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Sensation and Perception. Chapter 4 page 78. The 5 senses ( sensory organs). Sight (eyes) Hearing (ears) Smell (nose) Touch (skin) Taste (tongue). Your 3 senses . Select 3 things from each sense that you could not live without. Select 1 from each that you could live without .

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sensation and perception

Sensation and Perception

Chapter 4 page 78

the 5 senses sensory organs
The 5 senses (sensory organs)

Sight (eyes)

Hearing (ears)

Smell (nose)

Touch (skin)

Taste (tongue)

your 3 senses
Your 3 senses

Select 3 things from each sense that you could not live without.

Select 1 from each that you could live without.






our sensational senses
Our Sensational Senses
  • Defining sensation and perception
  • The riddle of separate senses
  • Measuring the senses
  • Sensory adaptation
  • Sensory overload
defining sensation and perception
Defining Sensation and Perception
  • Sensation
    • The detection of physical energy emitted or reflected by physical objects.
    • It occurs when energy in the external environment or the body stimulates receptors in the sense organs.
  • Perception
    • The process by which the brain organizes and interprets sensory information.

Ambiguous Figure

  • Colored surface can be either the outside front surface or the inside back surface
    • Cannot simultaneously be both
  • Brain can interpret the ambiguous cues two different ways
the riddle of separate sensations
The Riddle of Separate Sensations
  • Sense receptors
    • Specialized cells that convert physical energy in the environment or the body to electrical energy that can be transmitted as nerve impulses to the brain.
measuring senses
Measuring Senses
  • Absolute threshold
  • Difference threshold
absolute threshold
Absolute Threshold
  • The smallest quantity of physical energy that can be reliably detected by an observer.
absolute sensory thresholds
Absolute Sensory Thresholds
  • Vision:
    • A single candle flame from 30 miles on a dark, clear night
  • Hearing:
    • The tick of a watch from 20 feet in total quiet
  • Smell:
    • 1 drop of perfume in a 6-room apartment
  • Touch:
    • The wing of a bee on your cheek, dropped from 1 cm
  • Taste:
    • 1 tsp. Sugar in 2 gal. water
difference threshold
Difference Threshold
  • The smallest difference in stimulation that can be reliably detected by an observer when two stimuli are compared;
sensory adaptation and deprivation
Sensory Adaptation and Deprivation
  • Adaptation
    • The reduction or disappearance of sensory responsiveness when stimulation is unchanging or repetitious.
    • Prevents us from having to continuously respond to unimportant information.
  • Deprivation
    • The absence of normal levels of sensory stimulation.
sensory overload
Sensory Overload
  • Overstimulation of the senses.
  • Can use selective attention to reduce sensory overload.
    • Selective attention
      • The focusing of attention on selected aspects of the environment and the blocking out of others.
  • What we see
  • An eye on the world
  • Constructing the visual world
what we see
What We See
  • Hue
    • Visual experience specified by colour names and related to the wavelength of light.
  • Brightness
    • Lightness and luminance; the visual experience related to the amount of light emitted from or reflected by an object.
  • Saturation
    • Vividness or purity of colour; the visual experience related to the complexity of light waves.
what we see1
What We See
  • Hue
  • Brightness
  • Saturation
an eye on the world
An Eye on the World
  • Cornea
    • Protects eye and bends light toward lens.
  • Lens
    • Focuses on objects by changing shape.
  • Iris
    • Controls amount of light that gets into eye.
  • Pupil
    • Widens or dilates to let in more light.
an eye on the world1
An Eye on the World
  • Retina
    • Neural tissue lining the back of the eyeball’s interior, which contains the receptors for vision.
  • Rods
    • Visual receptors that respond to dim light.
  • Cones
    • Visual receptors involved in colour vision. Most humans have 3 types of cones.
constructing the visual world
Constructing the Visual World
  • Form perception
  • Depth and distance perception
  • Visual constancies: When seeing is believing
  • Visual illusions: When seeing is misleading
form perception
Form Perception
  • Gestalt principles describe the brain’s organization of sensory building blocks into meaningful units and patterns.
figure and ground
Figure and Ground
  • Proximity
    • Seeing 3 pair of lines in A.
  • Similarity
    • Seeing columns of orange and red dots in B.
  • Continuity
    • Seeing lines that connect 1 to 2 and 3 to 4 in C.
  • Closure
    • Seeing a horse in D.
depth and distance perception
Depth and Distance Perception
  • Binocular Cues:
    • Visual cues to depth or distance that require the use of both eyes.
    • Convergence: Turning inward of the eyes, which occurs when they focus on a nearby object.
    • Retinal Disparity: The slight difference in lateral separation between two objects as seen by the left eye and the right eye.
depth and distance perception1
Depth and Distance Perception
  • Monocular Cues:
    • Visual cues to depth or distance that can be used by one eye alone.
the ames room
The Ames Room
  • A specially-built room that makes people seem to change size as they move around in it
  • The room is not a rectangle, as viewers assume it is
  • A single peephole prevents using binocular depth cues
visual constancies
Visual Constancies
  • The accurate perception of objects as stable or unchanged despite changes in the sensory patterns they produce.
    • Shape constancy
    • Location constancy
    • Size constancy
    • Brightness constancy
    • Colour constancy
shape constancy
Shape Constancy
  • Even though these images cast shadows of different shapes, we still see the quarter as round
visual illusions
Visual Illusions
  • Illusions are valuable in understanding perception because they are systematic errors.
    • Illusions provide hints about perceptual strategies.
  • In the Muller-Lyer illusion (above) we tend to perceive the line on the right as slightly longer than the one on the left.
the ponzo illusion
The Ponzo Illusion
  • Linear perspective provides context
  • Side lines seem to converge
  • Top line seems farther away
    • But the retinal images of the red lines are equal!
fooling the eye
Fooling the Eye
  • The cats in (a) are the same size
  • The diagonal lines in (b) are parallel
  • You can create a “floating fingertip frankfurter” by holding hands as shown, 5-10” in front of face.
section 3

