Figure 1.

Schematic depicting spectral and temporal characteristics of the precursor, masker and signal in Expt. 1. Panels (a) and (b) show off-frequency and on-frequency precursor conditions, respectively. Highpass noise (not shown) also was present in all conditions; it began 50 ms before the precursor and ended 50 ms after signal offset. The spectrum level of the noise varied with signal level, but always was 50 dB below the signal level, and had lower and upper cutoff frequencies of 4.8 and 8.0 kHz, respectively.