Forward-masking and pulsation thresholds were measured using both method-of-adjustment and two-alternative, forced-choice psychophysical procedures. The forced-choice pulsation-threshold procedure was similar to that described by DuMond and Stern [J. Acoust. Soc. Am. Suppl 1 65, S58(A), (1979)]. Signals and maskers were digitized sinusoids. Two sets of stimulus conditions were tested: 250-ms masker and 20-ms probe, and 125-ms masker and 125-ms probe. These conditions approximate those often reported for forward-masked and pulsation thresholds, respectively. Data were plotted as psychophysical tuning curves for evaluation. Differences in frequency selectivity measured across stimulus conditions and psychophysical procedures are the result of a combination of factors, including stimulus-ensemble characteristics and decision criteria. These stimulus and procedure variables must be taken into account when comparing estimates from different laboratories. [Research supported by PHS Grant No. RR-07096 awarded to the University of Washington.]