Psychology Chapter 4

Monday October 17

  • Today’s Goal:  Sensation and Perception – The Basics
  • Learning Targets:  I can distinguish between sensation and perception, and explain how they contribute to an understanding of our environment
  • Bell Work: Journal - What senses do people have?
    • Discuss journal – At least 5 (vision, hearing, smell, taste, and touch) AND pressure, warmth, cold, pain, the position of our body, etc.
  • Hand back quizzes for students to see grade


Notes Chapter 4 Section 1 Sensation and Perception

In General:

  • Once we take in information with our senses, we do something with that information to interpret it.
    • This depends on many factors including the circumstances, our mood, our cultural background, etc.

Sensation and Perception: The Basics:

  • Sensation:  the stimulation of sensory receptors and the transmission of sensory information to the brain.
    • Sensation = the feeling
    • Sensory receptors are located in sensory organs such as the eyes, ears, etc.
    • The stimulation of senses is automatic and results from sources of energy like light and sounds or from the presence of chemicals as in smell and taste.
  • Perception:  the process of organizing and interpreting sensory information.
    • Perception = the interpretation of that feeling.
    • Perception reflects learning, expectations, and attitudes.

Absolute Threshold

  • Absolute Threshold:  The smallest amount of a particular stimulus that can be detected.
  • Absolute thresholds for humans have been determined for the sense of vision, hearing, smell, taste, and touch.
    • These can differ from person to person as some people are more sensitive to certain sensory stimuli than others are.
      • These differences stem from psychological and biological factors.
      • Absolute threshold chart



Electromagnetic energy

Rods and cones in retina

A candle flame viewed from a distance of about 30 miles on a dark night.


Sound waves

Hair cells of the inner ear

The ticking of a watch from about 20 feet away in a quiet room.


Chemical substances in the air

Receptors cells in the nose.

About one drop of perfume diffused throughout a small house.


Chemical substances in saliva

Taste buds on tongue

About 1 teaspoon of sugar dissolved in 2 gallons of water


Pressure on the skin

Nerve endings in the skin

The wing of a fly falling on a cheek from a distance of about 0.4 inch.


Difference Threshold

  • We need absolute thresholds low enough to see, hear, smell, and taste what is going on around us, but not so low we are overloaded with information we cannot use.
  • We also need to be able to detect small differences between stimuli-what makes one stimulus different then another?
  • Difference Threshold:  the minimum difference that an individual can detect between two stimuli.

Signal-Detection Theory

  • Signal-Detection Theory:  the idea that distinguishing sensory stimuli takes into account not only the strength of the stimuli, but also such elements as setting and one’s physical state, mood, and attitude.
    • Signal detection theory also considers psychological factors such as motivations, expectations, and learning.
    • We focus on what we consider important.

Sensory Adaptation

  • Sensory Adaptation:  the process by which an organism become more sensitive to stimuli that are low in magnitude and less sensitive to stimuli that are constant.
    • We are more sensitive to weak stimuli and less sensitive to unchanging stimuli.
    • Examples:
      • Hearing -- loud sound causes a small muscle attached to one of the bones of the inner ear to contract, reducing the transmission of sound vibrations to the inner ear, where the vibrations are detected. (This protective mechanism does not work well for sudden very loud noises such as rifle shots, as the muscle does not have time to contract before the intense vibrations pass through.)
      • Touch -- We quickly adapt to hot and cold stimulation, if it is not too intense. The bath that was almost too hot to enter soon feels too cool; similarly, the cold lake we jump into for a summer swim feels freezing at first, but soon feels only refreshingly cool.
      • Smell -- We can detect amazingly low concentrations of some chemicals in the air (e.g., perfumes) but although the perfume is still in the air about us, we quickly cease to detect it.   à demonstrate by spraying some body spray

Exit Ticket: 

  1.  How do sensation and perception affect people’s understanding of their environment?

Tuesday October 18

  • Today’s Goal:  Vision
  • Learning Targets:  Explain how the eye works to enable vision.
  • Bell Work: Write the following question in your journal:
    • What were the greatest challenges Mike May faces after he regained his sight?
    • We will watch a short (5 minute) video clip on a gentlemen who lost is sight, but gained part of it back in a stem cell transplant.
    • After we view the video, you will be expected to answer the question.
  • What were the greatest challenges Mike May faces after he regained his sight?
    • To interpret visual information his brain received.
    • To develop a visual vocabulary.

