PSYCHOLOGY Vision

Say the color when you see it GREEN BLUE ORANGE RED

Try it Turn your eyes to the left Close them Gently rub the right side of your eyelid with your finger tip What happens? patch of light on left moves as your finger does Why light? Why the the left?

Try it explanation Cell receptors in your eye are sensitive to pressure Your brain interprets it as light It interprets it as coming from the left because you activated the right side of the retina

Vision Transduction conversion of one form of energy to another in sensation, transforming of stimulus energies into neural impulses

Vision Wavelength determines hue (color) Intensity of color determined by amplitude (height) of wave

Vision Wavelength Hue Intensity the distance from the peak of one wave to the peak of the next Hue dimension of color determined by wavelength of light Intensity amount of energy in a wave determined by amplitude brightness loudness

Vision- Physical Properties of Waves Short wavelength=high frequency (bluish colors, high-pitched sounds) Long wavelength=low frequency (reddish colors, low-pitched sounds) Great amplitude (bright colors, loud sounds) Small amplitude (dull colors, soft sounds)

The spectrum of electromagnetic energy

Vision

The eye my Corny Pupil named Iris Lens me Rods & Cones - mnemonic

Vision - light travels…. Cornea - protects eye/bends light Pupil which is regulated by the Iris Dilated - interested, you like Iris scanning for ID Lens accommodates Retina has the receptor cells- rods & cones

Retina’s Reaction to Light- Cell Receptors Rods peripheral retina receptors detect black, white and gray for peripheral or twilight conditions Cones receptors near center of retina fine detail and color vision for daylight or well-lit conditions

Vision- Receptors Receptors in the Human Eye Cones Rods Number Location in retina Sensitivity in dim light Color sensitive? Yes Low Center 6 million No High Periphery 120 million

Retina’s Reaction to Light From the rods & cones chemical signals other cells are activated: (Bipolar gang of lions) Bipolar cells Ganglion cells Network of ganglion cells converge to form the optic nerve Optic nerve- nerve that carries neural impulses from the eye to the brain (thalamus to VISUAL CORTEX IN THE OCCIPITAL LOBE)

Pathways from the Eyes to the Visual Cortex

Vision problems Nearsightedness- Farsightedness- Eyeball is too long Eyeball is too short

Vision p.199 Farsighted Nearsighted Normal Vision Vision Vision

Acuity Nearsightedness- condition in which nearby objects are seen more clearly than distant objects because distant objects focus in front of retina Eyeball is too long Farsightedness- condition in which faraway objects are seen more clearly than near objects because the image of near objects is focused behind retina Eyeball is too short

Vision Pupil- adjustable opening in the center of the eye Iris- a ring of muscle that forms the colored portion of the eye around the pupil and controls the size of the pupil opening

Vision Lens- transparent structure behind pupil that changes shape to focus images on the retina Accommodation- the process by which the eye’s lens changes shape to help focus near or far objects on the retina

Vision Retina- the light-sensitive inner surface of the eye, containing receptor rods and cones plus layers of neurons that begin the processing of visual information Your brain flips objects around

Vision Acuity- the sharpness of vision Can be affected by small distortions in the shape of the eye Glasses, contacts, LASIK surgery

Vision Blind Spot- point at which the optic nerve leaves the eye, creating a “blind spot” because there are no receptor cells located there p. 200 (find yours) Fovea- central point in the retina, around which the eye’s cones cluster

Visual Information Processing p. 202 Feature Detectors (Hubel & Wiesel) nerve cells in the brain that respond to specific features Edges, lines Shape, angle movement Stimulus Cell’s responses

Feature detection Perceptions arise from interaction of many neuron systems Occipital lobe with the visual cortex transmits info to other lobes Brain areas light up on fMRI scans, EEG reveal integration of activity P. 202 Areas are specialized to do certain tasks

How the Brain Perceives p. 203 Bottom up & top down processing with perception Stare at the cube, constant stimulation, change Brain activity combines sensory input w/ assumptions and expectations

Illusory Contours

Vision Case Studies p. 203-204 Computers follow a step by step process but your brain does several things at once What is this called?

Visual Information Processing p. 204-205 Parallel Processing simultaneous processing of several aspects of a problem simultaneously

Parallel processing Your brain is awesome!!!!! Read Sperry’s reflection p. 205

Questions If now one sees the tomato is it red? NO p. 206 Color resides in the theater of our brains.

Color Vision Color blind 1 in 50 Usually a male - genetic, sex-linked trait Theories of color Hermann von Helmholtz Thomas Young 3 primary colors, 3 types of cell receptors

Visual Information Processing Trichromatic (three color) Theory Young and Helmholtz three different retinal color receptors red green blue

Color-Deficient Vision People who suffer red-green dificiency have trouble perceiving the number within the design

Color Vision Figure 12.16

Visual Information Processing Opponent-Process Theory- opposing retinal processes enable color vision (HERING) “ON” “OFF” red green green red blue yellow yellow blue black white white black

Opponent Process- Afterimage Effect

Visual Information Processing Color Constancy Perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object