Presentation is loading. Please wait.

Presentation is loading. Please wait.

THE VISUAL SYSTEM SENSE OF SIGHT.

Published byLisa Cox Modified over 5 years ago

Similar presentations

Presentation on theme: "THE VISUAL SYSTEM SENSE OF SIGHT."— Presentation transcript:

1 THE VISUAL SYSTEM SENSE OF SIGHT

2 THE VISUAL SYSTEM Photoreception: detection of light, perceived as sight Stimulus: visible light Sense organ: eyes Function: seeing Phototransduction: transforms light waves into electrochemical impulses that the brain can interpret

3 VISIBLE LIGHT

4 LIGHT WAVE PROPERTIES Light has 3 characteristics:
Wavelength: frequency (determines color/hue) longer/wider = lower frequency = reddish shorter/narrower = higher frequency = bluish Wave amplitude: intensity (determines brightness) shorter = less intensity = duller taller = more intensity = brighter Purity: quality (determines saturation) richness of color

5

6 STRUCTURES OF THE EYE Cornea: clear front membrane; bends the light as it enters the eye Sclera: protective white outer layer; helps maintain the eye’s shape Iris: colored ring of muscle; dilates/constricts pupil Pupil: seemingly black, adjustable opening; regulates amount of light that enters the eye Lens: transparent flexible structure; changes shape to focus light on retina Vitreous humor: thick clear gel; maintains the eye’s form/shape Retina: multilayered light sensitive surface; absorbs light, processes images, and sends information to the brain contains rods and cones

7 ACCOMMODATION The process by which the eye’s lens changes shape (curvature) to focus far or near objects on the retina. Distant focus/far object = long, flattened lens Close focus/near object = short, rounded lens

8

9 RETINA The multilayered light-sensitive surface in the eye that records electromagnetic energy and converts it to neural impulses for processing in the brain. Rods: photoreceptor cells; peripheral vision Cones: photoreceptor cells; color vision Fovea: central focal point; cones only; visual acuity Optic disk: blind spot; hole in retina; no receptor cells; where optic nerves exits the eye Optic nerve: bundle of ganglion axons; sends neural impulses to brain

10 PHOTORECPTORS Rods Cones Long and thin 120 million
Black, white, gray vision Night/twilight vision Sensitive to low illumination Peripheral vision Located in periphery of retina Dark adaptation: eyes become more sensitive to light in low illumination Short and fat 6 million Color vision Daylight vision Sensitive to high illumination Fine detailed vision Concentrated in center of retina Light adaptation: eyes become less sensitive to light in high illumination

11 FEATURE DETECTORS David Hubel and Torsten Wiesel (1963)
Special neurons in the brain's visual system that respond to particular features of complex stimuli. Features such as lines, angles, sizes, shapes, and movement

12 PARALLEL PROCESSING The simultaneous distribution of information across different neural pathways. The brain processes color, motion, form and depth all at once.

13 Opponent-Process Theory
COLOR VISION Trichromatic Theory Opponent-Process Theory Thomas Young and Hermann von Helmholtz (1802/1852) States that color perception is produced by three types of cone receptors in the retina that are particularly sensitive to different, but overlapping, ranges of wavelengths. Red, blue, green Supported by color blindness Edwald Hering (1878) States that cells in the visual system respond to complementary pairs. Pairs: Blue-yellow Red-green Black-white Supported by afterimages

14 Substractive Color Mixing
TRICHROMATIC THEORY Additive Color Mixing Substractive Color Mixing If three colors of light are mixed, addition of all wavelengths result in white. If three colors of pigments are mixed, subtraction of all wavelengths result in black.

15 COLOR BLINDNESS A deficiency in the ability to distinguish between certain colors. Generally involves the inability to distinguish between shades of red and green Usually an inherited, genetic disorder More common in men than women True color blindness is a total lack of color vision Rare Supports trichromatic theory

16 OPPONENT-PROCESS THORY
A given cell might be excited by red and inhibited by green, a different cell might be excited by yellow and inhibited by blue, whereas another cell might be excited by black and inhibited by white.

17 AFTERIMAGES A visual image that persists after a stimulus is removed.
Supports opponent-process theory

18 VISION LOSS Nearsightedness Farsightedness
Myopia: A condition in which nearby objects are seen more clearly than distant objects. Lens focuses image of distant objects in front of retina Need corrective lenses to see distant objects (puts image on retina) Hyperopia: A condition in which faraway objects are seen more clearly than near objects. Lens focuses near objects behind retina Need corrective lenses to see near objects (puts image on retina)

19 VISION LOSS

Download ppt "THE VISUAL SYSTEM SENSE OF SIGHT."