Notes - Chapter 4 Section 2:  Vision


  • The sense of sight allows us to gather much information.
  • To understand vision, it is important to know how light works and how our eyes function.

Light – Overhead of electromagnetic spectrum

  • Light is electromagnetic energy that is described in wavelengths.
  • Not all light is visible to humans.
  • What humans can see makes up only a small part of the electromagnetic spectrum.
  • The main colors of the spectrum are red, orange, yellow, green, blue, indigo, and violet.
    • Roy G. Biv
    • The wavelength of light determines the color you see.
      • Longest – Red
      • Shortest - Violet

The Eye

  • Pupil:  the opening in the center of the eye that adjusts to allow light to enter.
  • It is the black circle you see in the middle of the pupil
  • The size of the pupil can change.
  • Also think about when it is bright outside and then you come inside where it is darker.
    • In the bright light your pupils are smaller because only a small amount of light is needed.
    • In the dark they become larger to let in as much light in as possible.
  • Pupil size and emotion:
    • Pupils get larger when:
      • we are interested in someone
      • we are afraid
        • “wide-eyed” with fear
  • Lens:  The transparent structure of the eye that focuses light on the retina.
    • It adjust to the distance of objects by changing its thickness.
  • Changes in the lens project a clear mage of the object onto the retina. 
  • Retina:  the light-sensitive inner surface of the eye.
    • It contains rods, cones, and neurons that process visual stimuli.
  • Photoreceptors:  neurons that respond to light.
    • Once the light hits the photoreceptors, a nerve caries the visual input to the brain.
    • In the brain, the information is relayed to the visual area of the occipital lobe.
    • There are two different kinds of photoreceptors:
      • Rods  - Allow us to see black and white
        • Sensitive to the brightness of light
      • Cones – Provide color vision
  • Blind spot:  that part of the retina that contains no photoreceptors.
  • Dark Adaptation:  if you enter someplace dark your eyes will adjust to lower lighting.
    • your ability to see in low light continues to improve for 45 minutes.
  • Light Adaptation:  if someone turns on the lights in dark room your eyes will adjust.
    • It often seems to “hurt”, but only takes a minute or two to adapt.
    • Adaptation to bright light happens much more quickly than adaptation to the dark.
  • Visual activity:  sharpness of vision.
    • It is determined by the ability to see details in normal light.
    • They often use a Snellen vision Chart
    • 20/100 vision = from a distance of 100 feet away you could see from no more than 20 feet away.
      • This would indicate nearsighted – you need to be close to an object to make out its details.
      • Farsighted- the object needs to be further away to see it clearly.
        • Many older people are farsighted because as people reach their middle age, lenses become more brittle making it difficult to focus.

Color Vision

  • Complementary:  the colors across from each other on the color circle.
    • If complimentary colors of light are mixed the result is the color gray

Fun Fact:  Although you may not be aware of it, the images you see on a television screen actually consists of thousands of very small dots, called pixels.  Each dot is blue, green, or red (the colors are cones are sensitive to).  There are no yellow, purple, or even black or white dots in the television images.  These and other colors are crated through various combinations of blue, green, and red dots.

  • Afterimage:  the visual sensation that occurs after the original stimulus has been removed. (The complimentary color)

Color blindness:  People who do not have normal color vision are said to be color blind

  • Causes some individuals to not distinguish color due to absence of, or malfunction in the cones.
  • Those who are totally color blind see the world in black and white.
    • Total color blindness is rare
  • Partial color blindness is much more common, where individuals are color blind in some areas, but not others.



EXIT TICKET :  Imagine you become completely color blind.  How might your life be different then the way it is now?  How would you have to adjust?  What occupations or hobbies might become difficult for you?

Wednesday October 19

  • Today’s Goal:  The Ear
  • Learning Targets:
    • I can describe how the ear perceives sound.
  • Bell Work: How do you think your ear perceives sound?

Chapter 4 Section 3:  Hearing

  • Sound travels through the air in waves.
  • It is caused by changes in air pressure that result from vibration.
  • Anything that makes a sound causes vibrations called a cycle or sound wave.
  • Every sound has its own pitch and loudness.

