Download Sensation2011

Sensation and Perception
Sensation: your window to the world
Perception: interpreting what comes
in your window.
Sensation
• The process by which our
sensory receptors and nervous
system receive stimulus from the
environment.
Perception
• The process of organizing and
interpreting sensory information,
enabling us to recognize
meaningful objects and events.
Transduction
• Transforming signals
into neural impulses.
• Information goes
from the senses to
the thalamus , then
to the various areas
in the brain.
Remember Ethan in Sky High. He
changes his body to slime. Solid
form to liquid form. Change from
one form of energy to another.
Transduction
Receptors –
Specialized neurons that are activated by
stimulation and transduce (convert) it into a
nerve impulse
Sensory pathway –
Bundles of neurons that carry information from
the sense organs to the brain
What if we could sense everything?
Life would hurt.
So we can only take in a window of what is out
there.
This is the study of psychophysics: relationship
between physical stimuli and our psychological
experiences to them.
Sensory Adaptation
• Decreased
responsiveness to
stimuli due to
constant stimulation.
Do you feel your underwear all day?
Cocktail-party phenomenon
• The cocktail party effect
describes the ability to
focus one's listening
attention on a single talker
among a mixture of
conversations and
background noises, ignoring
other conversations.
• Form of selective attention.
Absolute Threshold
• The minimum stimulation needed to
detect a stimulus 50% of the time.
Absolute Threshold
Demonstration
Difference Threshold
• The minimum difference that a person
can detect between two stimuli.
• Also known as Just Noticeable
Difference
Can you tell the difference?
Weber’s Law
• The idea that, to perceive a difference
between two stimuli, they must differ
by a constant percentage; not a
constant amount.
Signal Detection Theory
• Predicts how we detect a stimulus amid
other stimuli.
• Assumes that we do not have an absolute
threshold.
• We detect stuff based on our experiences,
motivations and fatigue level.
Signal Detection Theory
Subliminal Persuasion
Studies have found that subliminal words
flashed briefly on a screen can “prime” a
person’s later responses
No controlled research has ever shown
that subliminal messages delivered to a
mass audience can influence people’s
buying habits
WHY?
Copyright © Allyn and Bacon 2006
Vision
• Our most dominating
sense.
• Visual Capture
Phase One: Gathering Light
•
•
•
•
•
The height of a wave gives us it’s intensity (brightness).
The length of the wave gives us it’s hue (color).
ROY G BIV
The longer the wave the more red.
The shorter the wavelength the more violet.
Phase Two: Getting the light in
the eye
Phase Three: Transduction
Transduction Continued
• Order is Rods/Cones to
Bipolar to Ganglion to
Optic Nerve.
• Sends info to thalamusarea called lateral
geniculate nucleus
(LGN).
• Then sent to cerebral
cortexes.
• Where the optic nerves
cross is called the optic
chiasm.
Phase Four: In the Brain
We have specific cells that see
the lines, motion, curves and
other features of this turkey.
These cells are called feature
detectors.
• Goes to the Visual
Cortex located in
the Occipital Lobe
of the Cerebral
Cortex.
• Feature Detectors.
• Parallel Processing
Color Vision
Two Major Theories
Trichromatic Theory
Three 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
We hear sound WAVES
• The height of the wave gives us the amplitude of the
sound.
• The frequency of the wave gives us the pitch if the sound.
The Ear
Transduction in the ear
• Sound waves hit the eardrum
then anvil then hammer then
stirrup then oval window.
• Everything is just vibrating.
• Then the cochlea vibrates.
• The cochlea is lined with mucus
called basilar membrane.
• In basilar membrane there are
hair cells.
• When hair cells vibrate they
turn vibrations into neural
impulses which are called organ
of Corti.
• Sent then to thalamus up
auditory nerve.
It is all about the vibrations!!!
Pitch Theories
Place Theory and Frequency Theory
Place Theory
• Different hairs
vibrate in the
cochlea when they
different pitches.
• So some hairs
vibrate when they
hear high and other
vibrate when they
hear low pitches.
Frequency Theory
• All the hairs vibrate
but at different
speeds.
Deafness
Conduction Deafness
• Something goes wrong
with the sound and the
vibration on the way to
the cochlea.
• You can replace the
bones or get a hearing
aid to help.
Nerve (sensorineural)
Deafness
• The hair cells in the cochlea
get damaged.
• Loud noises can cause this
type of deafness.
• NO WAY to replace the hairs.
• Cochlea implant is possible.
Touch
• Receptors located in
our skin.
• Gate Control Theory
of Pain
Taste
• We have bumps on
our tongue called
papillae.
• Taste buds are
located on the
papillae (they are
actually all over the
mouth).
• Sweet, salty, sour
and bitter.
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.
Without the kinesthetic sense
you could touch the button to
make copies of your buttocks.