The detection of a brief (40 msec) 1000‐Hz sinusoid in the presence of narrow‐band noise was investigated using a rating‐scale procedure. Signals were added either to noise alone (simpledetection) or to noise plus sinusoidal pedestal (pedestaldetection). In the simple‐detection experiment, the noise masker was presented in one condition as a steady background and in another as a gated burst for a duration equal to the observation interval. In the pedestal‐detection experiment, the masker, consisting of noise plus pedestal, was gated on only during the observation interval. Receiver operating characteristics (ROC curves) were determined utilizing both a one‐interval and a two‐interval observation period. A comparison of performance measures estimated from ROC's for one‐ and two‐interval paradigms showed that detectability was superior for the two‐interval paradigm. The slopes of the ROC's for two‐interval detection were slightly larger than unity and were greater than those obtained in comparable one‐interval experiments.