Pitch: How high or low a sound is.

  • It depends on the frequency (number of cycles) per second.
    • The more cycles per second, the higher the pitch of the sound.


Loudness: determined by the height, or amplitude, of a sound wave.

  • The higher the amplitude of the wave the louder the sound.
  • Measured in decibels (dB)
    • Zero dB is about as loud as the ticking of a watch 20 feet away.

The Ear

  • The instrument for sensing sound around us
    • Shaped to capture sound waves, vibrate them, and transmit the sound to the brain.
  • Our ear has three parts:
    • Outer ear
    • Middle ear
    • Inner ear.
  • Outer ear
    • Outside part
    • What we think of as the ear.
  • The eardrum is the gateway to the middle ear.
    • It is a thin membrane that vibrates when sound strikes it.
    • As it vibrates it transmits the sound to three small bones in the middle ear which vibrate and transmit sound to the inner ear.
  • Middle ear
    • Bones of the middle ear:
      • Hammer
      • Anvil
      • Stirrup
        • The stirrup is the smallest bone in the human body.
  • Inner ear
    • Consists of the cochlea (Greek for snail)
    • Cochlea:  the fluid-filled structure of the inner ear that transmits sound impulses to the auditory nerve.
      • The movement generates neural impulses that are transmitted to the brain via the auditory nerve.
    • Auditory Nerve:  the cranial nerve that caries sound from the cochlea of the inner ear to the brain.
  • How does the ear transmit sound to the brain?
  • 1. Sound waves strike the eardrum, which transmits vibrations to the middle ear.
  • 2. These vibrations are transferred to the cochlea, which is filled with fluid.
  • 3. Neurons detect vibrations and relay this information to the brain via the auditory nerve.

Locating sounds – Balancing the stereo

  • Balancing a stereo is similar to locating sounds.
  • Example:  If a sound seems louder to our right, you think it is coming from the right.
    • Sound from the right side is reaching the right ear first.

What if the sound comes from in front of you, behind you, or above?

  • All sounds are equally loud and distant from each ear.
  • What do you do?
    • Usually just turn your head a little to determine in which ear the sound increases.
    • You also use visual and other clues in locating the source of sounds.


  • About 2 million Americans are deaf.
  • It can be inherited, or caused by disease, injury, or old age.

Conductive deafness

  • Conductive deafness: hearing loss caused by damage to the middle ear, thus interfering with the transmission of sound waves to the cochlea.
  • Since the middle part of the ear amplifies sounds, damage to it causes people not to be able to hear sounds that are not loud enough.
  • People with conductive deafness usually have hearing aids which amplify the sounds the middle ear cannot.

Sensorineural deafness

  • Senorineural deafness:  deafness that results from damage to the auditory nerve.
  • People with this kind of deafness cannot perceive sounds of certain frequencies.
  • It is usually caused by damage to the inner ear.
    • Usually neurons in the cochlea are destroyed.

What is that ringing?

  • Have you ever attended a concert and left with a ringing sensation in your ears?
    • This may have meant that neurons had been destroyed in your ears.

Deafness in the world today

  • In recent years, people who are deaf have been able to come more into the mainstream of sensory experiences as a result of their own efforts, the efforts of others and new technology.
  • Interpreters often translate things into American Sign Language.
  • TV shows are closed captioned
  • Scientists are trying to find new ways to counteract damage inside the ear.

Exit Ticket:

  • How does the ear transmit sound to the brain?
    • Sound waves strike the eardrum, which transmits vibrations to the middle ear.
    • These vibrations are transferred to the cochlea, which is filled with fluid.
    • Neurons detect vibrations and relay this information to the brain via the auditory nerve.








Thursday October 20

  • Today’s Goal:  Other Sense
  • Learning Targets:  I can identify the chemical, skin, and body senses.
  • Bell Work: Page 90 – Case Study
    • Read Helen Keller’s Story
    • Answer the 2 Thinking Critically Questions in your Journal.
  • Case Study:  Helen Keller
    • 1. How do people compensate for lost senses?
      1. They learn to use the senses they have to compensate for lost senses.
    • 2. What methods did Helen Keller use to communicate with others?
      1. She used sign language done into the hand.
      2. She listened by putting her fingers on a speaker’s nose, lips, and larynx.
      3. She spoke by felling vibrations in the larynx. 

