Note which image you prefer and why? Be specific! Don’t just say because it looks better

9. Why? Next: You will be in five groups
Why did you choose the pictures you did?
What senses did you use to help make your decision?
How did your senses impact our perception of the world?!
Next:
You will be in five groups
You will take on the role of one of the senses
You must come up with a unique way to present your sense to the class. You can create a poster, rap, skit, poem
Use your books to find information on location on the body, cell receptors, receptor nerves… quality information on your sense
You have 25 minutes

11. Definitions
Sensation- electrical activity in the brain created by colors, forms, sounds, smells, tastes, and so on
The detection of physical energy emitted or reflected by physical objects.
It occurs when energy in the external environment or the body stimulates receptors in the sense organs.
Perception-
The process by which the brain organizes and interprets sensory information.

12. The Riddle of Separate Sensations
Sensation & Perception
12/1/2018
The Riddle of Separate Sensations
Sense receptors
Specialized cells that convert physical energy in the environment or the body to electrical energy that can be transmitted as nerve impulses to the brain.
©1999 Prentice Hall

13. Specialized cells that respond to a particular type of energy
The Basic Process
Receptor cells….
Specialized cells that respond to a particular type of energy
How these cells work:
applying pressure with your finger to your eye results in a visual experience
These receptor cells will communicate with the neurons to let your brain know what's what
There is a receptor cell for each sense…
transparent protective coating over the front of the eye

14. Sensation & Perception Processes
12/1/2018
Sensation & Perception Processes
Figure 3.Davis 2 from:
Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.
©1999 Prentice Hall

15. Measuring The Senses: Threshold
Threshold- a dividing line between what has detectable energy and what does not
Ex- motion light sensors
Absolute- the minimal amount of physical energy required to produce a sensation/cause detection
-produces a response 50% of the time (a feather floats by motion light and light is on)
The minimum amount of energy that can be detected 50% of the time
Difference- the smallest amount of change needed to stimulate senses
The smallest difference in stimulation that can be reliably detected by an observer when two stimuli are compared;
Also called Just Noticeable Difference (JND).
The smallest change in stimulation that can be detected 50% of the time
Signal-detection theory-
A psychophysical theory that divides the detection of a sensory signal into a sensory process and a decision process.

16. Absolute Sensory Thresholds
Sensation & Perception
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Absolute Sensory Thresholds
Vision:
A single candle flame from 30 miles on a dark, clear night
Hearing:
The tick of a watch from 20 feet in total quiet
Smell:
1 drop of perfume in a 6-room apartment
Touch:
The wing of a bee on your cheek, dropped from 1 cm
Taste:
1 tsp. Sugar in 2 gal. water
©1999 Prentice Hall

17. Sensory Adaptation and Deprivation
Sensation & Perception
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Sensory Adaptation and Deprivation
Adaptation
The reduction or disappearance of sensory responsiveness when stimulation is unchanging or repetitious.
Prevents us from having to continuously respond to unimportant information.
Deprivation
The absence of normal levels of sensory stimulation.
©1999 Prentice Hall

18. Quick test: What color is my hair!!!!
Quick Quiz
This may take awhile…..
Quick test: What color is my hair!!!!
What color is my Shirt, and isnt it cute too?
So how do you know that those color are right?

19. Sensation & Perception
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An Eye on the World
Cornea
Protects eye and bends light toward lens.
Lens
Focuses on objects by changing shape.
Iris
Controls amount of light that gets into eye.
Pupil
Widens or dilates to let in more light.
©1999 Prentice Hall

20. Cells in the retina that are sensitive to light
Receptor Cells
Cells in the retina that are sensitive to light
Visual receptors are called rods and cones

21. Sensation & Perception
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An Eye on the World
Retina
Neural tissue lining the back of the eyeball’s interior, which contains the receptors for vision.
Rods
Visual receptors that respond to dim light.
Cones
Visual receptors involved in colour vision. Most humans have 3 types of cones.
©1999 Prentice Hall

