Chapter5NarrativeSummary - C HAPTER 5 (SUMMARY): SENSATION...

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CHAPTER 5 (SUMMARY): SENSATION Overview Sensation is concerned with how the outside world gets represented inside our heads, and we are exquisitely sensitive to some of the stimuli around us. Research reveals that we process some information from subliminal stimuli, but only under certain restricted conditions. The task of each sense is to receive stimulus energy, transduce it into neural signals, and send those neural messages to the brain. In vision, light waves are converted into neural impulses by the retina; after being coded, these impulses travel up the optic nerve to the brain’s cortex, where they are interpreted. The Young-Helmholtz and opponent-process theories together help explain color vision. In hearing, sound waves are transmitted to the fluid-filled cochlea, where they are converted to neural messages and sent to the brain. Together, the place and frequency theories explain how we hear both high-pitched and low-pitched sounds. The sense of touch is actually four senses—pressure, warmth, cold, and pain—that combine to produce other sensations such as “hot.” Taste, a chemical sense, is a composite of sweet, sour, salty, bitter, and umami sensations, and of the aromas that interact with information from the taste buds. Smell, also a chemical sense, does not have basic sensations as there are for touch and taste. Our effective functioning also requires a kinesthetic sense and a vestibular sense, which together enable us to detect body position and movement. Sensing the World: Some Basic Principles Sensation versus perception. Sensation is the process by which we detect physical energy from our environment and encode it as neural signals; it involves what psychologists call bottom-up processing. Perception is the process of selecting, organizing, and interpreting sensory information, enabling us to recognize meaningful objects and events; it involves top-down processing. Absolute versus difference thresholds; research findings on subliminal stimulation. In studying the relationship between physical energy and psychological experience, researchers in psychophysics identified an absolute threshold as the minimum stimulation needed to detect a particular stimulus 50 percent of the time. Signal detection theory predicts when and how we detect the presence of a faint stimulus, assuming that our individual absolute thresholds vary with our psychological state. Recent research reveals that we can process some information from stimuli too weak to recognize. But the restricted conditions under which this occurs would not enable advertisers to exploit us with subliminal messages. A difference threshold is the minimum difference between two stimuli that a person can detect 50
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This note was uploaded on 02/14/2010 for the course PSY 101 taught by Professor Jackson during the Spring '08 term at Michigan State University.

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Chapter5NarrativeSummary - C HAPTER 5 (SUMMARY): SENSATION...

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