5.29  method of constant stimuli; method of right and wrong cases. Test method whereby a subject responds to each presentation of a stimulus: “yes-no,” “same-different,” “greater than-equal to-less than.” Stimuli, ranging from rarely to almost always perceivable (or rarely to almost always perceivably different from some reference stimulus), are presented one at a time. Used primarily to determine thresholds.

Annotation         A special case of the method of constant stimuli is the quantal method; here, fixed increments are added to a reference stimulus and the subject reports whether or not the increment is perceived.

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