22. Sensation & Perception
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Vision: What We See
Hue
Visual experience specified by colour names and related to the wavelength of light.
Brightness
Lightness and luminance; the visual experience related to the amount of light emitted from or reflected by an object.
Saturation
Vividness or purity of colour; the visual experience related to the complexity of light waves.
©1999 Prentice Hall

23. From Eye to Brain Optic nerve Optic chiasm
Made up of axons of ganglion cells
carries neural messages from each eye to brain
Optic chiasm
Point where part of each optic nerve crosses to the other side of the brain

24. Color Vision in Other Species
Other species see colors differently than humans
Most other mammals are dichromats
Rodents tend to be monochromats, as are owls who have only rods
Bees can see ultraviolet light

25. Why the Visual System is not a Camera
Sensation & Perception
12/1/2018
Why the Visual System is not a Camera
Much visual processing is done in the brain.
Some cortical cells respond to lines in specific orientations (e.g. horizontal).
Other cells in the cortex respond to other shapes (e.g., bulls-eyes, spirals, faces).
Feature-detectors
Cells in the visual cortex that are sensitive to specific features of the environment.
©1999 Prentice Hall

26. Sensation & Perception
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Ambiguous Figure
Colored surface can be either the outside front surface or the inside back surface
Cannot simultaneously be both
Brain can interpret the ambiguous cues two different ways
©1999 Prentice Hall

27. Opponent-Process Theory
Sensation & Perception
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Opponent-Process Theory
A competing theory of colour vision, which assumes that the visual system treats pairs of colours as opposing or antagonistic.
Opponent-Process cells are inhibited by a colour, and have a burst of activity when it is removed.
©1999 Prentice Hall

28. Sensation & Perception
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Afterimages
Figure 3.10 from:
Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.
©1999 Prentice Hall

30. Test of Colour Deficiency
Sensation & Perception
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Test of Colour Deficiency
Figure 3.12 from:
Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.
©1999 Prentice Hall

31. Sensation & Perception
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What We Hear
Loudness
The dimension of auditory experience related to the intensity of a pressure wave.
Pitch
The dimension of auditory experience related to the frequency of a pressure wave.
Timbre (pronounced “TAM-bur”)
The distinguishing quality of sound; the dimension of auditory experience related to the complexity of the pressure wave.
©1999 Prentice Hall

32. The Ear Basilar membrane Auditory nerve
Membrane in the cochlea which contains receptor cells, called hair cells
Auditory nerve
Connection from ear to brain
Provides information to both sides of brain

33. Sensation & Perception
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An Ear on the World
©1999 Prentice Hall

34. Auditory Localization
Sensation & Perception
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Auditory Localization
Sounds from different directions are not identical as they arrive at left and right ears
Loudness
Timing
Phase
The brain calculates a sound’s location by using these differences.
Figure 3.14 from:
Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.
©1999 Prentice Hall

35. Pause!
We have briefly seen the 5 senses WE have looked in-depth at vision and hearing Based on what you already know, which of the five senses are the most active? What are the cell receptors called for vision and hearing? Going back to our discussion, How do our senses impact our perceptions? Bring in a blindfold for tomorrow…

36. Taste: Savoury Sensations
Sensation & Perception
12/1/2018
Taste: Savoury Sensations
Papillae
Knoblike elevations on the tongue, containing the taste buds (Singular: papilla).
Taste buds
Nests of taste-receptor cells.
©1999 Prentice Hall

37. Sensation & Perception
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Taste Buds
Photograph of tongue surface (top), magnified 75 times.
10,000 taste buds line the tongue and mouth.
Taste receptors are down inside the “bud”
Children have more taste buds than adults.
Figure 3.17 from:
Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.
©1999 Prentice Hall

38. Sensation & Perception
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Four Tastes
Four basic tastes
Salty, sour, bitter and sweet.
Different people have different tastes based on:
Genetics
Culture
Learning
Food attractiveness
©1999 Prentice Hall

