Backward masking and interference within the same psychophysical continuum

Abstract

A number of attempts have been made to compare temporal masking, a threshold phenomenon, and the interference in the recognition or discrimination of a clearly detectable signal by another, temporally discrete, signal. Typically, traditional backward and/or forward masking functions are compared with functions relating frequency discriminations of pure tones which are preceeded or followed by another, interference, stimulus [cf., Sparks, J. Acoust. Soc. Am. 60, 1347 (1976)]. One notable feature of these studies involves the comparison of metathetic frequency discrimination tasks with prothetic intensity detection tasks. The present research was designed to compare backward masking and backward interference more directly, using detection and discrimination tasks within the same stimulus continuum. Backward masking functions were obtained using a 50‐ms broadband noise signal followed in time by another 50‐ms noise masker. Backward interference functions were obtained also using 50‐ms noise signals and 50‐ms noise maskers, in which the observer's task was to indicate which of two intervals contained the louder signal. The results are discussed in terms of threshold and suprathreshold intensity discriminations in the presence of temporal maskers.