1 / 28

Psychology 210

Psychology 210. Lecture 4 Kevin R Smith. Vision. Sensory System The eye Exactly what we sense from our environment Perceptual System The brain How we put together what we sense into a visual picture. The brain constructs our environment.

ora-kerr
Télécharger la présentation

Psychology 210

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Psychology 210 Lecture 4 Kevin R Smith

  2. Vision • Sensory System • The eye • Exactly what we sense from our environment • Perceptual System • The brain • How we put together what we sense into a visual picture

  3. The brain constructs our environment

  4. Multiple experiences of an item lead to different interpretations

  5. The Visual Sensory System • Light is made of waves • Wavelength • Different colors have different wavelengths • Amplitude • Different amplitudes lead to differences in brightness • Visible spectrum • 400nm to 750nm • ROY G BIV • Short wavelengths are near blue and violet • Long wavelengths are near red and orange

  6. Properties of Light and Waves • The color of an object is determined by its abilities across two dimensions • Absorption • Reflection • Colors that are reflected are the colors that we see • A red sweater is red because it reflects wavelengths that we perceive as red • Other wavelengths would be absorbed and NOT visible as a color for this sweater

  7. Properties of Light and Waves • Black is a color that absorbs all other colors • ie. It is the absence of reflected color • White is a color that reflects all other colors • ie. It is the presence of all colors • prisms White object

  8. Properties of Light and Waves • Refraction • The change of direction of the waves • Occurs in water • Different substances refract light differently

  9. The eye • Sclera • Outer covering that protects the eye and gives it shape • Cornea • Protective covering for the eye • Begins to bend the light waves and focus them • Aqueous humor • Fluid filled area behind the cornea • Provides nutrients to the cornea and lens

  10. Parts of the eye • Pupil • Area in the center of the eye • Controls the amount of light that enters • Iris • The muscle that controls the widening or narrowing of the pupil • Lens • Bend to focus light onto the retina • Accommodation • The process of the bending of the lens to properly focus the image on our retina • Vitreous humor • Gives the eye its shape • Does not regenerate • The vitreous humor your born with is what you still have • Floaters • Debris that gathers in the vitreous humor and casts shadows onto the retina

  11. Retina • Translates light waves into an electrical signal our brain can process • Concave • Object on retina is translated upside-down • Photoreceptors • Rods and cones • Optic Disk/ Optic Nerve • Area in the retina where nerves and blood vessels exit the eye • Forms a blind spot • Fovea • Area in center of retina

  12. Layers of the Retina • Four main types of visual processing neurons • Ganglion cell layer • Amacrine and bipolar cell layer • Horizontal cells • Visual Sensory Neurons • Photoreceptors • Rods • Cones

  13. Rods and Cones • Where a sensory signal (light waves) gets changed into electrical energy • Process called transduction • Rods • Sensitive to black and white • Most of them in periphery • Cones • Sensitive to color • Most of them in fovea

  14. Rods • Contain rhodopsin • 120 million in a human eye • Responsible for night vision • Very sensitive to light • Very poor clarity

  15. Cones • 6 million in the human eye • Responsible for vision in bright light • Excellent clarity • 3 different types with different pigments

  16. Cones • Three different types • Blue, short • Green, medium • Red, long

  17. Integrate information from the photoreceptors Transfer that information to bipolar cells Horizontal Cells

  18. Bipolar cells Amacrine Cells Bipolar cells Horizontal cells • Receive input from horizontal cells and photoreceptors • Transmit information to amacrine cells • Contain receptive fields • Antagonistic center-surround organization photoreceptors

  19. Amacrine Cells • Respond to changes in the visual environment • Connect bipolar cells, ganglion cells, and other amacrine cells

  20. Ganglion cells • Receive input from bipolar and amacrine cells • Same center-surround receptive fields found in bipolar cells • On-center bipolar fields connect to on-center ganglion cells • Off-center bipolar fields connect to off-center ganglion cells

  21. What do receptive fields do? • On-center and off-center fields provide for greater acuity • Large unchanged surfaces don’t activate the neurons as well as changing surfaces with lines, cracks, and ends

More Related