Sensation and Perception by a6gn01

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									Sensation and
   Chapter 5
               Journal #3
 Why   are some people color deficient?

In other words, what is it about their eyes
  that makes some people color blind, but
  allows others to see all colors fine?
               Journal #2
 Name   the different senses.
              Journal #4
   you had to lose one sense, what would it
 If
  be and why?
              Journal #5
 What would happen if you did not have
 your vestibular sense?

 Whatif you didn’t have your kinesthetic
               Journal #6
 What Principles of Perceptual
  Organization do the following portray?
 1- ………. 2- ……… 3-
    ……….       llllllllllll
    ……….       ……..
               Journal #7
     at least three of the ways your brain
 List
  uses to tell depth perception.
                Journal #8
 What   are illusions and why do they work?
We are going to study Chapter 5:
Sensation and Perception. Watch
 this video and be prepared to
    answer some questions.
             Video Reactions
You may work with a partner, but must have your
  own sheet to turn in. Read over the questions and
  watch the video again.
What did you see and hear (these are 2 of our
  senses used to receive information)?
Perception is the organization of sensory
  information (sight and sound in this case) into
  meaningful experiences. How do you explain what
  you saw? We know it can’t be real. Right???
  (Write at least a 5 sentence paragraph)
Sensation- What occurs when
a stimulus activates a receptor

Perception- The organization of
   sensory information into
   meaningful experiences

   Sensation + Experience=
 Stimulus:  Any aspect or change in the
    environment to which an organism

 Outside    world----- sensation-----perception
      bee               sting     time to run

   Stimuli come before sensation, but the line
    between sensations and perceptions is fuzzy.
 Psychophysics:     the (psychological)
  study of the relationships between sensory
  experiences and the physical stimuli that
  cause them.
 The goal is to learn to measure the stimuli
  then study the relationship between that
  stimuli and the effect it causes.
    Threshold:    how much of a stimulus
    is needed to cause an effect which
    can be noticed?
         Look at the picture to the right.
         What is it?
         Now we will find out!!

    Absolute Threshold: the
     minimum physical energy required
     to produce a sensation
Produces a response 50% of the time (or

    Difference Threshold: The
     minimum physical energy required
     to produce a change in sensation.
Produces a response 50% of the time (or
 Sensory Differences and Ratios
Someone sits on your lap. Someone hands her a
  feather, then a bowling ball.

Often it is the change that is noticed, not the
   presence or absence of a stimulus.
Is the above an example of difference threshold or
   absolute threshold?
      Sensory Differences and Ratios
   Weber’s Law: the larger or stronger a stimulus, the
    larger the change required for an observer to notice
    that anything has happened. Would this part of the
    difference threshold or absolute threshold?

   Listen to the video about Weber’s law and sound
    1st sound 50% increase (100-150, +50)
                    can hear
    2nd sound 5% increase (1000-1050, +50)
                    can’t hear
    3rd sound is 50% increase (1000-1500, + 500)
                    can hear

    Some sensations only require small adjustments
    to yield huge changes in perception.
    See following pictures?
  Study the picture trying to
remember everything you see!
What is missing? What is new?
What is missing now?
       Remember the Law!
 Weber’s   Law: the larger or stronger a
  stimulus, the larger the change required
  for an observer to notice that anything has
 This is why the last picture was easier
  even though the same number of objects
  were removed from the pictures!
              Journal #1
 What’s the difference between sensation
  and perception? (3-5 sentences)
 What is a threshold? Name the two types
  and explain how they differ.
 How do you feel about subliminal
  messages in advertising in print and TV?
  Would you use it to sale your product?
          Subliminal Messages
   Sub (below) limen (threshold)- it is thought
    that subliminal messages are thought to be
    only sensed by our unconscious mind
   You could say the messages are below the
    absolute conscious threshold
   Examples include- Messages hidden in video in
    movies and TV, pictures or music
   Do you have a problem with this? What, if any,
    are the dangers?
   Read Book Page 109-110
          Subliminal Examples
Hidden Advertisement     Backmasking
Subliminal Examples
     Advertising Pictures
           Sensory Adaptation
   The senses are tuned
    to change. They
    quickly adapt to a
    new level, then get
    bored and look for
    change. See video!
         Sensory Adaptation
 What do have you adapted to?
 What do you seem to have problems
  adapting to?
            Sensory Adaptation
   Complete the sensory adaptation activity
    using the yellow paper covered half way with
    white. Stare at the dot for I minute and see
    what happens!!
         Sensory Adaptation
     next to a highway--- get used to the
 Live

