1. Journal https://en.wikiversity.org/wiki/Introduction_t o_psychology/Psy102/Tutorials/Sensation_an d_perception

2. Vision

3. http://www.exploratorium.edu/exhibits/bird_i n_a_cage/bird_in_a_cage.html http://www.exploratorium.edu/exhibits/bird_i n_a_cage/bird_in_a_cage.html

4. Transduction In sensation, the transformation of stimulus energy (sights, sounds, smells) into neural impulses. Examples: Phototransduction: The conversion of light energy into neural impulses that the brain can understand. Acoustical Transduction: Conversion of sound waves into neural impulses in the hair cells of the inner ear.

5. Visible Spectrum The Stimulus Input: Light Energy Humans detect visible light. Bee’s detect radiation from UV into violet/blue end of the visible spectrum. The energy of red light does NOT stimulate bees receptors – so transduction does NOT occur.

6. Physical Characteristics of Light  Light travels as an electromagnetic wave.  Sounds travels as a wave of air pressure. Physical Characteristics LightSound WavelengthColorPitch Amplitude(Intensity)WavelengthVolume

7. Wavelength (Hue) Hue (color) is the dimension of color determined by the wavelength of the light. Wavelength is the distance from the peak of one wave to the peak of the next.

8. Light: Wavelength (Hue) Different wavelengths of light result in different colors. 400 nm 700 nm Long wavelengths Short wavelengths Violet IndigoBlue Green Yellow OrangeRed

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

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

11. The Eye

12. Parts of the eye 1.Cornea: Transparent tissue where light enters the eye. 2.Iris: Muscle that expands and contracts to change the size of the opening (pupil) for light. 3.Lens: Focuses the light rays on the retina. 4.Retina: Contains sensory receptors that process visual information and sends it to the brain.

13. 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.

14. Retina Retina: The light- sensitive inner surface of the eye, containing receptor rods and cones in addition to layers of other neurons (bipolar, ganglion cells) that process visual information. Bipolar cells receive messages from photoreceptors and transmit them to ganglion cells, which converge to form the optic nerve.

15. Photoreceptors E.R. Lewis, Y.Y. Zeevi, F.S Werblin, 1969

16. 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. Fovea: Central point in the retina around which the eye’s cones cluster.

17. Test your Blind Spot 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.

18. Bipolar & Ganglion Cells Bipolar cells receive messages from photoreceptors and transmit them to ganglion cells, which converge to form the optic nerve.

19. Visual Information Processing Optic nerves connect to the thalamus in the middle of the brain, and the thalamus connects to the visual cortex.

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

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

22. 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, movement, etc.

23. From Sensation to Recognition

24. Color Vision Trichromatic theory: Young and von Helmholtz suggested that the eye must contain three receptors that are sensitive to red, blue and green colors. Blue Green Red Medium Low Max Standard stimulus Comparison stimulus

25. 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.

26. Opponent-Process Theory Opposing retinal processes enable color vision. Red-Green Yellow-Blue White-Black Cells stimulated by green are inhibited by red. Afterimages: We tire our green response by staring at green. We then stare at white (all colors) Only red will fire normally.

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

28. Both Theories  The retina’s red, blue and green cones respond in varying degrees to different color stimuli: The Trichromatic Theory  Then the signal is processed by the nervous system’s opponent process cells as it travels to the visual cortex.

29. Vision and Balance Everyday balance: – Stand up and make sure that there is space for balancing – How is it that you remain standing without falling over? Without thinking about it? What sensory and perceptual processes are occurring?

30. Challenging the vestibular system One-foot balances with eyes open and closed 1 foot, open eyes: stand on one foot for 30 seconds with your eyes open 1 foot, closed eyes: close your eyes and balance on one foot. 1 foot, closed eyes, dizzy: spin around a few times, then balance on one foot and close your eyes. – Why is it more difficult?

31. Challenging the visual system One foot balances, one eye, visual disruption – Stand on one foot – Open the eye on the same side as the foot they are standing on and look at some convenient point or spot. – Very carefully and gently press with your index finger on the same side of your open eye against the eyelid of the eye. Continue to look the spot/object while gently pressing your eye. – Swap sides (open eye, leg, finger)

32. Depth Perception Seeing objects in three dimensions enabling us to estimate their distance from us. – Binocular cues: provide depth information when viewing a scene with both eyes. – Why are we better at catching with two eyes? Do you know someone with one eye? How do they adapt? Binocular vision: – Close one eye, point your two pointer fingers toward each other, then bring them together quickly.