Textbook Notes (363,381)
Canada (158,358)
Psychology (1,867)
PSY100Y5 (787)
Dax Urbszat (659)
Chapter 4

textbook notes chapter 4

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University of Toronto Mississauga
Dax Urbszat

Nov12003 CHANAPS Notes From Reading C HAPTER 4: SENSATION AND PERCEPTION Chapter 4 Sensation and Perception Visual agnosia- an inability to recognized objects through sight Sensation- the stimulation of sense organs Perception- the selection, organization, and interpretation of sensory input Psychophysics: Basic concepts and Issues - Psychophysics is the study of how physical stimuli are translated into psychological experience. - Gustav Fechner was an important contributor to psychophysics in 1860 Threshold: Looking For Limits - For any given sense what is the weakest detectable stimulus? (what is the minimal amount of light needed to detect that there is light) - 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 amount of stimulation that an organism can detect. Weighing the Differences: The JND - A just noticeable difference (JND) is the smallest difference in the amount of stimulation that a specific sense can detect. - Webers law states that the size of a just noticeable difference is a constant proportion of the size in the initial stimulus. - As stimuli increases in magnitude JND becomes larger. Psychophysical Scaling - Fechners law, which states that the magnitude of a sensory experience is proportional to the number of JNDs that the stimulus causing the experience is above absolute threshold. - Three equal increases in stimulus intensity produce progressively smaller differences in the magnitude of sensation. - Peoples inner measurements of sensory experiences are not a simple linear function of the physical intensity of the stimuli Signal-Detection Theory 112 www.notesolution.comNov12003 CHANAPS Notes From Reading C HAPTER 4: SENSATION AND PERCEPTION - Signal detection theory proposes that the detection of stimuli involves decision processes as well as sensory processes, which are both influenced by a variety of factors besides stimulus intensity. - Hits are detecting signals when they are present - Misses are failing to detect signals when they are present - False Alarms are detecting signals when they are not present - Correct rejections are not detecting signals when they are absent - Performance will depend on the level of noise in the system - The more noise in the system, the harder it will be for you to pick up a weak signal Perception Without Awareness - Subliminal perception is the registration of sensory input without conscious awareness - Sexual words and drawings are embedded subliminally in magazine advertisements to elicit favorable unconscious reactions from consumers - Perception without awareness can take place - No evidence that subliminal stimuli can lead people to buy specific products, abandon their sexual inhibitions, become Satan worshippers, or improve themselves - Research has not bolstered the idea that persuasive efforts operating beneath the surface of conscious awareness are especially powerful. Sensory Adaptation - Sensory adaptation is a gradual decline in sensitivity to prolonged stimulation. - Sensory adaptation is an automatic, built-in process that keeps people tuned into the changes rather than the constants in their sensory input - Example would be, Smelling Garbage in the kitchen once you first enter it, after a while the smell is still stable but with continued exposure, your sensitivity to it decreases - Sensory adaptation is probably behavioral adaptation that has been sculpted by natural selection - Peoples experience of the world depends on both the physical stimuli they encounter and their active processing of stimulus inputs. Our Sense of Sight: The Visual System The Stimulus: Light - Light is a form of electromagnetic radiation that travels as a wave, moving naturally enough, at the speed of light. 212 www.notesolution.com
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