Experience with a yes-no single-interval maximum-likelihood procedure

The report in 1993 by Green [J. Acoust. Soc. Am. 93, 2096-2105 (1993)] desc ribing the application of a new psychophysical method requiring few trials and little time to measure auditory thresholds has generated considerable i nterest among experimentalists. The procedure uses a single-interval stimul us presentation, requests a yes-no decision by subjects, and implements a m aximum-likelihood calculation to determine the next trial stimulus level wi thin an adaptive track, as well as the final threshold estimate. Data are p resented here describing separate experiences with this procedure in two la boratories in both detection and discrimination tasks. Issues addressed inc lude comparisons with more traditional psychophysical methods, variability in threshold estimates, experimental time required, and possible minor modi fications to improve the basic procedure. Results using this procedure are comparable in terms of variability of estimates to those emerging from more lengthy procedures. However, because it may be difficult for some listener s to maintain a consistent criterion and because attentional lapses may be costly, experimenters must be willing to monitor performance closely and re peat some tracks in cases where excessively high variability is noted. Furt her, this procedure may not be suitable for tasks for which the form of the psychometric function is not well-established. Modifications allowing a va riable slope parameter in the maximum-likelihood evaluations of psychometri c functions may be of benefit. (C) 2000 Acoustical Society of America. [S00 1-4966(00)03305-1].