Gestalt Principles Perceptual Constancies Basic Principles Visual Illusions

Gestalt Principles Perceptual Constancies Basic Principles Visual Illusions Perception We are here Sensation Vision Theories Depth Perception The Eye Pain Other Senses Taste Hearing The Ear Smell Theories

Essential Task 4 -2: • Vision - relevant anatomical structures – Path light travels (cornea, pupil, iris, lens, and retina) – optic nerve, blind spot and fovea – Transduction (rods and cones) • Color Vision – The trichromatic theory of color vision • Color Blindness – Opponent process theory of color vision • After-Image Effect

Vision • Our most dominating sense. • Visual Capture

Phase One: Gathering Light • • • The height of a wave gives us it’s intensity (brightness). The length of the wave gives us it’s hue (color). ROY G BIV The longer the wave the more red. The shorter the wavelength the more violet.

Phase Two: Getting the light in the eye

Rods and Cones

Phase Three: Transduction

Transduction Continued • Order is Rods/Cones to Bipolar to Ganglion to Optic Nerve. • Sends info to thalamus • Then sent to cerebral cortexes.

Phase Four: In the Brain We have specific cells that see the lines, motion, curves and other features of this turkey. These cells are called feature detectors. • Goes to the Visual Cortex located in the Occipital Lobe of the Cerebral Cortex. • Feature Detectors. • Parallel Processing

Parallel Processing • Multitasking ability that lets our brain handle many aspects simultaneously. • In vision, we work separately and simultaneously on color, movement, depth and form.

Color Vision Two Major Theories

Trichromatic Theory Three types of cones: • Red • Blue • Green • These three types of cones can make millions of combinations of colors. • Does not explain color blindness well.

With paint, the more colors you mix, the fewer wavelengths of light will be reflected. All paint colors together = black. With light, the more colors you mix, the more wavelengths of light will be reflected. All light colors together = white.

Opponent-Process theory Further up in the optic nerve, neurons work in pairs to help process color vision signals Red/Green • Yellow/Blue • Black/White • If one color is stimulated, the other is inhibited.

Color Blindness Dichromatic problems with reds and greens Dichromatic Problems with Blues and Greens

Color Blindness Tests

Color Constancy: perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object. our perception of color depends on context

Neuroscience of ghosts!