Structure of the Eye, Depth Perception, & Theories of Color Vision

blind spot

the area of the retina were the optic nerve leaves the eye. This are contains no rods or cones.

proximity

group nearby figures together.

similarity

we group figures similar to each other together.

continuity

we perceive smooth continuous patterns rather than discontinuous ones.

closure

we fill in gaps to create a whole complete object.

connectedness

when they are uniform and linked we perceive spots lines or areas as a single unit.

Figure-Ground

the organization of the visual field into objects (figures) that stand out from their surroundings (ground).

Opponent Process Theory

developed by Ewald Hering Opposing retinal processes (red-green yellow-blue white-black) enable color vision.

Young-Helmholtz Trichromatic (three-color) Theory

The retina contains three different color receptors -one most sensitive to red one to green one to blue -which when stimulated in combination can produce the perception of any color.

Optic Nerve

the nerve that carries visual information from the eye to the occipital lobes.

Optic Chiasm

the place where the optic nerves from each eye cross.

cornea

the round transparent area that allows light to pass into the eye

lens

the transparent structure that focuses light onto the retina

retina

inner membrane of the eye that receives information about light using rods and cones.

pupil

opening at the center of the iris which controls the amount of light entering the eye. Dilates and Constricts.

visual capture

the tendency for vision to dominate the other senses.

rods

sensory cells that are very sensitive to light. They work best in low light but have low acuity.

cones

sensory cells responsible for color vision. They work better in bright light and have high acuity.

fovea

a small dimple in the middle of the retina that is the center of the eye's sharpest vision and the location of most color perception.

color constancy

We perceive familiar objects as having consistent color even if changing illumination alters the wavelengths reflected by the object.

shape constancy

we perceive the form of familiar objects as constant even while our retinal images of them change.

Lightness Constancy

(also called brightness constancy) we perceive an object as having a constant lightness even while its illumination varies.

Size Constancy

we perceive objects as having a constant size even while our distance from them varies.

visual cliff

lab device for testing depth perception in infants and young animals.

Retinal Disparity

your brain compares the two slightly different images it receives from both eyes to compute distance.

convergence

this refers to the extent to which the eyes converge inward when looking at an object.

Relative Size

If we assume two objects are similar in size

Interposition

If one object partially blocks our view of another

Relative Clarity

We perceive hazy objects as farther away than sharp

Texture Gradient

A gradual change from a coarse

Relative Height

We perceive objects higher in our field of vision as farther away.

Linear Perspective

parallel lines such a RR tracks

Light and Shadow

nearby objects reflect more light to the eye dimmer object seen farther away