PSY 368 Lecture Notes - Lecture 6: Threshold Of Pain, False Alarm, Detection Theory
20 Sep 2017
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Document Summary
Predicts a step psychometric function: psychometric function relates stim intensity (x axis) to subject"s detection rate (y axis) Subj never report detecting stim at intensities below the absolute threshold, subj always report detecting the stim at intensities above the absolute threshold. These are theoretically ideal data, the data from real experiments are never this clean. Problems w/ classical threshold theory: relatively minor changes in how the task is worded greatly affect the psychometric function, absolute detection thresholds are infl by a person"s bias. Some ppl are reluctant to answer y (conservative bias), other people require relatively little evidence before answering y (liberal bias) Uses mathematical analysis of errors to separate decision factors from perceptual sensitivity. Mixes signal-present w/ signal-absent catch" trials: right and wrong answers can figure out bias a bit more easily compared to classical threshold theory. Signal = ativity in perceptual syst related to stim that you are trying to detect.
