DETECTION OF UNEXPECTED TONES WITH SHORT AND LONG DURATIONS

The detectability of short and long unexpected tones masked by a conti nuous wideband noise was assessed using a probe-signal method. This me thod leads the listener to expect a target frequency by presenting the signal most often at that frequency, and only occasionally at other u nexpected probe frequencies. The probe-signal contour (percent correct as a function of probe frequency) was considerably broader with 5-ms than with 295-ms signals. However, auditory filter shapes measured usi ng the notched-noise technique were very similar for those two signal durations, indicating that the results obtained in the probe-signal co nditions do not simply reflect peripheral frequency selectivity Furthe r supporting this interpretation, probe tones having the same frequenc y but a different duration from the target were poorly detected. It is proposed that the subject listens through a time-frequency window who se location and shape in the time-frequency plane is determined by the duration and frequency of the target.