 Move to the desert---- it looks barren, your
 eyes adapt, and you see many levels of
 Motivation and Signal Detection

 Your
     ability to detect a signal,
 depend on motivation.
    Motivation and Signal Detection
   If you are afraid of the woods, you will hear more
    noises at night than others.

 If you are happy,
you will see others’
smiles more readily.

   If you think you are a lousy public speaker, you
    will be sensitive to negative cues from your
  Motivation and Signal Detection

 Signal Detection Theory: abandons the
 notion that there is a single, absolute
 threshold for a stimulus. Instead, the
 threshold varies according to the
 surrounding circumstances.
              The Senses
 Name   our senses (8).
                The Senses
 Did   you get all ?

Check your answers-
 Vision,Hearing, taste, smell,
 touch, skin senses, vistibular,
The Senses- Group Presentations
 Groups-  Vision 1 (pg. 115-116), Vision 2
  (pg. 116 color deficiency-117), Hearing,
  Smell and taste, skin senses, balance and
  body sensations
 Requirements:
     Power point slides (2)
     Share 10 facts
     3 T/F and 3 fill in the blank questions
     Everyone presents
Jimmy Albright’s Story- How
well could you play basketball
if you were legally blind?
Complete Vision Activities
Activity 1 and 2: Blind spots
Activity 3: Peripheral Vision
and Color
1. Why do you think you have a blind
                                            Clue- We have cones for
2. Why don’t we normally realize we         color and rods for black and
have a blind spot?                          white. Rods and cones are
3. Why do we not see color as well in our   receptors and line the retina.
peripheral vision?
4. For Review- Complete the activity
under sensory adaptation. Give two
other examples of sensory adaptation.
                           The most studied of all the senses.
Light enters through the pupil and reaches the lens which focuses light on the

   The rods and cones convert the light energy into electrical (neuronal)
    impulses which then travel over the optic nerve to the brain.
 The retina in back contains two types of
  receptor cells: rods and cones.
 Cones= color film
     Require more light, work best in the daytime,
      sensitive to color.
 Rods=    black and white film
  Require less light, work best at night,
   insensitive to color.
  Many more rods than cones [ 7 million vs. 150
   million; 1:20]
   Color Deficiency: a hereditary defect.
       Evolutionary?? Camouflage idea – color blind soldiers
        see camouflage= survival
When some or not all of a person’s cones do not
 function properly.

Most “color blind” are only partially color blind.
Red /green look similar most common (especially
Yellow/blue look similar
 Test   you sight for red/green.
     In your journal write color blindness activity.
     Number 1-7
     Write down the number you see in the circles.
      If you do not see a number write down spots.
     Do not share the number you see.
1.        2.

3.        4.
5.        6.

Normal Color Vision                                 Red-Green Color Blind

                         Left           Right                     Left      Right

Top                      25             29          Top           25        Spots

Middle                   45             56          Middle        Spots     56

Bottom                   6              8           Bottom        Spots     Spots

Another interesting color blindness test is below
       The  last test is simpler.
The individual with normal color vision
will see a 5 revealed in the dot pattern.
An individual with Red/Green (the most
 common) color blindness will see a 2
          revealed in the dots.
    Binocular Fusion and Stereopsis
   Binocular Fusion= the combining of two
    images into one.
   Retinal Disparity= the different view with
    which one sees an object from each eye.
   Stereopsis= the ability to see depth (as a
    result of your retinal disparity).

