Sensation vs. Perception
 Sensation
 Energy  receptor cell  transduction
 Perception
 Interpretation of sensation

Sensory Thresholds
 Absolute threshold
 Difference threshold
 Just noticeable difference

Weber’s law
 How sensitive are you?
 Sensory adaptation

Visual System
 Psychologists have studied vision more than any other sense

The Visual System
 Light enters the eye through the cornea

The Visual System
 Light enters the eye through the cornea
 Neural impulses are created in the retina by receptor cells
 rods and cones

Cells in the Retina

Trichromatic Theory

Trichromatic Theory
 There are three types of cones:
 red, green, and blue
 Perceived colors are result from differing amount of light absorbed by the three types of cones .

Opponent-Process Theory
 Color-sensitive ganglion cells are arranged in opposing cells
 Red-green, yellow-blue, black-white
 Activation of one cone inhibits another
 May explain some kinds of afterimages

Gestalt Psychology
 Gestalt psychologists investigated the principles that guide how we create a coherent perceptual experience
 Figure-Ground Distinction

Proximity

Proximity – Take 1

Proximity – Take 2

Similarity

Continuation

Closure

Good Figure

Common Fate

Depth Perception
 Binocular Cues
 Retinal disparity

Depth Perception
 Binocular Cues

Depth Perception
 Monocular Cues
 Object size/Size constancy

Depth Perception
 Linear Perspective

Depth Perception
 Relative size and linear perspective

Depth Perception
 Detail
 Interposition

Depth Perception
 Texture Gradient

 Shadows
Depth Perception

Depth Perception
 Aerial
Perspective

Depth Perception
 Motion Parallax
 Demonstration

Hearing

Sound…
 How do we hear?

Hearing Loss
 Conductive Hearing Loss
 Nerve Deafness

Pitch Perception
 Place Theory
 Frequency Theory
 Volley principal
 Auditory Perception
 Localizing Sound

Smell

Taste
 Receptor cells are in buds on tip, sides, and back of the tongue.

Kinesthetic and Vestibular Senses
 Kinesthetic sense
 Muscle movement, changes in posture, and strain on muscles and joints
 Stretch receptors and golgi tendon organs
 Vestibular sense
 Equilibrium & body position in space
 Semicircular canals of inner ear & vestibular sacs

The Skin Senses
 Receptors in the skin
 Touch, Pressure, Temperature,
Pain
 Information goes to brain through two routes
 Through medulla and thalamus to sensory cortex, or
 From thalamus to reticular formation.

Pain
 Gate-control theory
 A gate in spinal cord permits, prevents pain signals from passing
 Other impulses can overwhelm
 Perception can influence pain