Small-sample characterization of stochastic approximation staircases in forced-choice adaptive threshold estimation.

Despite the wide spread use of up–down staircases in adaptive threshold estimation, their efficiency and usability inforced-choice experiments has been recently debated. In this study, simulation techniques were used to determine the small-sample convergence properties of stochastic approximation (SA) staircases as a function of several experimental parameters. We found that satisfying some general requirements (use of the accelerated SA algorithm, clear suprathreshold initial stimulus intensity, large initial step size) the convergence was accurate independently of the spread of the underlying psychometric function. SA stair cases were also reliable for targeting percent-correct levels far from the midpoint of the psychometric function and performed better than classical up–down stair cases with fixed step size. These results prompt the utilization of SA stair cases in practical forced-choice estimation of sensory thresholds. [ABSTRACT FROM AUTHOR]