PSYC 212 Lecture Notes - Lecture 4: Absolute Threshold, Psychophysics, Detection Theory
13 Apr 2018
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Each jnd is abstract, but they are also perceptually equivalent so we know that each jnd is around the same size. Logarithmic shape: because of the weber fractions principle, it will take more and more physical stimulus intensity to produce one jnd. You need a larger difference in x to produce a change in y. Example q: if you vary physical stimulus intensity for 1 to 10. To produce a second jnd, you take 1/1. 5= 0. 75 1. 5 + 0. 75= 2. 25. This produces a logarithmic shape and mathematical function which tied into psychological introspection helped make psychology into more of a science. Different threshold= smallest diff you can perceive between two stimuli when you calculate jnd. Absolute threshold= smallest physical intensity you can perceive. Has a logistic s shape and the different thresholding techniques try to allow us to extract this logistic s function. Thresholding methods: what is the best way to quickly obtain the most accurate threshold.
