Temporal integration and the microstructure of the detection threshold curve

Abstract

The detectability of sinusoids as a function of duration was measured for tones having durations of 10, 20, 40, 80, 160, and 320 ms and rise/fall times of 4 or 10 ms. Frequencies were selected to correspond to the peaks and valleys of each subject's detection threshold curve between 1000 and 1400 Hz [Cohen, J. Acoust. Soc. Am. Suppl. 1 65, S55(A) (1979)]. Results indicate that the threshold elevation which accompanies shorter duration is substantially larger for tones at those frequencies having a lower detection threshold level for a 350‐ms tone (valleys) than it is for tones at those frequencies having a higher detection threshold level (peaks). This is explained in terms of the spread of energy which accompanies the shortening of duration. This energy spread would be expected to differentially affect detection threshold levels for peaks and for valleys. [Work supported by the University of Connecticut Research Foundation.]