Mental Health Res. Inst., Univ. of Michigan, Ann Arbor, MI 48109-0720
Within-signal frequency discrimination for mixtures of two complex tones of different fundamental frequency (``modulation detection'') was examined under conditions of temporal asynchrony of the individual complex tones. Over a wide range of temporal conditions, the accuracy of discrimination of fundamental frequency: is primarily determined by the temporal overlap of the two complex tones; is independent of the duration of the leading complex tone preceding the mixture; and, is negatively related to the duration of the lagging complex tone following the mixture. The latter result suggests a form of retroactive interference (`backward masking') upon the processing of within-signal frequency differences for mixtures of complex tones.