Section 3


  • What we hear
  • An ear on the world
  • Constructing the auditory world
what we hear
What We Hear
  • Loudness
    • The dimension of auditory experience related to the intensity of a pressure wave.
  • Pitch
    • The dimension of auditory experience related to the frequency of a pressure wave.
  • Timbre (pronounced “TAM-bur”)
    • The distinguishing quality of sound; the dimension of auditory experience related to the complexity of the pressure wave.
auditory localization
Auditory Localization
  • Sounds from different directions are not identical as they arrive at left and right ears
    • Loudness
    • Timing
    • Phase
  • The brain calculates a sound’s location by using these differences.
section 4

Section 4

Other senses

other senses
Other Senses
  • Taste: savory sensations
  • Smell: The sense of scents
  • Senses of the skin
  • The environment within
the taste buds
The Taste Buds
  • Bitter
  • Sour
  • Sweet
  • Salty
taste savoury sensations
Taste: Savoury Sensations
  • Papillae
    • Knoblike elevations on the tongue, containing the taste buds (Singular: papilla).
  • Taste buds
    • Nests of taste-receptor cells.
taste buds
Taste Buds
  • Photograph of tongue surface (top), magnified 75 times.
  • 10,000 taste buds line the tongue and mouth.
    • Taste receptors are down inside the “bud”
  • Children have more taste buds than adults.
four tastes
Four Tastes
  • Four basic tastes
    • Salty, sour, bitter and sweet.
  • Different people have different tastes based on:
    • Genetics
    • Culture
    • Learning
    • Food attractiveness
smell the sense of scents
Smell: The Sense of Scents
  • Airborne chemical molecules enter the nose and circulate through the nasal cavity.
    • Vapors can also enter through the mouth and pass into nasal cavity.
  • Receptors on the roof of the nasal cavity detect these molecules.
the environment within
The Environment Within
  • Kinesthesis
    • The sense of body position and movement of body parts; also called kinesthesia.
  • Equilibrium
    • The sense of balance.
  • Semicircular Canals
    • Sense organs in the inner ear, which contribute to equilibrium by responding to rotation of the head.
perceptual powers origins and influences
Perceptual Powers: Origins and Influences
  • Inborn abilities
  • Critical periods
  • Psychological and cultural Influences on perception
the visual cliff
The Visual Cliff
  • Glass surface, with checkerboard underneath at different heights
    • Visual illusion of a cliff
    • Baby can’t fall
  • Mom stands across the gap
  • Babies show increased attention over deep side at age 2 months, but aren’t afraid until about the age they can crawl (Gibson & Walk, 1960)
critical periods
Critical Periods
  • If infants miss out on experiences during a crucial period of time, perception will be impaired.
  • When adults who have been blind since birth have vision restored, they may not see well
  • Other senses such has hearing may be influenced similarly.
psychological and cultural influences on perception
Psychological and Cultural Influences on Perception
  • We are more likely to perceive something when we need it.
  • What we believe can affect what we perceive.
  • Emotions, such as fear, can influence perceptions of sensory information.
  • Expectations based on our previous experiences influence how we perceive the world.
    • Perceptual Set
      • A habitual way of perceiving, based on expectations.
  • All are influenced by our culture.
perceptual set
Perceptual Set
  • What you see in the centre figures depends on the order in which you look at the figures:
    • If you scan from the left, see an old woman
    • If you scan from the right, see a woman’s figure
context effects
Context Effects
  • The same physical stimulus can be interpreted differently
  • We use other cues in the situation to resolve ambiguities
  • Is this the letter B or the number 13?
puzzles of perception
Puzzles of Perception
  • Subliminal Perception
subliminal perception
Subliminal Perception
  • Perceiving without awareness
    • visual stimuli can affect your behaviour even when you are unaware that you saw it
    • nonconscious processing also occurs in memory, thinking, and decision making
    • these effects are often small, however, and difficult to demonstrate and work best with simple stimuli
subliminal perception1
Subliminal Perception
  • Perception versus Persuasion
    • there is no empirical research to support popular notions that subliminal persuasion has any effect on a person’s behaviour
    • persuasion works best when messages, in the form of advertising or self-help tapes, are presented above-threshold, or at a supraliminal level