The document discusses the visual system and visual perception as well as other sensory systems. It describes how vision works through the eye's ability to accommodate focus, the role of the retina's rods and cones in detecting light and color, and how visual information is transmitted through the optic nerve. It also explains several principles of visual perception like constancy and Gestalt laws of grouping. The document further examines audition, gustation, olfaction, touch, and pain as well as the structures and processes involved in these other sensory systems.

1. Sensation & Perception
➔ The Visual System
➔ Visual Perception
➔ Other Sensory Systems

2. 2
Sensation & Perception

6. 6
• SENSATION: activation of the sensory organs by physical
stimulation
• TRANSDUCTION: physical energy is changed into neural
impulses and sent to the brain
• PERCEPTION: organizing & interpreting sensory info,
transforming it into meaningful objects and events

7. VISION
7

8. 8
VISION

9. • Hold the image like this:
• Cover your left eye with your hand.
• Focus your right eye on the cross.
• Move the piece of paper backwards and forwards
until the dot disappears.
Blind Spot Demonstration!

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ACCOMMODATION:
changing the shape of
the lens to bend light
rays

11. VISION

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CELLS IN THE RETINA

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TRANSDUCTION:
1. Light hits the
photoreceptors
2. Message transmitted
to the bipolar cell
3. Message transmitted
to the ganglion cell
4. Message is sent to
the brain
Ganglion Cell
Bipolar Cell
Photoreceptor
Back of the eye
Light

15. PHOTORECEPTORS
15
RODS
•120 million per eye
•Low light
•No color detection
•Peripheral
CONES
•7 million per eye
•Bright Light
•Detect color
•Visual acuity
•Central

16. 16

17. Diagram of the neural pathway from
the eyes to the corresponding regions
in the brain to perceive sensory input

19. Diagram depicting the primary sensory
areas of the human brain

20. COLOR VISION
• TRICHROMATIC THEORY:
– Three types of cones (S, M, L)
– Sensitive to different wavelengths of light

21. COLOR VISION

22. COLOR VISION
• OPPONENT-PROCESS THEORY:
– Some cells respond to opposing pairs of colors
– Excited by one color in the pair but inhibited the
other color

23. COLOR VISION

24. Sensation & Perception
➔ The Visual System
➔ Visual Perception
➔ Other Sensory Systems

25. 25
GESTALT PRINCIPLES OF ORGANIZATION
The whole is greater than the sum of its parts.
– Whole = perceptions
– Parts = sensations
Three Basic Observations
1. We do not always perceive the truth.
2. Perceptions are organized .
3. Perceptions are contextualized.

26. 1. WE DO NOT ALWAYS PERCEIVE THE
TRUTH.

27. Undokai Illusion Zollner Illusion

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2. PERCEPTIONS ARE ORGANIZED

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3. PERCEPTIONS ARE CONTEXTUALIZED.

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SIZE CONSTANCY: the perceived size of an object
remains the same even though the size of its
retinal image changes

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SHAPE CONSTANCY: if an object rotates, you still
perceive it as maintaining the same shape

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SHAPE CONSTANCY: if an object rotates, you still
perceive it as maintaining the same shape

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COLOR CONSTANCY: we perceive objects as having
consistent covers even when reflecting different
wavelengths of light

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COUNT THE BLACK CIRCLES

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GESTALT LAWS OF GROUPING
1. SIMPLICITY: we group things to give us the
simplest interpretation
Law of Pragnanz

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GESTALT LAWS OF GROUPING
2. PROXIMITY: things that are close together
seem to go together.

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GESTALT LAWS OF GROUPING
3. SIMILARITY: we group like shapes together.

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GESTALT LAWS OF GROUPING
4. GOOD CONTINUATION: we view things as
forming continuous patterns

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GESTALT LAWS OF GROUPING
5. CLOSURE: when presented with something
incomplete, your brain makes it complete

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Our perception
depends on what
we are looking for.

42. Our
perception
depends
on what we
are looking
for.

43. 43
Our perception
depends on
what we are
looking for.

44. Sensation & Perception
➔ The Visual System
➔ Visual Perception
➔ Other Sensory Systems

45. AUDITION

46. HOW THE EAR WORKS
THE OUTER EAR
• PINNA: the external
part of the ear, collects
and funnels sound into
the ear canal
• TYMPANIC
MEMBRANE: vibrates in
response to sound
waves

47. TYMPANIC MEMBRANE

48. HOW THE EAR WORKS
THE MIDDLE EAR
• OSSICLES: tiny bones that vibrate in reaction to sound
waves from the auditory canal
• OVAL WINDOW: a membrane which covers
the inner ear

49. HOW THE EAR WORKS
THE INNER EAR
COCHLEA: inner-ear
structure; contains
the receptor cells for
hearing
HAIR CELLS: receptor
cells for hearing, line
the basilar membrane

52. PITCH PERCEPTION
• TEMPORAL CODING: the firing rates hair cells
match the frequency of the sound wave
– Low frequency sounds
• PLACE CODING: the frequency of the sound
wave activates hair cells at different locations
in the cochlea
– High frequency sounds

53. Diagram of an unrolled cochlea and
the different regions that handle
different frequencies

54. GUSTATION

55. GUSTATION

56. GUSTATION

57. OLFACTION

58. OLFACTION

59. TOUCH & PAIN

60. TOUCH & PAIN

61. TOUCH & PAIN
• GATE CONTROL THEORY
– Pain opens a neural “gate” opens allowing pain signals
to be carried to the brain
– Larger sensory nerve fibers can fire and close the gate,
preventing pain perception

62. TOUCH & PAIN
• Closing the pain gate:
– Drug treatments (ibuprofen, acetaminophen,
Novocain, anesthetics)
– Cognitive states (distraction, positive mood,
relaxation) can close the pain gate.
• Opening the pain gate:
– Worry about the pain
– Focusing on the painful stimulus