PSYC 406 Lecture 2: The Beginnings of the Perceptual Process
Document Summary
Light is reflected and focused to create an image on the retina (proximal stimulus) Visible human spectrum is 400 to 700 nanometers. Signals travel in a network of neurons. Cornea and lens focus light to image on retina. Rods and cones are eye receptors, containing visual pigment. Optic nerve carries information from retina towards brain. Cornea (fixed) is responsible for 80% of focusing power, 20% from lens (adjusts shape) Fovea is only cones, no rods (point of central focus) Peripheral retina has more rods than cones. Creates a blind spot on the retina. Corrective lenses needed for close activities, like reading. Refractive myopia: cornea or lens bends too much light. Contain visual pigments (opsin, a protein, and retinal, light sensitive molecule) Visual transduction occurs when retinal absorbs a photon. Dark adaptation is process of increasing sensitivity in dark. Rods and cones both work, but rods work longer.
