1. Ch. 3 - Sensation and Perception Sensation - The experience of sensory stimulation Perception - The process of creating meaningful patterns from raw sensory information

2. 1.The Nature of Sensory Processes A.The Basic Process Receptor Cell- A specialized cell that responds to a particular type of energy B.Sensory Thresholds Absolute The least amount of energy that can be detected 50% of the time Adaptation An adjustment of the senses to the level of stimulation

3. Sensory Thresholds

4. Difference The smallest change in stimulation that can be detected 50 % of the time Subliminal perception Below our level of awareness Extrasensory perception Extraordinary perception such as sensing the future

5. 2.Vision A.The Visual System Cornea transparent protective coating over the front of the eye Pupil small opening in the iris through which light enters the eye Iris colored part of the eye

6. Lens transparent structure inside the pupil that focuses light onto the retina Retina lining of the eye containing receptor cells that are sensitive to light Retina Movie

7. The Visual System Visual System Movie #1 Visual System Movie #1 Visual System Movie #2 Visual System Movie #2 Visual System Movie #3 Visual System Movie #3

8. Receptor cells Wavelengths - different energies represented in the electromagnetic spectrum Rods - receptor cells in the retina for night vision Cones - receptor cells in the retina responsible for color vision. Bipolar Cells - connect receptors to ganglion Fovea / visual acuity - area of the retina with the sharpest vision Retina / Fovea Movie

9. Cones respond to light and dark as well as to color or different wavelengths of light

10. Adaptation Dark Increased sensitivity of rods and cones in darkness Light Decreased sensitivity of rods and cones in bright light Afterimage Sense experience that occurs after a visual stimulus has been removed

11. Eye to brain Neurons that connect the bipolar cells in the eyes to the brain Optic nerve are bundle of axons of ganglion cells that carries neural messages from each eye Blind spot place where the axons of all the cells leave the retina (no receptors)

12. The bipolar cells connect to ganglion cells, whose axons converge to form the optic nerve that carries messages to the brain

13. B. Color Vision Properties of color Hues – Colors such as red and green Saturation - Vividness of a hue Brightness - Nearness of a color to white

14. Theories of color vision Subtractive color Mixing pigments Additive color mixing Lights, T.V., monitor (RGB)

15. Trichromatic theory (Helmholtz) Colorblindness (Tri-,Di-, and Monochromats) 3 different receptors (RGB) People inherit receptors which respond differently

16. Opponent-process theory (Hering) Three sets of color receptors Yellow-blue, red-green, black-white Either/or response C.Color Vision in Other Species

17. The opponent-process theory maintains that receptors are specialized to respond to either member of the three basic color pairs: red-green, yellow-blue, and black-white (dark and light)

19. 3. Hearing A. Sound Sound waves Changes in pressure caused by molecules of air moving Frequency Number of cycles per second in a wave; pitch Hertz Cycles per second; frequency

20. Pitch Frequency of vibrations, results in tone Amplitude Magnitude; loudness Decibels Measurement of loudness Overtones - Multiples of the basic tone Timbre - Quality of texture of sound

21. Amplitude is the magnitude of a wave; it largely determines the loudness of a sound. Loudness is measured in decibels

22. B.The Ear Hammer, anvil, stirrup 3 small bones in the middle ear that relay vibrations Oval window Membrane between middle ear and inner ear

23. Hearing begins when sound waves strike the eardrum and cause it to vibrate. This vibration, in turn, makes three bones in the middle ear—the hammer, the anvil, and the stirrup—vibrate in sequence

24. Cochlea Part of inner ear containing fluid that vibrates and then causes the basilar membrane to vibrate Basilar membrane Vibrating membrane in the cochlea which contains receptor cells Neural connections Auditory nerve Connection from ear to brain Bilateral

25. Inside the organ of Corti are tiny hair cells that act as sensory receptors for hearing. Stimulation of these receptors produces auditory signals that are transmitted to the brain through the auditory nerve. The brain pools the information from thousands of these cells to create the perception of sounds

26. C. Theories of Hearing Place theory Pitch is determined by location of vibration Frequency theory Pitch is determined by frequency hair cells fire Volley Principle Pattern of sequential firing determines pitch

27. Hearing disorders Damaged eardrum Damaged middle ear bones Damaged nerves Loud music, tools, etc Tinnitus 1% of population

28. 4.The Other Senses A.Smell Detecting common odors Communicating with pheromones B.Taste Receptor cells in taste buds

29. The sense of smell is activated by substances carried by airborne molecules into the nasal cavities, where the substances activate highly specialized receptors for smell, located in the olfactory epithelium

30. The receptor cells for the sense of taste are housed in the taste buds on the tongue, which, in turn, are found in the papillae, the small bumps on the surface of the tongue

31. C. Kinesthetic and Vestibular Senses Stretch receptors Sense muscle stretch and contraction Golgi tendon organs (injections) Sense movement of tendons Vestibular senses Senses of equilibrium and body position

32. D. Sensations of Motion Vestibular organs are also responsible for motion sickness May be caused by discrepancies between visual information and vestibular sensation E.The Skin Senses Skin receptors for pressure, temperature, and pain Importance of touch

33. F.Pain Individual differences Gate control theory Gate in spinal cord which controls transmission of pain to brain Biopsychosocial theory The Placebo Effect Alternative approaches

34. 5.Perception A.Perceptual Organization B.Perceptual Constancies Size constancy Shape constancy Brightness constancy Color constancy

35. Perceptual Organization

36. Perceptual constancy is our tendency to perceive objects as unchanging in the face of changes in sensory stimulation. Once we have formed a stable perception of an object, we can recognize it from almost any angle

37. C.Perception of Distance and Depth Moon Movie D.Perception of Movement E.Visual Illusions

38. When we use sensory information to create perceptions, we fill in the missing information, group various objects together, see whole objects, and hear meaningful sounds

39. Visual illusions occur when we use a variety of sensory cues to create perceptual experiences that do not actually exist

40. F.Observer Characteristics: Individual Differences and Culture Motivation Value Expectation Cognitive Style Experience and Culture Personality

41. Superposition is a monocular distance cue in which one object, by partly blocking a second, appears closer

42. Linear perspective is another monocular cue to distance and depth based on the fact that two parallel lines seem to come together at the horizon