Binocular fusion +retinal disparity+ stereopsis=
            ability to see and function
3-D Activity

Binocular Fusion Test- Page 116 Activitiy 5.6

Eye Dominance Test
  Is your right eye or left eye dominant? Make a box with your
  fingers and extend your arms away from your body. Now, focus
  on an object in the room by making sure it is in the center of
  the finger box. Slowly mover the box closer to your face while
  keeping the object centered in the box. Whatever eye your
  finger box is over is your dominant eye.

  Why is this important?

3-D Image
 The auditory nerve carries impulses from
 the inner ear to the brain, resulting in the
 sensation of sound.

Parts of the ear:
 Ear canal, eardrum, malleus(hammer),
  incus(anvil), stapes(stirrup),
cochlea, auditory nerve.
   The auditory nerve carries
    impulses from the inner ear
    to the brain, resulting in the
    sensation of sound.

Parts of the ear:
 Ear canal, eardrum,
  incus(anvil), stapes(stirrup),
  cochlea, auditory nerve.
 anvil - (also called the incus) a tiny bone
that passes vibrations from the hammer
                                                nerves - these carry electro-chemical
to the stirrup.
                                               signals from the inner ear (the cochlea)
cochlea - a spiral-shaped, fluid-filled
                                               to the brain.
inner ear structure; it is lined with cilia
                                               outer ear canal - the tube through whic
(tiny hairs) that move when vibrated and
                                               sound travels to the eardrum.
cause a nerve impulse to form.
                                               pinna - (also called the auricle) the
eardrum - (also called the tympanic
                                               visible part of the outer ear. It collects
membrane) a thin membrane that
                                               sound and directs it into the outer ear
vibrates when sound waves reach it.
Eustachian tube - a tube that connects
                                               semicircular canals - three loops of
the middle ear to the back of the nose; it
                                               fluid-filled tubes that are attached to the
equalizes the pressure between the
                                               cochlea in the inner ear. They help us
middle ear and the air outside. When you
                                               maintain our sense of balance.
"pop" your ears as you change altitude
                                               stirrup - (also called the stapes) a tiny,
(going up a mountain or in an airplane),
                                               U-shaped bone that passes vibrations
you are equalizing the air pressure in
                                               from the stirrup to the cochlea. This is th
your middle ear.
                                               smallest bone in the human body (it is
hammer - (also called the malleus) a tiny
                                               0.25 to 0.33 cm long).
bone that passes vibrations from the
eardrum to the anvil.
   How loud something is depends on the
    amplitude of the sound waves it creates.

       Loudness is measured in decibels
         • Conversation= 60 vacuum= 80 jet engine=140
           Click Here to Hear Decibels
 Any painful sound, if continued, causes hearing
           • Pain occurs at 130 decibels, damage occurs at
 Pitch depends on the frequency of the sound
  Low frequency= bass’
  High Frequency= shrill squeak
Click here to hear frequency
You can hear more than one pitch at a time.
  two keys on a piano--- you hear both, not just a
  combined pitch.

Your ears work to “locate” the sounds.
            Smell and Taste
             “The Chemical Senses”
The chemical molecules on odor reach the odor
   receptors in the upper passages of your nose.
   These receptors convert chemical sensations
   into nerve impulses through the olfactory
   nerve to the brain.

There may be 1,000 olfactory receptors in your
   nose, with each receptor capable of
   pinpointing its own, unique odor.
              Smell and Taste
   For taste to occur, the chemical molecules of the
    food you eat activate the taste buds on your
    tongue. These taste buds relay taste
    information to your brain. Along with information
    about the temperature, density, and texture of
    the food you eat.

