PSYCHOLOGY

Vision

Say the color when you see it

GREENBLUEORANGERED

Try it

Turn your eyes to the leftClose themGently rub the right side of your eyelid

with your finger tipWhat 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 lightIt 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

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 lightPupil which is regulated by the Iris

Dilated - interested, you like Iris scanning for ID

Lens accommodatesRetina 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- Eyeball is too long

Farsightedness- 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. 202Areas are specialized to do certain tasks

How the Brain Perceives p. 203Bottom 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 50Usually a male - genetic, sex-linked trait

Theories of colorHermann von HelmholtzThomas Young3 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 greengreen red blue yellow yellow blue black whitewhite 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