Transduction the process by which external inputs are

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Transduction: the process by which external inputs are translated into a form the brain can understand. The Human Eye - The projection of the image on the retina is flipped upside down and reversed; our brain then changes it back to the right way for us to understand what we are presently seeing - Sensitivity: the ability to detect the presence of dimly lit objects - Acuity: the ability to see in high detail - Accommodation: the process of adjusting the configuration of the lenses to bring images into focus on the retina Eye Sight Problems: Failure to Accommodate 1. Normal Vision: eye is the proper size and cornea bends the light appropriately to see the image clearly. 2. Myopia/Nearsighted: eye is too elongated, or the cornea or lens bend the light too much, the point of focus falls in front of the retina.
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3. Hyperopia/Farsighted: point of focus is short of the retina, usually because the eye is too small or because the cornea or lens don’t bend the light enough. Light: Electromagnetic Radiation - Light is a type of electromagnetic energy; reflected or emitted from objects in the form of (electrical and magnetic) waves that can travel through space - Different animals have different numbers of cones, thus influencing their color vision: Mice: only have one photo receptors, see only in black and white Dogs: have two photo receptors, see in green, yellow, and blue Birds: have four photo receptors, able to see in ultraviolet light Mantis Shrimp: have up to sixteen photo receptors, able to see UV light, regular light, and polarized light - Color/Hue: determined by wavelength - Brightness: determined by amplitude of waves - Saturation: determined by purity of the light Object Color - Objects absorb some wavelengths of light and reflect others - What we perceive from the object is from the light that is reflected back off the object and into our eyes Trichromatic Theory (Young and Helmholtz, 1852) - Based off of the three types of cones in the retina that respond to different wavelengths: 1. Long Cones: respond to long wavelengths (red) 2. Medium Cones: respond to medium wavelengths (green) 3. Short Cones: responds to short wavelengths (blue) - All colors come from different patterns of activation in these three types of cones - This theory is not effective in explaining after images Opponent-Process Theory (Hering, 1878) - Cones are stimulated by particular wave lengths in the visual light spectrum - Cones for each wavelength are arranged in pairs, with each pair responding to the complementary wavelength of the other (signals are sent to the brain, where only one of the two in each pair is sent, the other inhibited) - Pairs include: Red and green, blue and yellow, black and white Theory Accuracy - Both theories are correct in explaining how the human eye and brain perceive light and color - There are three types of cones that respond to different wavelengths (Early processing) - There are cells in the retina (ganglion), thalamus, and visual cortex, that respond in opposite ways to complementary colors (Late processing) Perception:
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