Presentation is loading. Please wait.

Presentation is loading. Please wait.

Vision.

Published byDwight Willis Modified over 5 years ago

Similar presentations

Presentation on theme: "Vision."— Presentation transcript:

1 Vision

2 Transduction In sensation, the transformation of stimulus energy into neural impulses (light=sight, sound=hearing, chemicals=smell and taste.) Phototransduction: Conversion of light energy into neural impulses that the brain can understand. OBJECTIVE 4| Define transduction, and specify the form of energy our visual system converts into neural messages our brain can interpret.

3 The Stimulus Input: Light Energy
Visible Spectrum Both Photos: Thomas Eisner

4 What makes up a light wave?

5 Light Characteristics
Wavelength (hue/color) Intensity (brightness) Saturation (purity)

6 Wavelength The distance from the peak of one light wave to the peak of the next. The distance determines the hue (color) of the light we perceive.

7

8 Different wavelengths of light result
Wavelength (Hue) Violet Indigo Blue Green Yellow Orange Red 400 nm 700 nm Short wavelengths Long wavelengths Different wavelengths of light result in different colors.

9 Intensity The amount of energy in a light wave.
Determined by the height of the wave. The higher the wave the more intense the light is.

10 Intensity (Brightness)
Intensity Amount of energy in a wave determined by the amplitude. It is related to perceived brightness.

11 Intensity (Brightness)
Blue color with varying levels of intensity. As intensity increases or decreases, blue color looks more “washed out” or “darkened.”

12 Purity (Saturation) Monochromatic light added to green and red
Saturated Saturated Monochromatic light added to green and red makes them less saturated.

13 Represents all three characteristics of light stimulus on this model.
Color Solid Represents all three characteristics of light stimulus on this model.

14 The Eye OBJECTIVE 5| Describe the major structure of the eye, and explain how they guide the incoming ray of light toward the eye’s receptor cells.

15 Clip: the eye and transduction: https://www. youtube. com/watch

16 Parts of the eye Cornea: Transparent tissue where light enters the eye. Iris: Muscle that expands and contracts to change the size of the opening (pupil) for light. Lens: Focuses the light rays on the retina. Retina: Contains sensory receptors that process visual information and sends it to the brain. Pupil: adjustable opening in the center of the eye.

17 The Lens Lens: Transparent structure behind the 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.

18 Vision Acuity- the sharpness of vision
Nearsightedness- condition in which nearby objects are seen more clearly than distant objects because distant objects in front of retina Farsightedness- condition in which faraway objects are seen more clearly than near objects because the image of near objects is focused behind retina

19

20 Nearsighted Vision

21 Farsighted Vision

22 Optic Nerve, Blind Spot & Fovea
Optic nerve: Carries neural impulses from the eye to the brain. Blind Spot: Point where the optic nerve leaves the eye because there are no receptor cells located there. This creates a blind spot. Fovea: Central point in the retina around which the eye’s cones cluster.

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

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

25 Retinal ganglion cells---go back to 5.3 and then to 5.4
5.4a is the cover of a catalog and students complained of seeing gray spots The grid pattern is called the Hermann grid after the German physiologist who first discovered it The elusive gray spots can be explained in terms of the receptive fields of the retinal ganglion cells Some of the cells are an on center surrounded by an off (like a donut). Light has opposite, antagonistic effects

26 Test your Blind Spot Use your textbook or the handout (p. 207). Close your left eye, and fixate your right eye on the black dot. Move the page towards your eye and away from your eye. At some point the car on the right will disappear due to a blind spot.

27 Visual Information Processing
Optic nerves connect to the thalamus in the middle of the brain, and the thalamus connects to the visual cortex. OBJECTIVE 7| Discuss the different levels of processing that occur as information travels from the retina to the brain’s cortex.