Chapter 4 Section 4:  Other Senses

  • Other senses include:  smell, taste, and the skin and body senses.
    • Smell and tastes are called chemical senses where we sense molecules of substances.
    • The skin detects touch through pressure, temperature, and pain.
    • Body senses alert us to our posture and movement.


  • People do not have as strong of a sense of smell as many animals.
    • Dogs use seven times as much of the cerebral cortex for smell as people do.
  • Without smell we could not taste.
    • For example:  without the sense of smell an apple and an onion would taste very much alike. (Imagine biting into an onion like you would an apple.  YUCK!)
  • Odors of substances are detected by receptor neurons high in each nostril.
    • Receptor neurons react when molecules of the substance in the form of gas come into contact with them.
    • They send information about odors to the brain via the olfactory nerve.
      1. Olfactory Nerve:  The nerve that transmits information about odors from olfactory receptors to the brain.
  • Our sense of smell adapts quickly
    • We adapt rapidly to annoying odors.
    • One odor can also be masked by another.
      1. This is how air fresheners work.


  • Most researchers agree on at least four basic taste qualities – sweet, sour, salty, and bitter.
    • Some argue a 5th called “umami” (Japanese for “meaty” or “savory”)
  • The flavor of food is more complex then taste alone.
    • Flavor depends on odor, texture, temperature, and taste.
  • Taste is sensed through receptor neurons located on taste buds on the tongue.
    • Sensitivities to different tastes can be inherited.
  • Killing taste cells
    • By eating hot foods and scraping your tongue you regularly kill off many taste cells.
    • Thankfully, tastes cells reproduce rapidly enough to renew themselves in a week making the taste system one of the most resilient of all the body’s sensory systems.

The Skin Senses

  • What we normally refer to as “touch”
  • Psychologists call it a skin sense because it is a combination of pressure, temperature, and pain.



  • The sense of touch is important
    • Studies have shown premature infants grow more quickly and stay healthier if they are touched
    • Studies have shown that older people seem to do better if they have a dog or cat to pet.
  • Pressure
    • Your body is covered with hairs.
    • Sensory receptors located in the roots of hair cells fire where the skin is touched.
    • Other structures beneath the skin are also sensitive to pressure.
    • Different parts of the body are more sensitive to pressure than others.
      1. Example:  The fingers, lips, nose, and cheeks are more sensitive then the shoulders, things, and calves.
  • Temperature
    • Sensations of temperature are relative:
      1. When you body is a normal 98.6°F  you might percieve another person’s sking as being warm, but when you are feverish, the other person’s skin might seem cool..
  • The receptors for temperature are neurons just below the skin.
    • When skin temperature increses because you touch something warm, receptors for warmth fire.
    • Decreases in skin temperature cause cold receptors to fire.


  • We adapt to differences in temperature.
    • When you jump into a swimming pool the water may seem cold, but it usually starts to feels warmers as your body adjusts to it.
  • Pain
    • Common types of pain:
      1. Headaches, backaches, toothaches
    • Pain caused by serious health problems:
      1. Arthritis, cancer, or wounds
  • We adapt to pain
    • It motivates us to do something to stop it.
  • Not all areas of the body are equally sensitive to pain.
    • The more pain receptors located in a particular area of our skin, the more sensitive that area is.
  • Once a person gets hurt everything happens quickly
    • 1. The pain message is sent from the point of contact to the spinal cord
    • 2. From the spinal cord it travels to the thalamus in the brain.
    • 3. It is then projected to the cerebral cortex where the person registers the location and severity of the pain.
  • Prostaglandins help the body transmit pain messages to the brain.
    • Aspirin and Ibuprofen are common pain-fighting drugs that work by curbing production of prostaglandins.
  • Gate theory
    • Gate Theorythe suggestion that only a certain amount of information can be processes by the nervous system at a given time.
    • Simple remedies like rubbing or scratching an injured area may help relieve the pain.
      1. Rubbing or scratching transmits sensations to the brain that compete with pain messages for attention, thus the pain message cannot reach the brain.
  • Phantom limbs
    • Many people experience pain in limbs that are no longer there.
    • In such cases, there is no current tissue damage, but the pain is real.
    • The pain appears to involve activation of nerves in the stump of the missing limb, along with activation of neural circuits that have memories connected with the limb.

