Transcript Introduction to Sensation and Perception

Sensation and
Perception
Myers: Ch. 4
Sensation
The process by which our
sensory receptors and
nervous system receive
stimulus from the
environment. (information
we get from our 5 senses)
Perception
• The process of organizing and
interpreting sensory information,
enabling us to recognize meaningful
objects and events
Top Down vs. bottom up
• Bottom-up processing
• Top-down processing
– a progression from
individual
elements to the whole
(start small then
work your way up) (start
focusing on trees,
then you pay attention to
the forest).
– start with the forest
and work your attention
down to the individual
tree.
I cdnuolt blveiee taht I cluod aulaclty
uesdnatnrd waht I was rdanieg. The
phaonmneal pweor of the hmuan mnid,
aoccdrnig to a rscheearch at Cmabrigde
Uinervtisy, it dseno't mtaetr in waht oerdr the
ltteres in a wrod are, the olny iproamtnt tihng is
taht the frsit and lsat ltteer be in the rghit pclae.
The rset can be a taotl mses and you can sitll
raed it whotuit a pboerlm. Tihs is bcuseae the
huamn mnid deos not raed ervey lteter by istlef,
but the wrod as a wlohe. Azanmig huh? yaeh
and I awlyas tghuhot slpeling was ipmorantt!
• Write down the word I show
your side of the classroom do
not share it with the other side.
• True or False: As long as our
eyes are open we are seeing.
Selective Attention
Selective Attention
Inattentional Blindness
• Can you count how many
passes?
• Cell Phones
• Deal or no Deal
Change Blindness
Absolute Thresholds:
The minimum stimulation needed to
detect a particular stimulus 50 percent of
the time.
http://www.freemosquitoringtones.org/
Difference
threshold
• ‘Just noticeable
difference’ JND
• Weber’s Law: principle
that in order to be
perceived as different,
two stimuli must differ
by a constant
percentage
• Salary example
Signal detection
theory
• Detection depends
on context.
• How many of you
feel picked on by
teachers?
Subliminal
Persuasion
• Stimulus below the
threshold
• political
campaigning (text p. 89)
• Priming
Write down what
you see.
Sensory adaptation
Raise your hand if you feel your
underwear right now.
Vision: TED Talk
• Color does
not really
exist.
Figure 4.8 The spectrum of electromagnetic energy This spectrum ranges from gamma rays as
short as the diameter of an atom to radio waves over a mile long. The narrow band of wavelengths
visible to the human eye (shown enlarged) extends from the shorter waves of blue-violet light to the
longer waves of red light.
© 2010 by Worth Publishers
Visible Light waves
Anatomy of the eye
Figure 4.10 The eye Light rays reflected from the candle pass through the cornea, pupil, and lens.
The curvature and thickness of the lens change to bring either nearby or distant objects into focus on
the retina. Rays from the top of the candle strike the bottom of the retina and those from the left side
of the candle strike the right side of the retina. The candle’s retinal image is thus upside-down and
reversed.
• I need a volunteer with no
significant disturbances in
vision.
Retina
Figure 4.11 The retina’s reaction to light
© 2010 by Worth Publishers
TRAnsduction
• Converting physical signals from the
environment into neural signals sent through
the nervous system.
• Visual transduction occurs in the retina
Ganglion Cells
Visual Process
cont…
Figure 4.13 Pathway from the eyes to the visual cortex Ganglion axons forming the optic nerve
run to the thalamus, where they synapse with neurons that run to the visual cortex.
© 2010 by Worth Publishers
Feature detectors
Figure 4.14 The telltale brain Looking at faces, houses, and chairs activates different brain areas in
this right-facing brain.
© 2010 by Worth Publishers
Parallel Processing
Figure 4.15 Parallel processing Studies of patients with brain damage suggest that the brain
delegates the work of processing color, motion, form, and depth to different areas. After taking a
scene apart, how does the brain integrate these subdimensions into the perceived image? The answer
to this question is the Holy Grail of vision research.
© 2010 by Worth Publishers
Movement
aftereffects
The visual Process:
beginning to end
Figure 4.16 A simplified summary of visual information processing
© 2010 by Worth Publishers
Figure 4.17 Color-deficient vision People who suffer red-green deficiency have trouble perceiving
the number within the design.
© 2010 by Worth Publishers
Color Vision
• Trichromatic Theory—Helmholtz
• Three types of receptors in the retina
• Red, Green, Blue
• Opponent-process theory
• Three pairs of receptors in the retina
• Red-green
• Blue-yellow
• Black-white
• Afterimage
• “On-Off” switch—we will never see bluish-yellow
Figure 4.18 Afterimage effect Stare at the center of the flag for a minute and then shift your eyes to
the dot in the white space beside it. What do you see? (After tiring your neural response to black,
green, and yellow, you should see their opponent colors.) Stare at a white wall and note how the size
of the flag grows with the projection distance!
© 2010 by Worth Publishers
Hearing
•Does your voice sound
high-pitched when you
hear a recording of it?
•Plug your ears and talk
in a normal voice
The Stimulus Input: Sound
Waves
• Frequency/wavelength
• Pitch
• Hertz (Hz)
• Amplitude
• Loudness
• Measured in
decibels
The structure of the ear
The ear is divided into the outer, middle
and inner ear.
