Sight
Hearing
Smell
Taste
Touch
Vestibular senses
Actually more than 5 senses
Basic Five: vision, hearing,
taste, smell and touch
Several skin senses
Internal senses: vestibular and
kinesthetic
Working alone,
write a short
description of
this scene.
Include what
is happening
and why you
think it is
happening. What
senses are the
characters using?
I hate
Simoncini!
May lice
cover his
ugly body.
Chapter project: You have
I hate his
projects. I wish I
could CHOOSE
to punch him in
his big nose.
Why did
I take
this
choicesstupid
course?
The initial electrical activity is a
sensation,
sensation: a stimulus (colors,
forms, sounds, smells, tastes, etc.)
that activates a receptor.
Physical change in external or internal
environments triggers chemical,
electrical and mechanical activity in
sense receptors.
Complex processing by nervous system
Pattern of activity in part of brain
The initial electrical activity is a
sensation,
sensation: a stimulus (colors,
forms, sounds, smells, tastes, etc.)
that activates a receptor.
A perception is: a series of organized
sensory information that creates
meaningful stimuli.
+
=
Each type of sensory receptor takes
some sort of external stimulus . . .
. . . and converts it into a chemicalelectrical message that can be
understood by the brain (transduction.)
Transduction:
sensory process
that converts
physical energy
into the form
of neural
messages.
Transduction (smell example)
Step 1:
Transform one form of
energy to another—detection
by a sensory neuron of a
physical stimulus
Stimulus: food aroma
Nose detects the stimulus
(aroma)
Transduction
Step 2:
When the
appropriate
stimulus (aroma)
reaches a sense
organ (Niki’s
nose), it activates
specialized
neurons called
receptors
Transduction
Step 3:
Receptors convert their
excitation into a nerve
signal that travels
along a sensory pathway to specialized
sensory processing
areas of the brain (in all but smell, the
signal travels by way of the thalamus)
Transduction
Stimulus = any aspect of or
change in the environment to
which an organism responds.
Stimuli measured many ways:
duration, intensity, wavelength
The senses
are most responsive to increases
and decreases; to new events
rather than ongoing, unchanging
stimulation
Sensory Adaptation
The senses adapt, or adjust, to
constant levels of stimulation.
Darkness
Noisy
streets
Cold pools
Smelly rooms
Sensations occur any time one
stimulus activates a receptor.
A combination of sensations plus
your past experience=perception
Absolute threshold --the minimum
amount of physical energy
required to produce a sensation
Hi, I’m a typical science
teacher and here are some
cool facts about absolute
threshold.
A candle flame can be seen 30miles away on a dark, clear
night
The ticking of a watch can be
heard 20 feet away under quiet
conditions.
Perfume can be detected when
one drop is put in a three-room
apartment.
The difference threshold --the minimum
amount of physical energy change
required to produce a change in sensation
Weber’s Law --the larger or
stronger a stimulus, the larger
the change required for an
observer to experience a
noticeable difference.
I/I=k
Fechner’s Law
Expresses the relationship between
actual magnitude of the stimulus and
its perceived magnitude. An increase
in physical magnitude of a stimulus
progressively produces smaller
increases in perceived magnitude
S = k log R
(S=sensation, R = stimulus, k = a
constant that differs for each sensory
modality)
Steven’s Power Law
a
S=kI
S = sensation; k = a constant,
I = stimulus intensity
a = a power exponent that depends on the
sense being measured
Addresses why Fechner’s law cannot
account for some changes in stimulus
detection, and works for a variety of
stimuli (viz. pain and temperature.)
Signal Detection Theory
Disputes absolute threshold
No sharp boundary between stimuli that
you can perceive and stimuli that you cannot
perceive
Detection thresholds involve
recognizing some stimulus
against a background of
competing stimuli
Signal Detection Theory
Processing stimuli
Pre-attentive process—extracting
information automatically and
simultaneously when presented
with stimuli
Attentive process—considers only one
part of the stimuli presented at a time
Signal Detection Theory
The Stroop Interference Effect (Attentive)
Step 1: name the colors in boxes at left rapidly
Step 2: read words at right rapidly
Step 3: name the colors at right rapidly
Hi students, I’m Mrs.
Science Teacher. Often
times subliminal messages
affect our perceptions of
things.
Subliminal: from the Latin
words sub (below) and
limen (threshold.) Subliminal
messages are brief visual or
auditory messages presented
below the absolute threshold;
there is a less than 50%
chance they will be perceived.
Very good, foxy lady. Let’s start
by discussing James Vicary and
his 1957 experiment.
No controlled research has
ever shown that subliminal
messages delivered to a
mass audience can Influence
people’s buying habits.
She is so hot she
sizzles. WOW!
Here is an example of
subliminal influences.
