PSY-101 1st EditionLecture 10Outline of Last LectureI. Sensation vs. PerceptionII. Receptor CellsIII. Two Major Processes in Perceptual ProcessingIV. Sensory Receptors and the BrainOutline of Current Lecture I. Vision- What We SeeCurrent LectureI. Vision- What We Seea. Light is electromagnetic energy that can be described as waves and by its wavelength.b. As wavelength varies, color perception in humans varyc. Wavelength itself is not color- color is an interpretation of wavelengthd. How We Seei. Light is focused by the cornea and lens to project an image on the retinaii. Cornea- clear membrane that covers the front of the eye, does most of the focusing of the imageiii. Pupil and iris- colored part of the eye (iris) and the hole corned by the iris(pupil)1. Controls the amount of light that enters the eye2. Aids in controlling the clarity of the image (smaller pupils, clearer image)iv. Lens- transparent structure behind the pupil1. Focuses the image on the retina2. Changes shape to focus on far to near targets through the processes of accommodationv. Retina- thin, light-sensitive membrane located at the back of the eye, contains sensory receptors for vision1. Rods and cones- sensory receptor cells that respond to lighta. Called Photoreceptorsb. Exposed to light, rods and cones undergo chemical reactions that result in neural signals.i. Cones- most located in the center of the retina1. Fovea- center of retina with all cones and best vision2. Responsible for best acuity3. Responsible for color vision4. Active at daylight or photo pic light levels5. About 6 million in the eyeii. Rods- located in the periphery of the eye1. Responsible for night or scout pic vision2. Have relatively poor acuity3. Takes approximately 30 minutes to adapt to lowest light levels4. About 120 million in eye.e. Color Visioni. Our visual system interrupts differences in the wavelengths of light as color.ii. Rods are color blind, but the cones allow us to see different colorsiii. ROYGBIV1. Wavelength of about 400 nanometers = violet2. Wavelength of about 700 nanometes = red3. In between are orange, yellow, green, blue, and