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SENSATION AND PERCEPTION
Sensation—the process of detecting a physical
stimulus
Perception—the process of integrating,
organizing and interpreting sensations
Five Sensations:
vision
audition
olfaction
Is there a sixth??
gustation
touch
n
Anatomical substrate for vision, i.e., the pathway from
the stimulus in the environment to the occipital
lobe, where we “see”
Vision begins with a stimulus from the environment—
the range of the electromagnetic field from radio
waves to cosmic rays; only a small portion is visible
to humans
s
The pathway begins with
-light from the environment which then
passes through the
-cornea, pupil and lens
-light is focused on the retina
It is here that “transduction” occurs
*TRANSDUCTION* is the point at which the
stimulus from the environment (light)
becomes a nerve impulse (electrochemical
neurotransmission)
The photoreceptors in the lining of the retina
are called rods and cones
-axons of rods and cones form optic nerve
-optic nerve crosses at the optic chiasm
-nerves project to the lateral geniculate
nucleus of the thalamus to the
-visual cortex in the occipital lobe
WHERE WE SEE!
Hearing begins in the environment and ends in
the auditory cortex in the temporal lobe
PATHWAY
The stimulus from the environment is sound, in
the form of waves.
The sound is “funnelled” by the outer ear—
pinna, ear canal and eardrum.
Middle ear—three tiny bones, called ossicles–
anvil, stirrup, hammer
Inner ear—cochlea
snail-shaped structure about the size of a pea
lined with hair cells that bend, causing
“transduction”
*TRANSDUCTION* is when a stimulus from the
environment (sound) becomes a neural
impulse (electrochemical neurotransmission)
Transduction occurs at basilar membranes
Axon neurons become the optic nerve
Optic nerve projects to the medial geniculate
nucleus of the thalamus
Thalamus to auditory cortex in
Temporal lobe, where we “hear”.
If a tree falls in the forest, and there’s no one there
to hear it, does it make a sound?
OTHER SENSATIONS
• Smell
• Taste
• Touch
Also—kinesthesia (body movement)
and vestibular (balance)
PERCEPTION
• refers to the process of integrating, organizing
and interpreting sensory information into
meaningful representations
GESTALT LAWS OF
FORM PERCEPTION
• Figure-ground
• The Law of Similarity
• Law of Closure
• Law of Good Continuation
• Law of Proximity
• Law of Simplicity
Depth Perception
ILLUSIONS
(MISPERCEPTIONS)
Muller-Lyer
• Moon Illusion
Shepherd Table’s Illusion