The frequency principle for comparative judgments)

This experiment supplements a recetlf study of the effects of an interpolated weight upon memory for a standard (Parducci, Marshall, & Degner, 1966). The earlier data suggested that the stimulus-averaging approach as represented by the theory of adaptation level should be modified to incorporate the principle that Ss use alternative categories with equal frequency. The present data support this modification by demonstrating that even when the stimulus mean is held constant, judgments are affected by the relative frequencies of the comparison stimuli.