Probability of alternate perceptual responses is suggested as an approximate quantitative index of "goodness" of figure, and a group technique is presented by which this score can be obtained for ambiguous stimuli. Using the technique to obtain group scores for relative duration of tri- and bidimensional phases of 4 Kopfermann cube fugures, the resulting responses are not inconsistent with the working hypothesis, namely that the probability of a given perceptual response to a stimulus is an inverse function of the amt. of information required to define that pattern.