When stop consonant-vowel syllables, 390 msec in duration, are presented dichotically, with an onset asynchrony of 50–70 msec, subjects identify the temporally lagging stop more accurately than the leading. When the same pairs are presented monotically, the leading stop has the advantage. This difference has been interpreted in terms of central versus peripheral masking [M. Studdert-Kennedy, D. Shankweiler, and S. Schulman, J. Acoust. Soc. Amer. 48, 599–602 (1970)]. Dichotically, the signals travel separate peripheral pathways, and central masking effects are revealed. Monotically, the lagging signal is masked peripherally by the overlapping leading signal. This experiment was designed to determine the effect that the elimination of the temporal overlap would have on the dichotic and monotic masking functions. Syllables 75 msec long were presented at six asynchronies between 0 and 100 msec. The dichotic masking function was unaffected, whereas the monotic lead advantages were substantially reduced at the nonoverlapping asynchronies. Implications of these results will be discussed. [Work supported by NIH.]