Sensation - 0. Sensation vs. Perception: Detecting vs....

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Unformatted text preview: 0. Sensation vs. Perception: Detecting vs. interpreting messages from receptors 1. The empiricist view: Perception involves supplementing sensory input with associations 2. The nativist view: Perception involves the mind organizing sensory input based on preexisting categories 3. The modern view: sensation is the transduction of a proximal stimulus into neural signals Sensation The nature of transduction: 4. A proximal stimulus (some form of energy or a chemical) is converted into a neural signal 5. Its intensity is signaled through sensory coding 0. Firing rate 1. Number of neurons firing 6. Its quality is signaled through the nerves or neurones being stimulated 2. And also by the patterns for firing across neurons Before we knew much about transduction, we had psychophysics 7. Assessing the relations between physical variables and mental variables 8. Absolute thresholds 3. The problem of noise & response bias 4. How we measure thresholds 9. Difference thresholds & Weber's law (p. 123) 5. (delta I)/I = c (a constant within a sensory domain). 6. Weber fractions in different modalities (p.124): Note that 2% change in brightness (millilamberts) is detectable in vision 10. Signal detection theory says "no" 0. Sensitivity vs. criterion 1. Hits & false alarms But are thresholds fixed? Discrimination vs. Criterion Applications of signal detection theory 0. The vigilance decrement 1. Police lineups 2. Jury decision making 3. Effects of brain damage on memory 4. In all cases, SDT allows us to ask: Does a factor affect discrimination or merely alter criterion? Transduction and coding in the different sensory systems 11. Hearing 12. Vision 13. Taste 14. Smell 15. Skin senses 16. The kinesthetic & vestibular senses 17. A point to remember: The senses work together 5. The acoustic signal The Auditory System 0. frequency --> pitch (p. 130) 1. amplitude --> loudness (p. 131) 2. complex sounds & timbre (pp. 133) 6. The outer ear The Ear (p. 133-4) 3. pinna, auditory canal 4. The tympanic membrane (ear drum) 5. hammer, anvil & stirrup 6. The oval window 7. The cochlea 7. The middle ear 8. The inner ear 0. The basilar membrane, organ of corti & hair cells Neural Pathways from Ear to Brain 18. Pitch perception Coding of Pitch 7. Frequency theory & the volley principle . . . Lower pitched sounds 8. Place theory (p. 135) . . . Higher pitched sounds 9. Duplicity theory . . . the synthesis 10. Representation of frequency in the auditory cortex 11. Absolute pitch: Linking pitch perception to labels 9. Perceiving location of sounds (p. 136) Locating sounds in space 8. Time differences for low frequency sounds 9. Intensity differences for high frequency sounds 10. Changes when turning head back and forth The Visual System 19.The electromagnetic spectrum & 12. visible light: 350-700nm 13. ROY G. BIV (p. 137) 20.The eye 14. Basic parts of the eye (p. 138) 15. Rods & cones (p. 138-9) 2. 3. Rods: Highly sensitive but achromatic and low acuity Cones: Less sensitive but chromatic and high acuity 16. bipolar & ganglion cells Adaptation and Contrast (pp. 140-144) 10. We are sensitive to change 11. We are sensititve to edges 12. Contrast effects: 11.Things look brighter if they are next to darker things . . . . and darker if they are next to brighter things 12.Lateral inhibition (p. 143) Color Vision 13. The Young-Helmholtz theory: Consistent with three types of cones 14. The opponent-process theory: Consistent with color contrast effects and afterimages 13.Ganglion cells with red/green & blue yellow opposition (p. 148) 15. "Color blindness:" Problems in seeing red, green, or blue (or combinations) Shape 16. Neurons in the visual system have distinct receptive fields (p. 150) 17. And some are feature detectors (p. 151) 18. In lower animals they can be on the retina 19. In higher animals they are in primary visual cortext and further "downstream" Detecting complex forms 20. Some single units appear like object detectors (e.g., faces, hands) 21. But objects are detected as combinations of features 14.Another case of the binding problem 22. Taste The Chemical Senses 15. Papallae containing taste buds 16. Sweet, sour, bitter & salty 21. Taste The Chemical Senses 17. Papallae containing taste buds 18. Sweet, sour, bitter & salty 19. Functions: Picking what to eat, tracking, communication 20. The olfactory epithelium 21. A short path to the limbic system: Odors and emotional memories 22. Smell The skin senses 23.Touch & pressure-- 22. corpuscular swellings 24.Temperature 23. Free nerve endings in skin 4. 5. cold and warm fibers in the skin detect decreases and increases in temperature The importance of adaptation level 25.Pain 24. intense stimulation & tissue damage 25. Effects of culture, social context & motivation The Kinesthetic & Vestibular Senses 23. Kinesthesis 17.Skeletal movements and positioning 18.Receptors in the muscle fibers & joints: movement, posture, orientation 24. The vestibular sense 19.Balance and equilibrium 20.The vestibular sacs & semicircular canals 21.Detection of head motion ...
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This note was uploaded on 04/09/2008 for the course PSY 2301 taught by Professor Holub during the Spring '08 term at University of Texas at Dallas, Richardson.

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