1. Wadsworth, a division of Thomson Learning

2. Important Definitions
Sensation-stimulation of the sensory systems
Perception-interpretation of the sensory information
Thresholds
Absolute-minimum amount of a stimulus that is detectable by an organism
Difference-minimum amount of a change in stimulus that is detectable by an organism
Weber’s Law-the size of the difference necessary for the organism to notice it is proportional to the size of the initial stimulus
Adaptation-gradual decline in sensitivity to prolonged stimulation
Subliminal-a stimulus below conscious awareness
Supraliminal-a stimulus above conscious awareness

3. Vision-The Stimulus Light-electromagnetic radiation
Amplitude-brightness
wavelength-color
saturation-richness or purity of the color

5. Vision-The Anatomy Cornea-transparent covering on the front of the eye
Lens-transparent structure that focuses an image on the back of the eye
Pupil-the dark part of the center of the eye that regulates the amount of light that enters the eye
Iris-the colored muscle of the eye that changes the size of the pupil
Retina-neural tissue at the back of the eye that transfers light information into neural signals
Blind Spot-the area of the retina where the optic nerve leaves the back of the eye
Fovea-central point of focus on the back of the eye

7. Vision-Fine Anatomy of the Retina
Receptors
Rods
Provide black/white vision
located in high concentration in the periphery of the retina
nighttime vision with poor acuity
Cones
Provide color vision
located in high concentration around the fovea
daytime vision with high acuity
Bipolar Cells-Second-layer cells in the retina
Ganglion Cells-Third-layer cells in the retina, their axons form the optic nerve.

9. Vision-The Visual Pathway

10. Vision-Theories of Color Vision
Trichromatic Theory-the eye contains three types of cones capable of differential responding to various wavelengths of light
Opponent Process Theory-color perception depends on receptors that make antagonist responses to three pairs of colors

12. Visual Perception Gestalt Principles Proximity Simplicity
Connectedness
Closure
Continuity
Similarity

14. Visual Perception Depth Perception-The Visual Cliff
Binocular Cues-clues about distance based on the differing views of the two eyes
Retinal Disparity-the fact that the right and left eyes see slightly different views of the object
Accommodation-the degree to which the two eyes must converge to focus on the object
Monocular Cues-clues about distance based on the image in either eye
Linear Perspective-parallel lines converge in the distance
Relative Size-if two objects are the same, the larger one is seen as closer
Overlap-the nearer object overlaps the object farther in the distance
Texture Gradient-textures are coarser the closer they are

17. Visual Perception
Perceptual Constancies-the ability to experience a constant perception even when what is reflected on the retina changes
Color-an object will be perceived as the same color even if the color reflected on the retina changes (ex: when an object is placed in the shade)
Size-an object will be perceived as the same size even if the size reflected on the retina changes (ex: a dog running toward you is not seen as growing in size)
Shape-an object will be perceived as the same shape even if the shape reflected on the retina changes (ex: a door opening toward you is still perceived as rectangular)

19. Select Illusions