Transcript Psychological Research Methods

Sensation & Perception
Vision and Hearing
• Goals  Identify the structures of the eye and
explain their function in vision; compare the
different theories of vision.
Vision: Electromagnetic Spectrum
(ROY G BIV)
The Eye
 Accommodation- lens changes shape to
focus object on the retina (adjusts if
object is nearer or more distant)
 Nearsightedness Nearby objects = clearer
 Distant objects = poor, focused in front of retina
 Farsightedness Distant objects = clearer
 Nearby objects = poor, focused behind retina
Farsighted
Vision
Nearsighted
Vision
Normal
Vision
Vision - Photoreceptors
Pathways from the Eyes to the Visual
Cortex
Vision- Physical Properties of
Waves
Short wavelength=high frequency
(bluish colors, high-pitched sounds)
Great amplitude
(bright colors, loud sounds)
Long wavelength=low frequency
(reddish colors, low-pitched sounds)
Small amplitude
(dull colors, soft sounds)
Color Vision
• Young Helmholtz Trichromatic (ThreeColor) Theory
– Three different cones (color receptors)
• Red
• Blue
• Green
Color Vision
Opponent-Process Theory- opposing retinal
processes enable color vision (cones alternate
between colors)
“ON”
“OFF”
red
green
green
red
blue
yellow
yellow
blue
black
white
white
black
After Images
• Stare at the eye of the red parrot while you slowly count to 20, then
immediately look at one spot in the empty birdcage. The faint, ghostly
image of a blue-green bird should appear in the cage.
Colorblindness
• Monochromats – colorblind
• Dichromats – partially colorblind
• Trichromats – normal color vision
THE EAR
• Auditory Canal: funnel-shaped opening
from outer ear to eardrum
• Eardrum: thin membrane, separates
outer/middle ear, vibrates for sound waves
• Ossicles: tiny bones in middle ear that
amplify sound waves & transmit to cochlea
– Hammer (malleus), anvil (incus), stirrup
(stapes)
• Oval window: between middle and inner
ear, passes vibrations to cochlea
• Semi-circular canals
• Cochlea: coiled, fluid-filled tube where
sound is made into a neural impulse
– Hair cells: in cochlea, bend due to vibrations,
therefore making neural message
• Auditory nerve:
transmits
sound message
to brain
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.
• Sound localization: ability to identify
location of a sound
Place Theory
High
frequencies
(high pitch)
• 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.
Low
frequencies
(low pitch)
Frequency Theory
• All the hairs
vibrate but at
different speeds.
• Volley principle:
neurons alternate
firing (accounts for
high
frequency/high
pitches)
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.