Abbey Road
Sergeant Pepper’s Lonely Heart’s Club Band
Often when television or
print ads appear, they
incorporate certain
subliminal advertising
techniques.
Name Calling: using negative
labels to discredit a
competitor
Glittering generalities: broad
statements that appeal to
emotions
Here are some more
subliminal advertising
techniques.
Card stacking—slanting facts
Plain folks—using folksy
language
Transfer: connecting a product with someone
or something that is admired
Bandwagon: Appealing to people’s desire to
“go with the crowd.”
Now, form into
groups and discuss
each of the six
subliminal
advertising
techniques. Think
about examples of
each: name calling,
glittering
generalities, card
stacking, plain folks,
transfer, and
bandwagon. Be
prepared to discuss
your results with the
class.
He is
sooooo
hot!!!
Now you will have a
group or individual
activity (your choice)
so you can
demonstrate what
you have learned in
this chapter.
What a
foxy
lady!!!
And this
activity
should be
fun
because
we
science
people
always
have fun!
Television Commercial
30-60 Seconds
Dialog and action
Appeal to at least 1 sense
Factor in use of subliminals—
Name calling, Glittering generalities
Card stacking, Plain folks, Transfer
Bandwagon
Alternatives: sales poster, song, album
cover, etc, using the subliminals
Vision
I see you!!!
And you are
in a heap of
trouble!!!
Vision
Vision
Blind spot
Lack of receptors at the spot where the optic nerve
connects to the retina
Vision
Most studied of all the senses
Light enters via
the pupil
reaches the lens,
a flexible structure
that focuses light
on the retina
Vision
Retina contains two types of lightsensitive receptor cells:
Rods and cones
Those cells change light energy into
neuronal impulses, which then travel
via the optic nerve to the brain.
Vision
Cones require more light than rods
before they respond
75-150 million rods; 6-7 mil. cones
Only cones are sensitive to color
If all or some cones do not function
properly: color deficiency
8% Amer. men; 1% Amer. women
Vision
Blind spot
We look with our eyes, but see with our brain
We look with our eyes, but see with our brain
Sensing Colors
Trichromatic Theory
Opponent-Process
Theory
It’s time for an experiment.
HOOAH!!!
Rods & cones & peripheral vision
Hearing
If a tree falls in the forest, and no one is there
to hear it, does it make a sound?
Hearing
Depends on vibrations of the air,
called sound waves
Sound waves from the air pass
through various bones and fluids
to the inner ear
Hearing
Amplitude is the height of the sound wave,
while frequency is a measure of how
frequently the sound waves pass a
given point.
Hearing
Anvil
Hammer
Stirrup
1. Airborne sound waves must be relayed to the inner ear.
In this initial transformation, vibrating waves of air enter the
outer ear and strike the eardrum, or tympanic membrane. This
tightly stretched sheet of tissue transmits the vibrations to
three tiny bones: the hammer, anvil and stirrup
Hearing
Anvil
Hammer
Stirrup
2. These bones pass vibrations on to the primary organ of
hearing, the cochlea (in the inner ear)
b. The cochlea focuses the vibrations on the basilar membrane
Hearing
3. The basilar membrane converts the vibrations into neural
messages (the swaying of tiny hair cells on the vibrating basilar
membrane stimulates sensory nerve endings connected to the
hair cells.) The excited neurons transform the mechanical
vibrations of the basilar membrane into neural activity.
Hearing
4. Finally, the neural messages travel to the auditory cortex in the
brain—neural signals leave the cochlea in a bundle of neurons
called the auditory nerve. The neurons from the two ears meet
in the brain stem, which passes the auditory information to
both sides of the brain
Hearing
Hearing
Anvil
Hammer
Stirrup
Hearing
Pitch
20 cps to 20,000 cps
Hearing
The inner ear contains tiny, hairlike cells that move back & forth
Hair-like cells change sound
vibrations into neuronal signals
that travel, via the auditory nerve,
to the brain.
Hearing
Perception of loudness depends on
amplitude of vibrations in the air.
That amplitude, or sound-pressure
energy, is measured in decibels.
Softest
Sounds
0 dbls.
Loudest
ear can
detect:
140 dbl.
Hearing
Any sound over 110 dbls
can damage hearing . . .
. . . as can persistent
sounds as low as 80 dbls
Hearing
Timbre (pronounced
tam-ber): “tone color” or
the complex quality of
the sound wave.
Example: recognizing
your company
commander’s voice on
the radio.
Conduction
Conduction deafness:
deafness:
conduction of vibrations
has been negatively
affected
Nerve deafness:
Damage to auditory
nerve or one of
higher auditory
processing centers
Hearing
Some hearing loss comes as a result of
age, however.
