Psychophysical suppression of selective portions of pulsation threshold patterns.

Pulsation threshold patterns are measured for single tones and two-tone combinations. It is demonstrated that one tone can selectively suppress part of the pattern of another tone. This result supports the view that suppression takes the form of a distributed attenuation. Suppression does not function as if the suppressed tone is attenuated in level. When one tone suppresses another higher in frequency, the suppression is not as selective. In this case the entire pattern of the suppressed tone is reduced, but the reduction is not uniform across frequency. Mutual suppression, in which a reduction is seen in the patterns of both tones, is observed for one subject.