ch04

Psychology in Action

  • Notes
  • 38
  • 100% (2) 2 out of 2 people found this document helpful

This preview shows page 4 - 6 out of 38 pages.

II. HOW WE SEE AND HEAR A. Vision - The physical stimulus for vision is light, a form of energy that is part of the electromagnetic spectrum. The wavelength of light determines its hue, or color; and the amplitude, or height, of the light wave determines its brightness. The function of the eye is to capture light and focus it on the visual receptors that convert light energy into neural impulses. The major parts of the eye include the cornea, the pupil, the iris, the lens, and the retina. All light enters the eye through the cornea which protects the eye and bends incoming light rays toward the lens. Light then enters through an opening called the pupil. The pupil is surrounded by the iris which dilates or constricts to vary the amount of light entering the eye. Behind the pupil and iris is the lens, a clear elastic structure that can change its shape to Instructor’s Resource Guide                              Chapter 4                                            Page   113                                                                            
Image of page 4

Subscribe to view the full document.

focus an image on the retina at the back of the eye. The lens thins to focus light on the retina from distant objects and bulges to focus light from near objects. The retina is the back layer of the eye that contains the visual receptor cells. The visual receptors, called photoreceptors, are the rods and cones. The rods are very sensitive to light and enable individuals to see at night. The cones are specialized for bright light conditions and enable individuals to see close and fine detail. Nearsighted can be caused by a longer than normal eyeball or a too sharply curved cornea. Farsightedness is caused by a shorter than normal eyeball. Both conditions are easily remedied with corrective lenses. Two traditional color theories: the trichromatic theory and the opponent-process theory are proposed. The trichromatic theory proposes that three kinds of color systems are maximally sensitive to blue, green, and red. The opponent-process theory proposes that, indeed, three color systems exist, but that each is sensitive to two opposing colors—blue and yellow, red and green, and black and white. These systems work in an on-off fashion (for example, a person may see blue or yellow, but not both at the same time). According to the modern dual process theory, the trichromatic system operates at the level of the retina while the opponent- process system occurs at the level of the brain. Some people have a small genetic deficiency and may perceive only two colors and are called dichromats. Those who are sensitive to only the black-white system is called monochromats, and they are totally color blind.
Image of page 5
Image of page 6
You've reached the end of this preview.
  • '
  • NoProfessor
  • Resource Guide                               Chapter

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern