Sensation and perception notes ch 5 PDF

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Sensation and perception notes
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Psychology notes Sensation and Perception (Ch.4) 1. Sensation: The process of receiving stimulus energies from the external environment. a. The brain receives input from the sensory organs. b. Photoreception i. Detection of light 1. Vision c. Mechanoreception i. Detects movement 1. Hearing d. Chemoreception i. Detection of chemical stimuli e. Sensory receptors i. Specialized cells that selectively detect and transmit sensory information to the brain. ii. The frequency that a signal fires with increase the intensity f. Sensory store i. Part of your memory in which we pull in information from the environment ii. Iconic memory: Up to 1 second (Visual) iii. Echoic Memory: Up to 4 seconds (Auditory) g. Synesthesia i. One sense induces an experience in another sense h. Sensory thresholds i. Absolute threshold: The minimum amount of energy an organism can detect 50% of the time ii. Difference thresholds: How much stimulus change is necessary for detection i. Weber’s Law i. To be perceived as different, two stimuli must differ by a constant minimum percentage. 2. Perception: The process of organizing and interpreting sensory information. a. The brain makes sense out of the input from the sensory organs. b. Attention i. Focusing your awareness ii. Selective attention 1. Cocktail party effect 3. Bottom-up processing a. Initiated by sensory input b. Starts with the environment i. Trying to make sense of something you haven’t seen before c. Outside world’s influence on perception

4. Top-down Processing a. Initiated by cognitive processing b. Starts with the brain c. Internal/mental worlds influence on perception i. Expectations and prior understanding 5. Properties of Light a. Wavelength: Distance between peaks i. Perceived as hue ii. Some are beyond human sensation b. Amplitude: Height of the wave i. Perceived as brightness c. Purity: Mixture of wavelengths i. Perceived as saturation 6. Structure of the eye a. Photo-Receptor cells i. Rods 1. Sensitive to even dim light, but not color 2. We have about 120 million Rods ii. Cones 1. Respond to color 2. Operate best under high illumination 3. We have about 6 million cones 4. Main concentration is in the back of the eye iii. Retina 1. Fovea: Densely populated with cones 2. Blind spot: Where the optic nerve leaves the eyeball 7. Visual Processing a. Feature Detectors i. Highly specialized cells in the visual cortex ii. Size, shape, color, movement, or combination iii. Brain “learns” perception 8. Color vision theories a. Trichromatic theory i. Three types of color receptors ii. Blue, green, red b. After image i. Sensation remains after a stimulus is removed ii. Trichromatic theory cannot explain afterimages c. Opponent process theory i. Complementary color pairs 9....