39. Smell: The Sense of Scents
Sensation & Perception
12/1/2018
Smell: The Sense of Scents
Airborne chemical molecules enter the nose and circulate through the nasal cavity.
Vapors can also enter through the mouth and pass into nasal cavity.
Receptors on the roof of the nasal cavity detect these molecules.
©1999 Prentice Hall

40. Sensation & Perception
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Olfactory System
Figure 3.16 from:
Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.
©1999 Prentice Hall

41. Sensation & Perception
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Sensitivity to Touch
Figure 3.18 from:
Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.
©1999 Prentice Hall

42. Gate-Control Theory of Pain
Sensation & Perception
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Gate-Control Theory of Pain
Experience of pain depends (in part) on whether the pain impulse gets past neurological “gate” in the spinal cord and thus reaches the brain.
©1999 Prentice Hall

43. Sensation & Perception
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Form Perception
Gestalt principles describe the brain’s organization of sensory building blocks into meaningful units and patterns.
©1999 Prentice Hall

44. Sensation & Perception
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Figure and Ground
Proximity
Seeing 3 pair of lines in A.
Similarity
Seeing columns of orange and red dots in B.
Continuity
Seeing lines that connect 1 to 2 and 3 to 4 in C.
Closure
Seeing a horse in D.
Figure 3.23 from:
Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.
©1999 Prentice Hall

45. Depth and Distance Perception
Sensation & Perception
12/1/2018
Depth and Distance Perception
Binocular Cues:
Visual cues to depth or distance that require the use of both eyes.
Convergence: Turning inward of the eyes, which occurs when they focus on a nearby object.
Retinal Disparity: The slight difference in lateral separation between two objects as seen by the left eye and the right eye.
©1999 Prentice Hall

46. Depth and Distance Perception
Sensation & Perception
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Depth and Distance Perception
Visual cues to depth or distance that can be used by one eye alone.
©1999 Prentice Hall

47. Sensation & Perception
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The Ames Room
A specially-built room that makes people seem to change size as they move around in it
The room is not a rectangle, as viewers assume it is
A single peephole prevents using binocular depth cues
Figure 3.24 from:
Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.
©1999 Prentice Hall

48. Sensation & Perception
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Visual Constancies
The accurate perception of objects as stable or unchanged despite changes in the sensory patterns they produce.
Shape constancy
Location constancy
Size constancy
Brightness constancy
Colour constancy
©1999 Prentice Hall

49. Sensation & Perception
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Shape Constancy
Even though these images cast shadows of different shapes, we still see the quarter as round
Figure 3.25 from:
Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.
©1999 Prentice Hall

50. Sensation & Perception
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Visual Illusions
Illusions are valuable in understanding perception because they are systematic errors.
Illusions provide hints about perceptual strategies.
In the Muller-Lyer illusion (above) we tend to perceive the line on the right as slightly longer than the one on the left.
Figure 5.07 from
Wade, C., & Tavris, C. (2002). Invitation to Psychology, 2nd Ed. Upper Saddle River, NJ: Prentice Hall.
©1999 Prentice Hall

51. Sensation & Perception
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The Ponzo Illusion
Linear perspective provides context
Side lines seem to converge
Top line seems farther away
But the retinal images of the red lines are equal!
Figure 3.3Davis 2 from:
Kassin, S. (1998). Psychology, second edition. Upper Saddle River, NJ: Prentice Hall.
©1999 Prentice Hall

52. Sensation & Perception
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Fooling the Eye
The cats in (a) are the same size
The diagonal lines in (b) are parallel
You can create a “floating fingertip frankfurter” by holding hands as shown, 5-10” in front of face.
©1999 Prentice Hall

53. The Environment Within
Sensation & Perception
12/1/2018
The Environment Within
Kinesthesis
The sense of body position and movement of body parts; also called kinesthesia.
Equilibrium
The sense of balance.
Semicircular Canals
Sense organs in the inner ear, which contribute to equilibrium by responding to rotation of the head.
©1999 Prentice Hall