Sensation and Perception

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Sensation and Perception

• Chapter 3

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Sensation
LO 3.1 Sensation and the central nervous system

• Sensation - the activation of receptors in the
  various sense organs.
• Sensory receptors - specialized forms of neurons.
• Sense organs
• eyes
• ears
• nose
• skin
• taste buds

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Eye Sensory Receptors
Sensory receptor
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Ear Sensory Receptors
Sensory receptors
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Nose Sensory Receptors
Sensory receptor
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Skin Sensory Receptors
Pain
Light touch
Cold
Heat
Strong pressure
Hair movement
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Sensation and Perception

• Stimulus energy
• Heat
• Light

• Sensory receptor
• Eyes
• Nose
• Skin

Neural impulse

• Brain
• Visual
• Olfactory

Sensation
Perception
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Sensory Thresholds
LO 3.1 Sensation and the central nervous system

• Absolute threshold - smallest amount of energy
  needed for a person to consciously detect a
  stimulus (50 of time)
• Just noticeable difference smallest difference
  between two stimuli that is detectable (50 of
  time)
• http//www.google.com/search?hlensourcehpqvan
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Habituation and Sensory Adaptation
LO 3.1 Sensation and the central nervous system

• Habituation - tendency of the brain to stop
  attending to constant, unchanging information.
• Sensory adaptation - tendency of sensory receptor
  cells to become less responsive to a stimulus
  that is unchanging.

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Light
Amplitude
Wavelength
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Psychological Aspects to Light
LO 3.2 What is light

• Brightness - amplitude of the wave higher waves
  brighter lower waves dimmer.
• Color - length of the wave long wavelengths red
  short waves blue
• Saturation - purity of the color people see

Saturation
Color
Brightness
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Structure of the Eye
LO 3.3 How eyes see and see color

• Cornea clear membrane that covers surface of
  eye protects eye and focuses most of light
  coming into eye.
• Pupil hole through which light from the visual
  image enters eye.

Cornea
Pupil
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Structure of the Eye
LO 3.3 How eyes see and see color

• Iris - round muscle can change the size of the
  pupil, letting more or less light into the eye
  helps focus the image.
• Lens suspended by muscles finishes the
  focusing process begun by the cornea.

Lens
Iris
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Retina, Rods, and Cones
LO 3.3 How eyes see and see color

• Photoreceptors that respond to various light
  waves
• Rods receptors responsible for non-color vision
  and sensitivity to dim light.
• Cones receptors responsible for color vision
  and sharpness of vision.

Retina
Cone
Optic nerve
Rod
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Visual Field of left eye
Visual field of right eye
Optic nerve
Optic chasm
Primary visual area
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Color Vision
LO 3.3 How eyes see and see color

• Trichromatic theory - theory of color vision that
  proposes three types of cones red, blue, and
  green.
• Opponent-process theory - theory of color vision
  that proposes four primary colors with cones
  arranged in pairs red and green, blue and yellow

Or
Or
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Color Blindness
LO 3.3 How eyes see and see color

• Monochrome colorblindess - either have no cones
  or have cones that are not working at all.
• Red-green colorblindess - either the red or the
  green cones are not working.

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Sound
LO 3.4 What is sound
Amplitude

• Amplitude volume (how soft or loud a sound is).
• Wavelength frequency or pitch
• Purity timbre (a richness in the tone of the
  sound).
• http//www.youtube.com/watch?v2RkaD9nAv34.

Wavelength
Quieter
Louder
Deeper pitch
Higher pitch
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Structure of the Ear
LO 3.4 What is sound

• Auditory canal - short tunnel that runs from the
  pinna to the eardrum
• Eardrum - thin section of skin that tightly
  covers the opening into the middle part of the
  ear

Eardrum
Auditory canal
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Structure of the Ear

• When sound waves hit the eardrum, it vibrates and
  causes three tiny bones in the middle ear to
  vibrate.
• Hammer
• Anvil
• Stirrup

Hammer
Hammer
Stirrup
Anvil
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Structure of the Ear
LO 3.4 What is sound

• Cochlea - snail-shaped structure of the inner ear
  that is filled with fluid.
• Organ of Corti rests in the basilar membrane
  contains receptor cells for sense of hearing.