The Ear
• Outer ear
• Auditory canal
• Ear drum
The Ear
• Middle ear
• Hammer, anvil, stirrup
The Ear
• Inner ear
• Oval window
• Cochlea
• Basilar membrane
• Auditory nerve
• Auditory cortex
The structure of the ear
Auditory nerve
• Auditory Transduction Animation
#1
Parts of the Ear
• Eardrum = tight membrane that vibrates when
struck by sound waves.
• Bones of the middle ear = the hammer, anvil,
stirrup which vibrate with the eardrum.
• Oval window = where the stirrup connects to the
cochlea.
• Cochlea = a coiled, bony, fluid-filled tube in the
inner ear through which sound waves trigger
nerve impulses.
• Auditory nerve = nerve which sends the auditory
message to the brain via the thalamus.
Neural impulse to the brain
The Ear
Perceiving Loudness
• Basilar membrane’s hair cells
• Animation
Cochlea and loud sounds
The Ear
Perceiving Pitch
• Place theory (animation)
• High pitched sounds
• Frequency theory
• Low pitched sounds
• Volley principle (sum of neural
firing sequence)
The Ear
Locating Sounds
• Stereophonic hearing
• Localization of sounds
• Intensity
• Speed of the sound
Hearing Loss
• 60% of US college students suffer
from hearing loss (U. of Tennessee)
• Informal hearing test—hold your
hand up like you’re taking an oath
and rub your fingers together
• Freehearingtest.com
Hearing Loss and Deaf Culture
• Hearing loss
• Conduction hearing loss
• Sensorineural hearing loss
• Cochlea implant
• Signing
• Deafness and diversity
• Cross-cultural language
Other Senses
Smell
• Olfaction
• Chemical sense
• Odor molecules
• Olfactory bulb
• Olfactory nerve
Smell (olfaction)
Smell cont…
• Anosmia—lack of
smell
• Does it impact your
memory?
• Dogs have 200 million
smell receptors
(however they can’t
distinguish between
identical twins)
• Humans have 10
million
Smell and age
Taste
• Sweet, sour, salty, bitter and
Umami
• Taste buds
• Chemical
sense
• Age and taste
supertasters
Taste
• Why does toothpaste make OJ
taste bad?
Touch
• Extremely important
• Baby monkey not allowed to
touch mothers experiences severe
unhappiness
Touch
• Types of touch
–Pressure
–Temperature
–Pain
Touch
• Kinesthesis—placement of body
• Stretch receptors
• Golgi tendon organs
• Ian Waterman (1972) Case
• Vestibular
– Placement of head
– Semicircular canals
– i.e., cats and whiskers
Touch
• Rubber hand illusion
Pain
• What would life be
like without pain?
• Biological Influences
• Nociceptors
• Gate-control theory
• Endorphines
Biopsychosocial approach to pain
The pain circuit
Advertisement
assignment:
• Watch TV
• What sensory cues are being
used to market that product?
Perceptual Organization
Gestalt— “Form or whole”
• Tendency to see the
big picture
• We filter in a way
that makes sense to
us
1) Form Perception
• A. Figure and
Ground
• ‘Main idea’ of
your senses
Form Perception cont…
• B. Grouping
–Proximity
–Similarity
–Continuity
–Connectedness
–Closure
Form Perception
Grouping
Form Perception
Grouping
Form Perception
Grouping
Form Perception
Grouping
Form Perception
Grouping - Closure
2) Depth Perception
– Estimating
distance
– Visual Cliff
– Binocular Cues
– Monocular Cues
Depth Perception
A. Binocular
Cues
– Retinal disparity—greater disparity between two
objects the closer they are.
– 3D technology
Depth Perception
B. Mononocular Cues
• Monocular cues
–Depth
perception cues
from one eye.
Depth Perception
Mononocular Cues
• Monocular cues
– Relative height
– Relative size
– Interposition
– Linear perspective
– Relative motion
– Light and shadow
Depth Perception
Monocular Cues – Relative Height:
(elevation) lower=closer
Depth Perception
Mononocular Cues – Relative Size
Depth Perception
Mononocular Cues - Interposition
Depth Perception
Mononocular Cues – Linear Perspective
Depth Perception
Mononocular Cues – Relative Motion
Depth Perception
Mononocular Cues – Light and Shadow
3) Motion Perception
• Stroboscopic
movement
• Phi
phenomenon
4) Perceptual Constancy
• Perceptual
Constancy
• Shape/size
• Lightness
• Color
Perceptual Constancy
a. ) shape and Size Constancies
Ames Room
Ames Room
Perceptual Constancy
B) Lightness Constancy
• Lightness
constancy
–Brightness
constancy
–Relative
luminance
Perceptual Constancy
C) Color constancy
–Surrounding
context
–Surrounding
objects
Perceptual Interpretation
Perceptual Adaptation
–Displacement
goggles
–We have
amazing abilities
to adapt to
distortion
Perceptual Set
–Mental
predisposition
–Schemas
Perceptual Set
Context Effects
Perceptual Set
Emotion and Motivation
• Motivation on
perception
• “The Bank Job”
• Emotions on
perception
Perception is a Biopsychosocial
Phenomenon