28 Eye drawing: for bag of tricks

29 Feature Detection Nerve cells in the visual cortex respond to specific features, such as edges, angles, and movement. Ross Kinnaird/ Allsport/ Getty Images

30 Shape Detection Specific combinations of temporal lobe activity occur as people look at shoes, faces, chairs and houses. Ishai, Ungerleider, Martin and Haxby/ NIMH

31 Perception in Brain Our perceptions are a combination of sensory (bottom-up) and cognitive (top-down) processes.

32 From Sensation to Recognition
Tim Bieber/ The Image Bank

33 Parallel Processing The processing of several aspects of a problem simultaneously. Motion Form Color Depth

34 Visual Information Processing
Processing of several aspects of the stimulus simultaneously is called parallel processing. The brain divides a visual scene into subdivisions such as color, depth, form and movement etc. OBJECTIVE 8| Discuss parallel processing and discuss its role in visual processing.

35 How do we see in color? What color is this dragon?

36 Color The dragon is anything but red.
The dragon rejects the long wavelengths of light that to us are red- so red is reflected of and we see it. Also, light has no real color. It is our mind that perceives the color.

37 Two major color theories

38 Theories of Color Vision
Trichromatic theory: Based on behavioral experiments, Young and Helmholtz suggested that the retina should contain three receptors that are sensitive to red, blue and green colors. Standard stimulus OBJECTIVE 9| Explain how the Young-Helmholtz and opponent-process theories help us understand color vision. Comparison stimulus Max Medium Low Blue Green Red

39 Young-Helmholtz Trichromatic (three color) Theory
Realized that any color can be created by combining the light waves of three primary color- RED GREEN BLUE So they guessed that we have 3 different types of receptor cells in our eyes. Together they can pick any combination of our 7 million color variations. Most colorblind people simply lack cone receptor cells for one or more of these primary colors.

40 Photoreceptors Blue Cones Green Cones Red Cones MacNichol, Wald and Brown (1967) measured directly the absorption spectra of visual pigments of single cones obtained from the retinas of humans. Short wave Medium wave Long wave

41 Color Blindness Genetic disorder in which people are blind to green or red colors. This supports the Trichromatic theory. Ishihara Test

42 Color Blindness Simulators
Check out these sites to see what a color blind person sees (normal, red blind, blue blind, monochromatic)

43 Opponent-Process Theory
We cannot see certain colors together in combination (red-green, blue-yellow, and white-black). These are antagonist/ opponent colors.

44 Opponent Process Theory
Hering proposed that we process four primary colors combined in pairs of red-green, blue-yellow, and black-white. Cones Retinal Ganglion Cells

45

46 Opponent Colors Gaze at the middle of the flag for about 30
Seconds. When it disappears, stare at the dot and report whether or not you see Britain's flag. See p. 84 in the high school book for the same idea with the American flag

47 Color Constancy Color of an object remains the same under different illuminations. However, when context changes the color of an object may look different. OBJECTIVE 10| Explain the importance of color constancy. R. Beau Lotto at University College, London

48 Hermann Grid

49 The Scintillation Grid: Bernd Lingelbach

50 Simple Color Aftereffects
Last a few seconds and depend on precise fixation

51

Download ppt "Vision."

Similar presentations

Unit 4(C): Vision Mr. McCormick A.P. Psychology. Do-Now (Discussion)  Raise your hand if you are either nearsighted or farsighted.  What causes Nearsightedness.

Unit 4(C): Vision Mr. McCormick A.P. Psychology. Do-Now (Discussion)  Raise your hand if you are either nearsighted or farsighted.  What causes Nearsightedness.
EXPLORING PSYCHOLOGY (7th Edition in Modules) David Myers PowerPoint Slides Aneeq Ahmad Henderson State University Worth Publishers, © 2008.

EXPLORING PSYCHOLOGY (7th Edition in Modules) David Myers PowerPoint Slides Aneeq Ahmad Henderson State University Worth Publishers, © 2008.
Vision How does our body construct our conscious visual experience?

Vision How does our body construct our conscious visual experience?
Vision Our most dominant sense

Vision Our most dominant sense
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,
Vision Module 13 Psychology 7e in Modules.

Vision Module 13 Psychology 7e in Modules.
Transduction Conversion of one form of energy to another. How is this important when studying sensation? Stimulus energies to neural impulses. For example:

Transduction Conversion of one form of energy to another. How is this important when studying sensation? Stimulus energies to neural impulses. For example:
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.

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 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.
The Eye contains visual sensory receptors focuses light on the retina

The Eye contains visual sensory receptors focuses light on the retina
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