Similar presentations

Parts of the Eye - Pupil.

Parts of the Eye - Pupil.
Vision Our most dominant sense

Vision Our most dominant sense
Vision Transduction Wavelength

Vision Transduction Wavelength
Sensation Chapter 5 Myers AP Psychology. Transduction  Conversion of one form of energy into another.  In sensation, the transforming of stimulus energies,

Sensation Chapter 5 Myers AP Psychology. Transduction  Conversion of one form of energy into another.  In sensation, the transforming of stimulus energies,
DO NOW: What do you know about our sense of sight and vision? What parts of the eye do you know? What do you know about light?

DO NOW: What do you know about our sense of sight and vision? What parts of the eye do you know? What do you know about light?
Module 12 Vision.  Transduction  conversion of one form of energy to another  in sensation, transforming of stimulus energies into neural impulses.

Module 12 Vision.  Transduction  conversion of one form of energy to another  in sensation, transforming of stimulus energies into neural impulses.
1 PSYCHOLOGY (8th Edition, in Modules) David Myers PowerPoint Slides Worth Publishers, © 2007 PowerPoint Slides Worth Publishers, © 2007.

1 PSYCHOLOGY (8th Edition, in Modules) David Myers PowerPoint Slides Worth Publishers, © 2007 PowerPoint Slides Worth Publishers, © 2007.
Vision By: Bethany, Iqra, Clint, Cameron, Nick. The Process Light enters eye through the cornea Then, it goes through the pupil which is surrounded by.

Vision By: Bethany, Iqra, Clint, Cameron, Nick. The Process Light enters eye through the cornea Then, it goes through the pupil which is surrounded by.
The Visual System: The Structure of the Visual System Module 9: Sensation.

The Visual System: The Structure of the Visual System Module 9: Sensation.
VISION.

VISION.
Vision – our most dominant sense. Vision Purpose of the visual system –transform light energy into an electro-chemical neural response –represent characteristics.

Vision – our most dominant sense. Vision Purpose of the visual system –transform light energy into an electro-chemical neural response –represent characteristics.
Sensation and Perception Sensations: take it in Sensations: take it in Perception: what we do with it Perception: what we do with it.

Sensation and Perception Sensations: take it in Sensations: take it in Perception: what we do with it Perception: what we do with it.
Mr. Koch AP Psychology Forest Lake High School

Mr. Koch AP Psychology Forest Lake High School
The Eye. Energy v. Chemical senses Energy SensesChemical Senses.

The Eye. Energy v. Chemical senses Energy SensesChemical Senses.
The Visual System. The Nature of Light Electromagnetic Spectrum – An energy spectrum that includes X-rays, radar, and radio waves – A small portion of.

The Visual System. The Nature of Light Electromagnetic Spectrum – An energy spectrum that includes X-rays, radar, and radio waves – A small portion of.
Myers EXPLORING PSYCHOLOGY Module 14 Introduction to Sensation and Perception: Vision James A. McCubbin, PhD Clemson University Worth Publishers.

Myers EXPLORING PSYCHOLOGY Module 14 Introduction to Sensation and Perception: Vision James A. McCubbin, PhD Clemson University Worth Publishers.
.  Sensation: process by which our sensory receptors and nervous system receive and represent stimulus energy  Perception: process of organizing and.

.  Sensation: process by which our sensory receptors and nervous system receive and represent stimulus energy  Perception: process of organizing and.
Psychology, Ninth Edition in Modules David Myers PowerPoint Slides Aneeq Ahmad Henderson State University Worth Publishers, © 2010.

Psychology, Ninth Edition in Modules David Myers PowerPoint Slides Aneeq Ahmad Henderson State University Worth Publishers, © 2010.
VISION From Light to Sight. Objective To describe how the receptor cells for vision respond to the physical energy of light waves and are located in the.

VISION From Light to Sight. Objective To describe how the receptor cells for vision respond to the physical energy of light waves and are located in the.
Eye is the window to our soul. English physicist Sir Isaac Newton, in an experiment, observed that a ray of sunlight, or white light, was broken up into.

Eye is the window to our soul. English physicist Sir Isaac Newton, in an experiment, observed that a ray of sunlight, or white light, was broken up into.

Similar presentations

Ads by Google