Abstract
The enhanced judgments of intensity of soft tones judged along with a series of bright lights (assimilation effect) was found to be dependent on the fact that the lights were judged coincidently. This dependence was not observed in a parallel investigation of contrast effects in the judgments of tones alone. Both the form of the assimilation effect and its specific dependence on judging both stimulus modalities argues against a sensory explanation. Instead, it is argued that this cross-modality assimilation effect represents a resolution of the specific difficulties involved in judging two qualitatively different modalities on one judgment scale