Body Senses

  • People are rarely aware of body senses, but they are important in keeping us upright, and helping us do things like climb stairs and eat food.

The Vestibular Sense

  • Vestibular Sense:  the sense that provides information about the position of our body.
  • Sensory organs located in our ears monitor our motion and position in relation to gravity.
  • It helps you to keep you balance, tells you whether you are upside down or not, lets you know if you are falling, and if you body is changing speeds.


  • Kinesthesis:  the sense that provides information about the position and movement of individual body parts.
  • Sensory information is fed to the brain from sensory organs in the joints, tendons, and muscles.

Friday October 21

  • Today’s Goal:  Reading like a psychologist / Review Sections 1 – 4 of Chapter 4
  • Learning Targets:
    • I can distinguish between sensation and perception and explain how they contribute to an understanding of our environment.
    • Explain how the eye works to enable vision.
    • Describe how the ear perceives sound.
    • Identify the chemical, skin, and body senses.
  • Bell Work: Read through the first 2 paragraphs on your own.

Work day

  • Catch up on any notes we are behind on.
  • Practice reading like a psychologist.
  • Chapter 4 Review (skip section 5 questions)

Monday October 24

  • Materials Needed: Projector and Computer
  • Today’s Goal: Perception
  • Learning Targets: I can summarize the laws of sensory perception.
  • Bell Work: First answer today’s journal question. Optical illusions may look like clever tricks, but they can show a lot about how the brain works. In your journal record what do you see in the picture below? 
  • Second take out assignment from Friday so you can hand it in.
    • (If you were absent get one from the absent binder)
  • Give students a chance to work on

Notes Chapter 4 Section 5:  Perception

  • In general:
    • Every day our senses pick up countless stimuli.
    • Imagine the confusion if we did not find ways to organize all that information.
    • REMEMBER:  Perception is the way in which we organize or make sense of what our senses bring in.
  • Rules of Perceptual Organization:  The Gestalt psychologists applied the principle that “the whole is more than the sum of its parts.”  Using this principle, they noted many different ways in which people make sense of sensory information. They are called the rules of perceptual organization:
    • Perceptual rules of organization:  closure, figure-ground perception, proximity, similarity, continuity, and common fate.
    • Closure
      • Closure:  The tendency to perceive a complete or whole figure even when there are gaps in what your senses tell you.
        • Filling in the blanks.
    • Figure-Ground Perception
      • Figure-Ground Perception:  The perception of figures against a background
      • We experience this every day, but it is what we perceive as the figure and what we perceive as the background that influence our perception.


  • Other Rules of Organization:  Proximity, Similarity, Continuity, Common Fate


  • What did you see?


  • 4 lines
  • 2 pairs of lines
  • If you said 2 pairs of lines you were influenced by proximity
  • Proximity:  The perceptual tendency to group together visual and auditory events that are near each other.
  • Demo:   Proximity
    • Tap out the following rhythm:  2 beats Pause, 2 beats Pause, 2 beats Pause.
      • Ask students to describe the pattern they heard.
        • Most will say three sets of two beats.
        • Point out they could have said 6 beats, but the proximity of two beats to each other in each set (with the pause) made the students mentally organize them into sets.





  • What did you see?
    • 6 by 6 grid
    • 3 columns of X’s and 3 columns of O’s
  • If you saw three columns you were influenced by similarity


