Sensation and Perception
Sensation: your window to the world Perception: interpreting what comes
in your window.
Just the basics…• Bottom-up processing• Top-down processing• Thresholds– JND
• Signal detection• Subliminal
Subliminal stimulation
ABSOLUTE THRESHOLD
Signal detection theorySensory experience
Your clothes are touching your skin.
Sensory Adaptation• Decreased
responsiveness to stimuli due to constant stimulation.
Vision• Our most
dominating sense.
Transduction• Order is Rods/Cones
to Bipolar to Ganglion to Optic Nerve.
• Sends info to thalamus- area called lateral geniculate nucleus (LGN).
• Then sent to cerebral cortexes.
• Where the optic nerves cross is called the optic chiasm.
In the Brain• Goes to the
Visual Cortex located in the Occipital Lobe of the Cerebral Cortex.
• Feature Detectors.
• Parallel Processing
We have specific cells that see the lines, motion, curves and other features of this turkey. These cells are called feature detectors.
Rods vs. Cones
• http://faculty.washington.edu/chudler/retina.html
• http://science.howstuffworks.com/environmental/life/human-biology/eye2.htm
Color Vision
Two Major Theories
Trichromatic TheoryThree types of cones:• Red• Blue• Green• These three types of
cones can make millions of combinations of colors.
• Does not explain afterimages or color blindness well.
Opponent-Process theory
The sensory receptors come in pairs.
• Red/Green• Yellow/Blue• Black/White• If one color is
stimulated, the other is inhibited.
Afterimages
Hearing
Our auditory sense
The Ear
• How we hear• Baby with cochlear implants• Cochlear implants
Touch• Mechanoreceptors
located in our skin.• Pressure, warmth, cold,
pain
Pain• Sensory vs. affective• Controlling pain– Endorphins– Gate control theory– Placebo control– Distraction
• Phantom limb• Social influences
Taste• Tongue– Papillae
• Taste buds– Taste cells
» Receptor sites• Sweet, salty,
sour, and bitter.• Flavor = taste +
olfaction
Vestibular Sense• Tells us where
our body is oriented in space.
• Our sense of balance.
• Located in our semicircular canals in our ears.
Kinesthetic Sense• Tells us where
our body parts are.
• Receptors located in our muscles and joints.
Olfactory• Chemistry– Individual signature
• Learned associations
Perception
GESTALT• a structure, configuration, or pattern
of physical, biological, or psychological phenomena so integrated as to constitute a functional unit with properties not derivable by summation of its parts
Law of Good Continuation
Law of Common Fate
Figure Ground Relationship
Our first perceptual decision is what is the image is the figure and what is the background.
Constancy• Objects change in
our eyes constantly as we or they move….but we are able to maintain content perception
• Shape Constancy• Size Constancy• Brightness
Constancy
Perceived Motion• Stroboscopic
effect (flip book effect)
• Phi phenomenon
Depth Perception• Monocular cues– Linear Perspective– Interposition– Relative size– Texture gradient– Shadowing
• Binocular cues– Retinal disparity– Convergence
Depth Perception
• Visual cliff experiment• 3D movies – retinal disparity
Variations in PerceptionInborn organizations + Learned
Variations• Adaptation• Perception set
(priming/predisposition)• Context• Emotion• Motivation
Human Factor Psychologists• AFFORDANCE– “It’s not your fault you turned on the
wrong burner…”