Transcript document

Sight
Hearing
Smell
Taste
Touch
Vestibular senses
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.
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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)
Stimulus = any aspect of or
change in the environment to
which an organism responds.
Stimuli measured many ways:
duration, intensity, wavelength
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
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.
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
Smelly rooms
Let’s do
the
sensory
adaptation
Experiment
On p. 212.
A person’s ability to
detect a stimulus
also depends on
motivation.
Individuals decide to receive stimuli,
although that decision-making
process is usually entirely
unconscious, and is often based on
feelings or expectations.
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
Actually more than 5 senses
Basic Five: vision, hearing,
taste, smell and touch
Several skin senses
Internal senses: vestibular and
kinesthetic
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. The process
of transduction.
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
We psychology teachers
love experiments. So let’s
do some about our eyes.
Turn to p. 216 in the
textbook.
We all have blind spots
Color deficiencies
Negative afterimages
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?
We look with our eyes, but see with our brain
We look with our eyes, but see with our brain
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
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
Anvil
Hammer
Stirrup
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
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
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 where smell
receptors are located.
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 path-way, via the
Thalamus, to specialized sensory
processing areas of the brain
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
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
Smell and Taste
Sensations of warmth, cold and
pressure . . .
. . . affect taste
Cold chili; hot soda pop; soggy chips
Smell and Taste
Taste is actually produced by smell
Please read from the
top of p. 220 to the
end of Section 2 on
p. 222. This is a 5minute exercise.
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
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
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.
Balance
Regulated by the vestibular system
inside the inner ear.
Three semicircular
canals containing fluid
Over stimulation can
cause dizziness or
motion sickness
Vestibular
Anvil
Hammer
Stirrup
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.
It’s time for a full DAY of
experiments. HOOAH!!!
Rods & cones & peripheral vision
The taste buds
Bitter
Sour
Sweet
Salty
Sour
It’s time for a full DAY of
experiments. HOOAH!!!
Rods & cones & peripheral vision
The taste buds
Taste controlled by smell
Skin receptors—differences in
density based on body parts
It’s time for a full DAY of
experiments. HOOAH!!!
Rods & cones & peripheral vision
The taste buds
Taste controlled by smell
Vision
People do not merely have sensory
experiences; we perceive objects.
Instructions: draw 9 evenly spaced dots on your paper
as shown above. Without lifting your pencil from the
paper, draw exactly 4 straight, connected lines that
will go through all nine dots, but through each dot
only once.
Instructions: draw 9 evenly spaced dots on your paper
as shown above. Without lifting your pencil from the
paper, draw exactly 4 straight, connected lines that
will go through all nine dots, but through each dot
only once.
Brain receives information from the
senses and interprets it into meaningful
experiences—unconsciously.
Process of
perception
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.
Gestalt: German term meaning
shape or configuration
Scientists try to identify principles
brain uses in constructing
perceptions
Five principles: proximity,
continuity, simplicity, closure
and similarity
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
Simplicity: we see the simplest shapes
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.
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
Gestalt principles of organization
help to explain how we group our
sensations and fill gaps in order to
make sense of our world.
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.
Hi students, 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.
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.
Now you will have a
group activity so
you can
demonstrate what
you have learned in
this chapter.
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
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.
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
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