 Four primary taste
experiences: sour,
salty, bitter, sweet.
              Smell and Taste
     sense of taste is enhanced by you
 Your
 sense of smell.
     Blocked nose--- bland tasting food.

     taste experiences also enhanced by
 Your
     Cold oatmeal, steaming hot Coca Cola.
 And   Texture
     Pudding versus granola bars.
                 Smell and Taste
   Taste Test???

   Questions-
       1. What were your results?
       2. If you or someone else was able to identify the
        tastes of one or more of the candies how did they do
        this and how long did it take?
       3. What taste were we testing (bitter, sweet, sour or
       4. Since we were testing only one of the above how
        do we know the difference between the flavors?
             The Skin Senses
 Atleast four kinds of sensations you get
 through your skin:
      Pressure
      Warmth
      Cold
      Pain
         The Skin Senses
Pressure sensitivity in fingertips vs. middle of

Temperature sensitivity is relative
 heat one hand, cool the other, place both in
 neutral water--- one hot and one cold hand.

Pain helps protect you from harm
 for the most part, you do not “adapt” to pain.
Your sense of balance comes from the vestibular system
  inside your inner ear.

Inside your ear you have three semi-circular, liquid-filled
   canals called the posterior, superior, and lateral canals.
   {tubes lined with hair and filled with water}

When you start, stop, turn, etc the water in the tubes
 sloshes back, forth, around, etc. Your hairs feel the
 movement and transmit the feeling to the brain through
 neural impulses.
Balance Demonstration
1.   How long will you balance on your left and your right?
2.   What will the class average be?
3.   Will a girl or boy win?
Perform Test
1.   Stand on one leg and close your eyes. When you hop, spin or
     touch your foot on the ground you are done.
2.   Now we will try the other leg.
Post Test
1.   Analyze # 1-3.
2.   Did right handed people do better on right or left? What
     about lefties?
            Body Sensations
Kinesthesis is the sense of movement and body

It comes from sensors in the muscles, tendons,
   and joints which control body movement.
   - Without Kinesthesis you would have to watch
   your feet as you walked.
   - watch your hands to make sure they did what
   you told them, etc.

Kinesthesis + balance + sight= control balance
  and posture.
             Body Sensations
 Another type of kinesthetic sense tells you
 what is going on inside your body.
     Did you eat to much?
     Do you have a headache?
     Did you get to much caffeine in your coffee?
     Was that last hamburger you ate to raw?

 Referredpain: indicators of internal pain
 send signals to the wrong locations.
              Body Sensations
   Spin around in place for 5 seconds and try to
    stand on one leg with your eyes shut. Also see if
    you are dizzy or have a tummy ache. Keep
    doing this by adding 5 seconds each time. Make
    sure to stop before you get sick. On your last
    time try and walk a straight line to test your

   How did it go? Do you feel sick? How is your
    head and tummy? Were you able to walk a
    straight line?

 The brain receives information from the
senses and organizes and interprets it into
  meaningful experiences. This is called
         Principles of Perceptual
  The brain tries to make sense out of whatever it sees.

Gestalt: In perception, the experience that comes
  from organizing bits and pieces of information
  into meaningful wholes.
 The whole becomes more than that sum of its
 In German Gestalt means pattern or
 Gestalt psychologists try to identify the principles
  the brain uses to construct perception.
 We apparently group our sensations to “fill in the
  gaps” to make sense of what we perceive.
          Principles of Perceptual
1   OXXXXXXXXXX   2                           3
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          Principles of Perceptual
   The law of similarity says that we will tend to
    group similar items together, to see them as
    forming a gestalt, within a larger form. Here is a
    simple typographic example:
        Principles of Perceptual
 The  law of closure says that, if something
 is missing in an otherwise complete figure,
 we will tend to add it. A triangle, for
 example, with a small part of its edge
 missing, will still be seen as a triangle. We
 will “close” the gap.
        Principles of Perceptual
 Another law is the law of proximity. Things that
  are close together as seen as belonging
  together. For example...
You are much more likely to see three lines of
  close-together *’s than 14 vertical collections of
  3 *’s each.
          Principles of Perceptual
   Next, there’s the law of symmetry. Take a look
    at this example:

