SCALING CONFIDENCE CATEGORIES: EQUAL SPACING?
On each trial in a psychophysical comparison experiment, participants used the confidence categories â€œ50â€, â€œ60â€, â€œ70â€, â€œ80â€, â€œ90â€, and â€œ100 to indicate how certain they were that they had made a correct decision. We applied Case D of Torgersonâ€™s (1958) Law of Categorical Judgment (LCJ) to estimate the mean locations of the confidence category boundaries. Scale values for the confidence category boundaries were equally spaced on the underlying subjective probability scale and were identical in the speed and the accuracy stress conditions of the experiment. Excellent goodness of fit of the LCJ to the data was obtained in each condition.