  • Similarity:  The perceptual tendency to group together elements that seem alike.
  • What did you see?
    • A series of half circles?
    • A wavy line and a straight line
  • If you saw the wavy and straight line you were organizing your perceptions according to the law of continuity.
    • Continuity:   The perceptual tendency to group stimuli into continuous patterns.
      • People generally like to see smooth continuous patterns (like lines and waves) rather then disrupted ones.
    • Common fate:  The tendency to perceive objects that are moving together as belonging together.
    • A group of people running together in the same direction appear to have the same purpose.  You assume they are all part of a group that is running to the same place – that they have a common fate.
  • Stroboscopic Motion
    • Stroboscopic motion:  the illusion of movement is produced by showing the rapid progression of images or objects that are not moving at all.
      • Example:  A flip book
      • Example:  Movies
        • Movies consist of stationary images shown 16 – 22 pictures  a second.
          • Each frame is slightly different from the previous one.
            • When thy are shown in rapid succession it creates an illusion of movement due to the law of continuity where humans prefer to see things as one continuous image. (Perception fills in the gap)
  • Depth Perception: In psychology “depth” means “distance away”
    • Monocular Cues for Depth
      • Monocular Cues:  cues for distance that may be available to either eye alone.
      • Can be used to create illusions of depth/3-D on flat surfaces
      • It can make objects appear more distant from view than others
      • Monocular cues cause certain objects to appear more distant from the viewer then others.
        • These cues include perspective, clearness, overlapping, shadow, and texture gradient.
          • Clearness – nearby objects are clearer/have more details as opposed to far away objects which seem less clear/detailed.
          • Overlapping – perceiving one object as being in front of the other.  Nearby objects block the view of objects that are further away.
          • Shadows – tell us where things are in relation to the source of light.
          • Texture gradient – texture that is far away appears denser then texture that is closer.
      • Motion parallax
        • You may notice that when you are driving that some objects seem to move quickly past, some stand still, and some seem to move with you.
          • Distant objects (mountains, the moon, stars) appear to move with you.
          • Objects at an intermediate distance seem to stand still.
          • Nearby objects like trees and road signs go by quite rapidly.
        • Motion parallax allows us to realize that objects that appear to move with us are at a greater distance then objects that pass quickly.
    • Binocular Cues for Depth
      • Binocular Cues:  Visual cues for depth that require the use of both eyes.
        • There are two:  Retinal Disparity and Convergence
      • Demo:
        • Hold a finger at arm’s length. 
        • Now slowly bring the finger closer until it almost touches your nose.
        • If you keep your eyes relaxed you will see two fingers.
        • An image of each finger will be projected on the retina of each eye.
        • Each image will be slightly different because the finger will be seen at different angles.
        • This difference is retinal disparity
      • Retinal Disparity: A binocular cue for perceiving depth based on the difference between the two images of an object that the retina receives as the object moves closer or farther away.
        • The closer your finger comes the farther apart the “two fingers” appear to be.
          • This gives us a cue to depth.
      • Convergence:  The closer we feel our eyes moving towards each other, the nearer the object is.
  • Growing friends?
    • Imagine you are headed down to lunch and you see your friends waiting at your usual table some distance away.  As you run over to them, they get closer and look larger because they are taking up more space you retina. Why do you think your friends are not growing in inches?  This would certainly be the case judging from sensory input alone.
      • The reason is experience.
  • Perceptual Constancies:  Experience allows us to override inconsistent sensory inputs.
    • Size Constancy:  The tendency to perceive an object as being of one size no matter how far way the object is.
      • Example:  When we are in an airplane or in a tall building people below look like “ants” but we know they remain people even if the details of their forms are lost in the distance.
    • Color Constancy:  The tendency to perceive objects as keeping their color even though different light might change the appearance of their color.
      • Example:  If your PJs are blue and you can’t see them because it is dark, you still know they are blue.
    • Brightness Constancy:  the tendency to perceive an object as being equally bright even when the intensity of the light around it changes.
      • Which gray square looks brighter?
        • Most people say the one in the black frame looks brighter because we judge brightness of an object by the brightness of other objects around it.
    • Shape Constancy:  the knowledge that an item has only one shape no matter what angle you view it from.
    • A door appears to be a rectangle only when you view it straight on.  When you move to the side or open it, the left or right edge comes closer and appears to be larger, changing the retinal image of the door to a trapezoid. Yet, because of shape consistency, you continue to think of doors as rectangular.
  • Visual Illusions – Are our eyes playing tricks on us?
    • Illusions are your brains use of perceptual constancies.  Your brain can trick your eye.
    • Muller-Lyer Illusion:  Which line is longer?


  • Even though the one on the left appears longer, they are actually both the same length!
    • Our eye has been tricked by experience.
      • In our culture we are used to living in rooms and buildings.
    • The line on the right reminds us of how a far corner of a room looks, while the line on the left reminds us of how a far corner of a room looks, while the left line reminds us of the outside near corner of a building.
  • Ponzo illusion – which line seems longer?

  • Most people perceive the top line as being longer due to the law of consistency.
    • The converging lines seem to be going off into the distance so we assume from experience that the horizontal line at the top is further down the track and farther away.