Psych Review Ch4

Psych Review Ch4 - Chapter 4: Sensation and Perception 1....

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Chapter 4: Sensation and Perception 1. Explain how stimulus intensity is related to absolute thresholds. Sensation is the stimulation of sense organs. Perceptions is the selection, organization, and interpretation of sensory input. A threshold is a dividing point between energy levels that do and do not have a detectable effect. An absolute threshold for a specific type of sensory input is the minimum stimulus intensity that an organism can detect. Researchers define the absolute threshold as the stimulus intensity that is only detected 50% of the time. 2. Describe the JND and explain Weber’s law. A just noticeable difference is the smallest difference in stimulus intensity that a specific sense can detect. Webster’s law states that the size of a JND is a constant proportion of the size of the initial stimulus. 3. Explain the basic thrust of signal-detection theory. Signal detection theory proposes that the detection of a stimulus involves decision processes as well as sensory processes, which are both influenced by a variety of factors besides stimulus intensity. Hits are detecting signal when they are present, Misses are missing signals when they are present, False Alarms are detecting signals when they are not present, and Correct Rejections are not detecting signals when they are not present. The more “noise” in a system, the harder it will be to pick up a weak signal. Signal detection theory is better equipped to explain some of the complexities of perceived experiences in the real world. 4. Summarize evidence on perception without awareness and discuss the practical implications of subliminal perception. Subliminal perception is the registration of sensory input without conscious awareness. Many studies have shown this to be plausible, but the effects of subliminal stimuli turn out to be nearly as subliminal as the stimuli themselves. Many companies place subliminal messages in advertisements in hopes of drawing in customers to their product. Muller’s Doctrine of Specific Nerve Energies says that different sensations are experienced because different areas of the brain are stimulated. 5. Discuss the meaning and significance of sensory adaptation. Sensory adaptation is a gradual decline in sensitivity to prolonged stimulation. Sensitivity to a stable odor decreases as you experience it. Sensory adaptation is an automatic, built-in process that keeps people tuned in to the changes rather than the constants in their sensory input. There is no one-to-one correspondence between sensory input and sensory experience. Cocktail Party Phenomenon is sensing without perceiving, selective attention, tuning into the conversation you are having and tuning out other conversations around you, or tuning into hearing your name. 6. List the three properties of light and the aspects of visual perception that they influence.
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This note was uploaded on 04/29/2008 for the course PSYCH 201 taught by Professor Raymark during the Spring '08 term at Clemson.

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Psych Review Ch4 - Chapter 4: Sensation and Perception 1....

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