PSYC 213 Chapter 1: chapter 1 notes
30 Jul 2015
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Sensation begins when the stimulus intensity triggers sensation. Method of adjustment: observer adjusts stimuli until you reach threshold. Method of limits: changing intensity of stimulus (reduced anticipation/expectation factor) until stimulus is perceived/no longer perceived. Method of constant stimuli: choose fixed range, changes stimuli with range, observer says whether stimulus is perceived or not most accurate, less expectation/anticipation factor, a lot of trials so less attention. No unlimited range because not ethical because pain. Because so many trials are needed, one can"t sample everything so you need a fixed range. Need 20 minimum trials per stimulus + 100-200 trials total. Even if long person takes breaks so they don"t answer erratically. Threshold function is a linear ogive like function because lots of noise in system, expectation (criterion), sensory system, subject error. Absolute threshold the point where a stimulus is perceived. Absolute threshold level to which you can hear something mainly statistical to prevent chance.