Mosquito Ring Tone (Teen Buzz)
Presbycusis: aging ear; starting around
age 20, the human ear loses its ability
to hear tones in the highest human-range
frequencies (18-20 kHz) and as one
ages it becomes more difficult to detect
those sounds
Balance
Regulated by the vestibular system
inside the inner ear.
Three semicircular
canals containing fluid
Over stimulation can
cause dizziness or
motion sickness
Hey Hottie!
How about a
vestibular
experiment?
OK, you
gorgeous
hunk of a
woman.
Hearing
Anvil
Hammer
Stirrup
Balance
Regulated by the vestibular system
inside the inner ear.
Three semicircular
canals containing fluid
Over stimulation can
cause dizziness or
motion sickness
Meniere’s Syndrome
Labyrinthitis
Body Sensations
Kinesthesis—sense of movement and body
positions
Cooperates with the vestibular and visual
senses to maintain posture and balance
Sensation of kinesthesis comes from receptors
in/near muscles, etc.
Smell and Taste
The chemical senses: their receptors
are sensitive to chemical molecules
rather than to light energy or sound
waves
Smell: molecules, via vapors, make
contact with a special membrane in
upper nasal passages—the olfactory
bulb--where smell receptors are located,
and sent directly to the limbic system.
You may recall that we used
smell to describe Transduction
Step 1:
Transform one form of
energy to another—detection
by a sensory neuron of a
physical stimulus
Stimulus: food aroma
Nose detects the stimulus
(aroma)
Transduction
Step 2:
When the
appropriate
stimulus (aroma)
reaches a sense
organ (Niki’s
nose), it activates
specialized
neurons called
receptors
Transduction
Step 3:
Receptors convert their
excitation into a nerve
signal that travels
along a sensory pathway, via the Thalamus,
to specialized sensory
processing areas of
the brain
Transduction
Smell and Taste
Those receptors send messages
about smells via the olfactory
nerve to the brain.
Taste: appropriate
chemicals must
stimulate receptors in
the taste buds of your tongue
Smell Disorders
Anosmia: loss of the sense of smell
Hyposmia: decreased ability to smell
Phantosmia phantom odors, mostly
Phantosmia:
unpleasant (rotting flesh, smoke, etc.)
Dysosmia: things smell differently than
they should
Smell and Taste
Taste is actually produced by smell
Smell and Taste
Sensations of warmth, cold and
pressure . . .
. . . affect taste
Cold chili; hot soda pop; soggy chips
It’s time for another
experiment!
Taste controlled by smell
Sour,
salty,
Four primary sensory bitter
experiences
and
make up taste:
sweet
Recent research: umami (Asian)
Old theory re: smell: six qualities
Flowery, fruity, spicy, resinous,
putrid, and burned
Several smell theories, no conclusions
Smell and Taste
It’s time for another
experiment. HOOAH!!!
The taste buds
Bitter
Sour
Sweet
Salty
Sour
The Skin Senses
Receptors in the skin provide the
brain with four kinds of information
about the environment:
Pressure, warmth, cold, and pain
The Skin Senses
Connected to the somatosensory cortex,
located in the parietal lobes
The Skin Senses
Level of sensitivity varies on body
Fingertips—densely populated
with receptors: highly
sensitive—10 times more so
than on backs or calves
Back of calf—relatively few
receptors: less sensitive
It’s time for another
experiment!
Skin receptors—differences in
density based on body parts
The Skin Senses
Phantom limb
The Skin Senses
Pressure sensations can
serve as protection
Some skin
receptors are
particularly sensitive
to hot or cold stimuli.
Warm water on warm vs. cold day
The Skin Senses
Stimuli such as scratches, punctures,
severe pressure, heat, and cold can
produce pain.
Pain is an emergency
system that demands
immediate action. It
makes it possible to
prevent damage to your body.
The Skin Senses
Gate-Control Theory
Neurons with Myelin on axons,
faster messages—most sensory images to brain
The Skin Senses
Gate-Control Theory
Second route, smaller,
slow fibers, without Myelin
sheaths on axons, send
messages more slowly.
Competing messages
from fast fibers can block
pain messages in slow
fibers—can close a spinal
gate
The Skin Senses
Gate-Control Theory
When you hit your finger with
a hammer, you automatically
make use of the “gate” by
vigorously shaking your hand
to generate fast fiber signals
that block the pain. The “gate,” itself, probably
operates in a brain stem region called the
periaqueductal gray (PAG).
The Skin Senses
Controlling pain
Hypnosis
Placebos
Acupuncture
Acupuncture works because the needles, like placebos,
trigger the release of pain-killing endorphins. Although
we do not know precisely how the triggering mechanism
works, controlled studies do show that acupuncture
patients exhibit elevated endorphin levels.
The Skin Senses
The Placebo Effect
Expectation of pain
relief is enough to cause
the brain to release
painkilling endorphins
The episode of M*A*S*H entitled
“Major Topper,” March 27, 1978
People do not merely have sensory
experiences; we perceive objects.
