Relationships among Assumptions of the Method of Limits and the Method of Constant Stimuli.

摘要

The phi-gamma hypothesis is a special case of the general hypothesis of a cumulative symmetrical distribution. Assuming any cumulative symmetrical distribution (a) the descending method of limits (DML) threshold distribution is asymmetrical and is a mirror image of the ascending method of limits (AML) distribution; (b) the combined method of limits (CML) distributions is symmetrical; (c) with the subscripts A, D, and C referring to AML, DML, and CML distributions: M sub A < M sub C < M sub D; sigma sub A = sigma sub D; sigma sub C > sigma sub A; (d) as step size increases: M sub A increases, M sub D decreases, M sub C remains constant, sigma sub A and sigma sub D increase, sigma sub C first decreases and then increases; (e) the mean threshold of the method of constant stimuli equals M sub C. These and other predictions are supported experimentally. (Author)