            [   ][   ][   ][   ][   ]

Despite the pressure of proximity to group the
 brackets nearest each other together, symmetry
 overwhelms our perception and makes us see
 them as pairs of symmetrical brackets.
          Principles of Perceptual
   Another law is the law of continuity. When we
    can see a line, for example, as continuing
    through another line, rather than stopping and
    starting, we will do so, as in this example, which
    we see as composed of two lines, not as a
    combination of two angles...:
    Figure-Ground Perception
 Figure-Ground   Perception is the ability
 to discriminate properly between figure
 and ground.

 With3-Dimensional objects, you can
 easily tell the difference between the figure
 and its background. With 2-dimensional
 objects it is more difficult.
Figure-Ground Perception
Figure-Ground Perception
Figure-Ground Perception
     Figure-Ground Perception
 Figure-ground perception also applies to

A familiar voice becomes figure, a room
 full of voices becomes ground.

A melody you love becomes figure, its
 symphony becomes ground.
         Perceptual Inference
 PerceptualInference: filling in the gaps in
 what our senses tell us.

     You hear coffee perking and assume it
      smells good.
     You hear a toilet flush and assume
      someone just went to the bathroom.
     You push an elevator button and assume
      the elevator will come.
         Perceptual Inference
    Write in your notebook Perceptual
     Inference class activity.
    Complete the following the following
1.   ()
2.   []
3.   []
4.   /_\
            Perceptual Inference
Which triangle do you see? I see   A transparent surface is suggested
a video game character also. Do    by the subjective contour.
you know which one?
        Perceptual Inference
 Depends   on experience, but some
  perceptual inferences may be innate (in-
 Figure 5.14, infant on cliff
           Learning to Perceive
 Babies eventually learn to discern faces as
 being linked to specific individuals by 7 or
 8 months.

 Activeinvolvement in the environment is
 required to develop perception.
     Figure 5.15, pg. 123
              Learning to Perceive
   Examples that illustrate the need for active involvement to develop

Figure 5.15, pg. 123, Kittens, with one involved and the other passive.
   Kittens raised in dark for 2 weeks. Then divided into 2 groups. The
   pairs were put in a cylinder. One kitten could walk around the other
   was only in a cart being pulled by the walking kitten. The walker
   developed depth perception, the other didn’t. Later, the passive
   kitten did develop depth perception when allowed to walk around.

In some rare cases blind humans have had their sight restored. These
    newly sighted persons had difficulty understanding what it was they
    were looking at even after 6 months.
             Depth Perception
 Peopleuse many cues to help them
 determine depth.
     Size- bigger is seen as closer
     Interposition: the partial blocking of a more
      distant object by a nearer object.
     Shadows: give you clues about shape and
     Texture: density gradient- more detail is seen
      as closer
            Depth Perception
•   Aerial Perspective (or blurring): blue caste is seen
    as farther away.
   Atmospheric perspective (or graying): gray caste
    appears farther away.
   Linear Perspective: assumes that parallel lines
    eventually meet on the horizon.
   Blurring: occurs to near objects if you look beyond
    them, to far objects if you look short.
   Accommodation: the lens in your eye thickens to
    see near objects, thins to see far ones.
          Depth Perception
 In your notebook write Depth Perception
  activity. Number 1-6.
 List the principle that each picture uses to
  show depth.
 1.
 2.
 3.

 4.-----------------
 5.

