6. Vision

8. Figure 4.1 The Visible Spectrum. By passing a source of white light, such as sunlight, through a prism, we break it down into the colors of the visible spectrum. The visible spectrum is just a narrow segment of the electromagnetic spectrum. The electromagnetic spectrum also includes radio waves, microwaves, X-rays, cosmic rays, and many others. Different forms of electromagnetic energy have wavelengths which vary from a few trillionths of a meter to thousands of miles. Visible light varies in wavelength from about 400 to 700 billionths of a meter. (A meter = 39.37 inches.) Visible Spectrum of Light

10. Figure 4.2 The Human Eye. In both the eye and a camera, light enters through a narrow opening and is projected onto a sensitive surface. In the eye, the photosensitive surface is called the retina, and information concerning the changing images on the retina is transmitted to the brain. The retina contains photoreceptors called rods and cones. Rods and cones transmit sensory input back through the bipolar neurons to the ganglion neurons. The axons of the ganglion neurons form the optic nerve, which transmits sensory stimulation through the brain to the visual cortex of the occipital lobe. The Human Eye

11. Figure 4.2 The Human Eye. In both the eye and a camera, light enters through a narrow opening and is projected onto a sensitive surface. In the eye, the photosensitive surface is called the retina, and information concerning the changing images on the retina is transmitted to the brain. The retina contains photoreceptors called rods and cones. Rods and cones transmit sensory input back through the bipolar neurons to the ganglion neurons. The axons of the ganglion neurons form the optic nerve, which transmits sensory stimulation through the brain to the visual cortex of the occipital lobe. The Human Eye

18. Figure 4.6 The Color Wheel . A color wheel can be formed by bending the colors of the spectrum into a circle and placing complementary colors across from one another. When lights of complementary colors such as yellow and violet-blue are mixed, they dissolve into neutral gray. The afterimage of a color is its complement. Color Wheel

19. Visual Perception

21. Afterimage

22. Figure 4.9 Three Cheers for the…Green, Black, and Yellow . Don’t be concerned. We can readily restore Old Glory to its familiar hues. Place a sheet of white paper beneath the book and stare at the black dot in the center of the flag for at least 30 seconds. Then remove the book. The afterimage on the paper beneath will look familiar. Color Illusion

23. Muller-Lyer Are the vertical lines equal in length?

24. Hering-Helmholtz Are the horizontal lines straight or curved?

26. Figure 4.10 Plates from a Test for Color Blindness . Can you see the numbers in these plates from a test for color blindness? A person with red–green color blindness would not be able to see the 6, and a person with blue–yellow color blindness would probably not discern the 12. Color Blindness

29. Figure 4.13 The Rubin Vase . A favorite drawing used by psychologists to demonstrate figure–ground perception. Part A is ambiguous, with neither the vase nor the profiles clearly the figure or the ground. In part B, the vase is the figure; in part C, the profiles are. The Rubin Vase

30. Figure 4.14 Necker Cube . Ambiguity in the drawing of the cube makes perceptual shifts possible. Therefore, the darker tinted surface can become either the front or back of the cube. Necker Cube

32. Figure 4.15 Some Gestalt Laws of Perceptual Organization . These drawings illustrate the Gestalt laws of proximity, similarity, continuity, and closure. Perceptual Organization

36. Figure 4.17 The Effects of Interposition . The four circles are all the same size. Which circles seem closer? The complete circles or the circles with chunks bitten out of them? Effects of Interposition

38. Figure 4.18 Shadowing as a Cue for Depth. Shadowing makes the circle on the right look three-dimensional. Shadowing as a cue for depth

41. Figure 4.19 Brightness Constancy. The orange squares within the blue squares are the same hue, yet the orange within the dark blue square is perceived as brighter. Why? Brightness Consistency

42. Figure 4.20 Shape Constancy. When closed, this door is a rectangle. When open, the retinal image is trapezoidal. But because of shape constancy, we still perceive it as rectangular. Shape Constancy

43. Hearing

45. Figure 4.24 Sound Waves of Various Frequencies and Amplitudes. Which sounds have the highest pitch? Which are loudest? Sound Waves

46. Decibel Ratings of Familiar Sounds Zero dB is the threshold of hearing. You may suffer hearing loss if you have prolonged exposure to sounds of 85 to 90 dB. Decibel Ratings

49. Figure 4.26 The Human Ear. The outer ear funnels sound to the eardrum. Inside the eardrum, vibrations of the hammer, anvil, and stirrup transmit sound to the inner ear. Vibrations in the cochlea transmit the sound to the auditory nerve by way of the basilar membrane and the organ of Corti. The Ear

53. Smell & Taste

57. The Skin Senses

59. Sensation & Perception and Virtual reality

64. Figure 4.28 Perception of Pain. Pain originates at the point of contact, and the pain message to the brain is initiated by the release of prostaglandins, bradykinin, and substance P. Pain Perception