Some further tests of the constant-ratio rule

Five experiments sought to test the constant-ratio rule (CRR) with single dimensional ensembles composed of 2, 4, or 8 stimulus objects. Each S attempted to identify stimuli which varied in weight or in visual size or brightness. The results demonstrated: (a) The CRR predicts equally well the response proportions of single dimensional visual, kinesthetic, and auditory stimulus ensembles, but less well than those for multidimensional auditory stimuli. (b) Better predictions are obtained with four than with two stimulus objects.(c) The CRR is sensitive to variations in the spacing and range of the stimulus ensembles and to practice on the task. It is concluded that the rule tends to fail whenever stimulus conditions elicit differential amounts of stimulus and response confusion.