Sensation and Perception

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Sensation and Perception

• Sensation Stimulus of sense organ
• Perception Cognitive process
• What makes a stimulus detectable
• Absolute threshold Can detect 50 of time
• Just noticeable difference Smallest difference
  in amount.

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Signal Detection Theory

• Involves decision making process
• USS Stark vs. USS Vincennes

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Sensory Adaptation

• Gradual sensory decline due to prolonged exposure
• Ex. Clothes
• Keeps focus on novel stimuli

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Light

• Amplitude (brightness)
• Wavelength (color)
• Eye

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Accommodation

• Adjustment of lens to alter visual focus
• Lens Problems
• Nearsightedness
• Farsightedness
• Astigmatism
• Cataract ?
• Glaucoma

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Retina

• Rods (125 million)
• Cones (6.4 million)
• Optic Disc Blind spot page 203
• Info through bipolar and ganglion cells to optic
  nerve and thalamus

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Color vision

• Trichromatic theory
• Opponent Process Theory

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Perceptual Set

• Biological predisposition to perceive stimuli in
  certain way
• Helps make sense of stimuli quickly
• Bottom-up processing Look at parts and assume
  whole
• Top-down processing processing of whole by
  filling in missing parts

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Figure/Ground

• Deciding what is primary figure sets stage for
  perception

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More Figure/Ground
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Proximity

• Close objects grouped together
• Describe what you see

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Similarity

• Similar objects grouped together

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Continuity

• Perceive continuous patterns when available

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Closure

• Top-down processing

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These can result in misperception

• Ex you brain tries to use similarity to group
  the black and white cubes

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Attempting Continuity and Closure at same time
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Figure/Ground Fun
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More fun
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Cues for 3D
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More 3D Cues
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More Fun
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Continuity
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Moving gears

• http//www.flickr.com/photos/minorityofone/1435102
  3/in/pool-780403_at_N21

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Moving?
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Afterimage

• http//www.flickr.com/photos/28118406_at_N08/26151701
  93/sizes/o/in/pool-780403_at_N21/

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Hearing

• Frequency 20-20000 Hz.
• Decibels
• 0 Silence
• 30 Whisper
• 60 Normal Conversation
• 120 Metallica
• 140 Jet Engine
• 200 Rocket engine

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Ear

• Pinna
• Ear Drum
• Ossicles Hammer Anvil Stirrup
• Cochlea
• Basilar Membrane
• Semicircular canals

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Taste

• Tastebuds are not neurons
• Four Primary Tastes and why they exist
• Sugar
• Salt
• Sour
• Bitter
• Secondary tastes
• Metallic
• Glutamate
• Perception of Flavor

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Touch

• Arguably best human sense
• Loss of fur
• Pressure
• Hot/Cold
• Slow/Fast Pain pathways
• Situation perception of pain