Download Psychology 101 Sensation vs Perception Sensation vs Perception

Sensation vs Perception
• What’
What’s the difference?
Psychology 101
Sensation
Sensation vs Perception
• Sensation
– What comes into our body through our
sensory organs
How do we construct our
environment?
• We construct it
• Our systems can be tricked!
• Perception
– What our brain does with that information
MullerMuller-Lyer
Titchener’
Titchener’s circles
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Red spirals
Look at the greys
Kanisza’
Kanisza’s triangle
An introduction to the Gestalt principles
How can we study our senses?
• What can we do to understand how visual
information is processed?
– Sounds?
– Smells?
• How could we study this in psychology?
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Psychophysics
Psychophysics: The point
• The main idea
• We notice some incoming information and
• To learn about our senses by pushing
don’
don’t process others
• Absolute thresholds
• Example: the auditory system
– Minimum threshold to detect something 50%
of the time
Signal Detection Theory
them to the limits
– Play a sound very quietly
– Eventually it’
it’ll be so quiet, you may not be
able to hear it
– Absolute threshold: the loudness that people
say they can hear the sound 50% of the time
Other things: Subliminal
Stimulation
• Stimulating our
consciousness
• Priming studies
– Changing opinions by
showing something
subliminally
– Ch_ _ _
Just Noticeable Difference
Just Noticeable Difference
• Weber’
Weber’s law
– Difference thresholds are
not constant, but
proportional
– Start with a 1lb book
• May notice a .1 lb change
– Now start with a 1000 lb
desk
• Will you notice a .1 lb
change?
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Sensory adaptation
What about vision?
• Do you feel your clothes if they are still?
• How about hearing a sound that hums in
• What about a line that is in one place in
the background consistently?
Two ways to processing the world
• BottomBottom-up processing:
– Our sensory systems experience the world
and send the information upwards to the
brain
• Eg.
Eg. watching a movie
your field of vision?
– Why is this different?
– Eyes are constantly moving
• Saccades
Vision: The beginning
• What do we see?
– Light is waves
• TopTop-down processing
– How our minds interpret what our senses
detect (ie
(ie.. seeing, hearing)
• Eg.
Eg. Don’
Don’t look behind the door
The visual spectrum
Vision
• We can only see a small portion of the
• The Eyeball
• Light shines through
waves of visual light
the cornea
• Becomes inverted on
the retina
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Parts of the eyeball
The Retina: The most important
part
• Cornea: outermost part
• Contains rods and cones
• Rods: nighttime use
– Protects the eye
• Pupil and Iris
– Allow light to enter
• Lens
– Focus light on retina
• Retina
– Back of eyeball where light is processed
Rods and Cones
– insensitive to color
– located in retinal periphery
– When you step into a movie theatre, it takes a while
to see because your rods are kicking in.
• Cones: 3 types of light sensitivity (red, green,
blue)
– essential for color perception
– daytime use
– primarily in center of retina
• better acuity
What do rods and cones do?
• They are sensitive to different
wavelengths
• Transduction
– Turns light into something our nervous
system can use
• Electrical signal
– Rods and Cones do this specifically for their
type (color) of light
What about problems seeing?
How the visual system works
• Nearsightedness: image focused too soon
• Farsightedness: image focused too far
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Stages to visual processing
Color vision
• Visual perception occurs in stages
• One are may process color
• Another may process depth or form
• YoungYoung-Helmholtz theory
– Trichromacy
– Found in the retina
• Opponent process theory
– RedRed-green, blueblue-yellow, and blackblack-white
– Input from one color inhibits the other color
YoungYoung-Helmholtz Theory
Opponent Process Theory
Hearing
• Sounds are waves
• Amplitude / Height = loudness
• Frequency = pitch
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The Ear
Typical Sounds
• Outer ear
– Ends at ear drum
• Middle ear
– Composed of bones
• Inner ear
– Cochlea
– Fluid filled
– Hairs
• Transduction
How we hear
Getting to the Brain
• Sound waves get to
• Different parts of the auditory cortex
•
•
•
the cochlea
Ripples in fluid
Hair cells sway with
the ripples
Different frequencies
of sound move the
hair cells that are in
different parts of the
cochlea
process the different frequencies of sound
Higher frequencies
processed in the
yellow region
Lower frequencies
processed in the blue
region
Sound Location Processing
Touch processing
• How can we tell where a sound is coming
• Multiple somatosensory
from?
– Difference in loudness between the two ears
• Interaural Intensity Difference
– Difference in time of arrival for the sound
waves between the two ears
• Interaural Time Difference
subsystems
– Touch
• Pressure, vibration
• Temperature
• Pain
– Joint position
– Muscle stretch
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Organization in the Brain
Taste
Taste buds: sensory receptors
Taste Sensations
sweet
sour
salty
bitter
Sensory Interaction
the principle that one sense may influence another
as when the smell of food influences its taste
The Tongue
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