Brain receives information from the
senses and interprets it into meaningful
experiences—unconsciously.
Process of
perception
Feature Detectors
in the cerebral cortex
cells specialize in
extracting certain
features of a
stimulus—our brains
have specialized
groups of cells dedicated to the detection
of specific stimulus features (length,
slant, color, boundary)
The binding problem
Process used by the brain to bind
(combine) results of many sensory
operations into a single precept.
People’s faces
Bottom-up and Top-down Processing
Perception: take sensory data into the
system through receptors and sends
it upward to the cortex
Bottom-up: perceptual analysis that
emphasizes characteristics of the
stimulus, rather than our concepts and
expectations
Bottom-up and Top-down Processing
Top-down: perceivers goals, past
experience, knowledge, expectations,
memory, motivations, or cultural background in the interpretation of an object
or event
Perceptual Constancy
Ability to recognize the same object
as remaining constant under different
conditions
Illusions are
created when
perceptual
cues are
distorted so
that our brains
cannot
correctly
interpret
space, size
and depth
cues. Many
illusions are
optical
illusions.
Sometimes our
perceptions can
be incorrect.
Those situations
are called
illusions.
To demonstrate, we
shall now observe some
optical illusions from the
Internet. Here are some
more.
Brain continuously trying to build
“wholes” out of the confusion of
stimuli that bombards the senses.
The “whole” experience
that comes from
organizing bits and
pieces of information
into meaningful objects
and patterns is called
Gestalt.
Types of Perception
Figure-ground perception—ability to
properly discriminate between
figure and ground
The fact that we can perceive a
single pattern in more than one way
shows that we are not passive
receivers of stimuli
Often perceptions are not based
entirely on current sensory
information
Hear a barking dog in
the distance. . . assume
it is a dog.
Perceptual influence:
phenomenon of filling in
gaps in what senses tell us.
Perception is learned behavior
Takes babies 7-8 months to learn
to recognize different people.
Gestalt: German term meaning
pattern or configuration
Scientists try to identify principles
brain uses in constructing
perceptions
Five principles: similarity, proximity,
continuity, simplicity, and closure
Similarity: when similar and dissimilar
objects are mingled, we see the similar
objects as groups
x o x o x
Home
team
in red
uniforms
Visiting
team in
white
uniforms
x
x
x
x
o
o
o
o
x
x
x
x
o
o
o
o
x
x
x
x
Proximity: perceive a number of similar
objects as groups or sets
Proximity: perceive a number of similar
objects as groups or sets
Do you see a lawn or
individual blades of grass?
Do you see pine trees
or individual needles?
Example: in music we do not hear
individual notes as much as we hear
melodies (notes in proximity to one
another)
Continuity: we tend to see continuous
patterns, not disrupted ones
Baseball venue rather than various
shapes (diamond infield, square bases,
etc.)
Following a sound of a
particular voice or
instrument when many
other sounds are
occurring is due to
similarity and continuity
Law of common fate: we tend to group
similar objects together that share a
common motion or destination
Runners vs. spectators
Simplicity: we see the simplest patterns
possible;
the law of
A
bird
Pragnanz
in the
the hand
Closure: when we see a familiar pattern
or shape with some missing parts,
we fill in the gaps.
Gestalt principles of organization
help to explain how we group our
sensations and fill gaps in order to
make sense of our world.
Vision
Two eyes
two images
Combination of 2 images into one
is called binocular fusion
Images differ on each retina
Retinal disparity
Hey-yo! Let’s do another
experiment—this one is
about retinal disparity.
Pen or pencil
Hold 12-inches in front of
face.
Both eyes, then left eye
closed, then right eye
closed. What happens?
Pilots’ Monocular Cues
 Relative size
 Light and shadow
 Interposition
 Relative motion
 Atmospheric perspective
von Helmholtz Theory
Theory of learning-based inference
People use prior learning to interpret
new sensory information
Based on learning, people make
inferences (guesses or predictions) about what
sensations mean
Our perceptual interpretations are, in effect,
hypotheses about our sensations
Extrasensory Perception (ESP)
Receiving information about the
world through other than the
normal senses.
Paranormal
experience—a sense
beyond the basic
5 senses.
Experienced with thoughts, not body
sensations—therefore very
controversial
Major types of ESP:
Telepathy—ability to read another’s
thoughts
Clairvoyance—ability to “see” events
or objects happening somewhere
else
Precognition—ability to see the
future
Major types of ESP (continued)
Retrocognition—ability to see
into the distant past
Mediumship—the ability to
channel dead spirits
Psychometry—ability to read
information about a person
or place by touching a
physical object
Parapsychology:
“Father:” J. B. Rhine
Zener Card Experiments—
deck of 25 cards, each with
one of 5 patterns