Organ of Corti
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Structure of the Ear
http//www.youtube.com/watch?v7a2aoZeZhZ8feature
related http//www.youtube.com/watch?v8wgfowbbTz
0featurerelated Auditory nerve - bundle of
axons from the hair cells in the inner ear
receives neural message from the organ of Corti.
Auditory nerve
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Theories of Pitch
LO 3.4 What is sound

• Pitch - frequency of the sound waves higher
  frequencies are perceived as higher pitches.
• Place theory - states that different pitches are
  experienced by the stimulation of hair cells in
  different locations on the organ of Corti.

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Theories of Pitch
LO 3.4 What is sound

• Frequency theory - states that pitch is related
  to the speed of vibrations in the basilar
  membrane.

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Taste
LO 3.6 Senses of taste and smell

• Taste buds taste receptor cells in mouth
  responsible for sense of taste
• Gustation - the sensation of a taste.
• Five Basic Tastes
• Sweet
• Sour
• Salty
• Bitter
• Brothy

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Taste
LO 3.6 Senses of taste and smell
Bitter
Taste pore
Sour
Receptor cell
Salty
Sweet
Nerve fiber
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Smell
LO 3.6 Senses of taste and smell

• Olfaction (olfactory sense) sense of smell.
• Olfactory bulbs - areas of the brain that receive
  information from the olfactory receptor cells.

Receptor
Olfactory bulb
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Somesthetic Senses
LO 3.7 Touch, pain, motion and balance

• Somesthetic senses - the skin senses, the
  kinesthetic sense, and the vestibular senses.
• Skin senses - the sensations of touch, pressure,
  temperature, and pain.
• Kinesthetic sense - sense of the location of body
  parts in relation to the ground and each other.

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Somesthetic Senses
LO 3.7 Touch, pain, motion and balance

• 3. Vestibular senses - the sensations of
  movement, balance
• Sensory conflict theory in which the information
  from the eyes conflicts with the information from
  the vestibular senses resulting in dizziness.

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Perception and Constancies
LO 3.8 Perception and perceptual constancies

• Perception - the method by which the sensations
  experienced at any given moment are interpreted
  and organized in some meaningful fashion.
• http//www.youtube.com/watch?vL3AgO6H0H98

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Constancy

• Size constancy - the tendency to interpret an
  object as always being the same actual size,
  regardless of its distance.

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Constancy

• Shape constancy - the tendency to interpret the
  shape of an object as being constant, even when
  its shape changes on the retina.

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Constancy

• Brightness constancy the tendency to perceive
  the apparent brightness of an object as the same
  even when the light conditions change.

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Gestalt Principles
LO 3.9 Gestalt principles of perception

• Figureground - the tendency to perceive objects
  as existing on a background.

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Gestalt Principals

• Reversible figures - visual illusions in which
  the figure and ground can be reversed.

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Gestalt Principals
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Gestalt Principles
LO 3.9 Gestalt principles of perception
Similarity
Proximity
Continuity
Closure
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Development of Perception
LO 3.10 Perceiving the world in three dimensions

• Depth perception - the ability to perceive the
  world in three dimensions

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Monocular Cues
LO 3.10 Perceiving the world in three dimensions

• Monocular cues (pictorial depth cues) cues for
  perceiving depth based on one eye only.

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Monocular cues
LO 3.10 Perceiving the world in three dimensions
Linear Perspective
Texture gradient
Relative size
Areal perspective
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Binocular Cues

• Binocular cues - cues for perceiving depth based
  on both eyes.
• Convergence - the rotation of the two eyes to
  focus on a single object, resulting in greater
  convergence for closer objects and lesser
  convergence if objects are distant.

Focal point
Left
Right
Far
Near
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Binocular Cues

• Binocular disparity - the difference in images
  between the two eyes, which is greater for
  objects that are close and smaller for distant
  objects.

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Perceptual Illusions
LO 3.11 Visual illusions
Müller-Lyer illusion
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Perceptual Illusions
LO 3.11 Visual illusions
Moon Illusion
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Perceptual Illusions
LO 3.11 Visual illusions and other factors
influencing perception

• Illusions of Motion
• Stroboscopic motion - seen in motion pictures, in
  which a rapid series of still pictures will
  appear to be in motion.

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Factors that Influence Perception
LO 3.11 Visual illusions and other factors
influencing perception

• Perceptual expectancy- the tendency to perceive
  things a certain way because previous experiences
  or expectations influence those perceptions.