 6.   -------------------
     Depth Perception- SIRDS
 This is the kind of stereogram where a shape is
  hidden in a field of dots or patterns.
 The next two pictures are single-image random
  dot stereograms or SIRDS which will illustrate
  how depth is generated using binocular
 For example, there is the binocular depth cue
  called disparity. Disparity arises from the fact
  that our two eyes have a slightly different view of
  the world. To allow you to see disparity requires
  either real depth or two images developed as if
  from different positions like our eyes.
Depth Perception
Depth Perception
Depth Perception
                    Depth Perception
Some of the cues you use to determine depth are internal cues:
   Convergence: eyes turn inward to see close objects.
   Retinal Disparity: (discussed earlier)
     •Motion parallax- objects appear to move when you move your head from
     side to side.
     •Relative Motion: look at mountains, animals seem to be moving in the
     opposite direction: look at animals and mountains appear to be moving with
 Constancy:   the tendency to perceive
  certain objects in the same way,
  regardless of changing angle, distance, or
 Size Constancy: a person approaches
  you. The actual image is getting larger,
  but you perceive the person as one,
  unchanging size.
 Figures on page 125.
          incorrect perceptions that occur
 Illusions:
  when sensations are distorted.

 Lookat each illusion and write what is
•   Motion aftereffect
    •   When strongly stimulated by motion in a
        particular direction, the subset of motion
        detectors that respond to that motion become
    •   When the stimulus is removed, the motion
        detectors for the opposite direction produce a
        stronger signal for a few seconds, until the
        fatigued motion detectors recover. This is
        thought to be the source of the motion
•   Motion aftereffect
    •   Examples
        • Waterfalls
        • Spirals
          •   Cover one eye and look at the spiral
              and then look at the object only with
              the eye that was covered. What does
              this tell us?
   This opponent process theory states that the human
    visual system interprets color information by processing
    signals from cones and rods in an antagonistic manner.
    The opponent color theory suggests that there are three
    opponent channels: red versus cyan, blue versus yellow,
    and black versus white. Responses to one color of an
    opponent channel are antagonistic to those to the other
    color. Therefore, a green image will produce a magenta
    afterimage. The green color tires out the green
    photoreceptors, so they produce a weaker signal.
    Anything resulting in less green, is interpreted as its
    paired primary color, which is magenta.

Website   illusions
       Extrasensory Perception
   Extrasensory Perception: receiving information
    about the world through channels other than the
    normal senses.

PROBLEM- Some “ESP” experiences are based
 on premonitions which prove to be true, but
 these premonitions are not offset by the many
 times that our premonitions turn out to be false.
 This provides false evidence of the existence of
     Extrasensory Perception
 Parapsychologist   J.B. Rhine (around
 1930) conducted scientific tests of people
 who potentially possessed ESP skills. He
 used special decks of cards, “senders”
 and “receivers” to track ESP. He found
 that some people did, in fact, possess the
 ability to “transmit” images from the cards
 at a rate higher than chance.
      Extrasensory Perception
It is hard to duplicate ESP research in a laboratory.
    Whenever attempts have been made the results
    have been inconclusive, suspect, or weak.

Charles Tart (1976) screened 1500 college
 students who made 7500 guesses as to whether
 or not one of four lights would come on. The
 lights were randomly generated, so they should
 have been right 25% of the time. They were
 correct 26.8%, what could have accounted for
 the difference? To large to be chance.
        Extrasensory Perception
   When strict controls are placed on ESP
    experiments, the data tends to “go away,” but
    supporters of ESP claim that laboratories are not
    conducive to ESP experience, that labs are to
    sterile and unfriendly toward ESP. In their view
    ESP works best in highly emotional
    circumstances– exactly the kinds of experiences
    which do not take place in a laboratory.

   Until ESP can be duplicated in a laboratory,
    scientists will remain skeptical about its
      Extrasensory Perception
Your turn.
1. Get a partner, piece of paper, and something
   to write with. Sit facing your partner.
2. Choose who will be the “sender” and the
3. Ask the receiver what card you are looking at.
   Record if they were right or wrong. Do this for
   10 cards.
4. Switch places.
5. Figure out the % they got right. Is it above
          TEST TIME
             THE TEST.

    AREN’T YOU EXCITED!?!?!?!?!

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