Exploratory Studies of Zwicker's “Negative Afterimage” in Hearing

Abstract

This paper describes several exploratory experiments on a subjective tone that Zwicker discovered and referred to as the “negative afterimage.” Zwicker described the tone as audible upon cessation of a band‐rejected noise or band‐rejected pulse train stimulus, and as having a pitch corresponding to a frequency within the rejected band. We worked exclusively with noise stimuli. Our principal finding is that the minimum adequate stimulus appears to be a spectral edge rather than a rejected band, and that a low‐pass edge is more effective than a high‐pass edge. Other findings are as follows. Most people hear the tone, but susceptibility varies widely and the effect is labile. With favorable stimulus parameters, precision of matching to its pitch is on the order of 5% to 10% of the mean. The principal determinant of pitch is the location of the edge of the low‐pass component of the stimulus; the pitch corresponds to a frequency about 2 3 oct above that edge. Energy in the high‐pass component of the inducing stimulus enhances perception of the tone but has little effect on its pitch.