Hp. Dai et al., DECISION RULES OF LISTENERS IN SPECTRAL-SHAPE DISCRIMINATION WITH OR WITHOUT SIGNAL-FREQUENCY UNCERTAINTY, The Journal of the Acoustical Society of America, 99(4), 1996, pp. 2298-2306
A correlation technique was used to assess the decision rules of three
listeners in two cases of spectral-shape discrimination tasks. fn one
case the signal frequency was fixed, and in the other it was randomly
varied within each block of trials. In order to estimate the decision
rule of the listeners, the experimenter superimposed random level per
turbations on each frequency component upon each stimulus presentation
. Over many trials, correlation coefficients were computed between the
random perturbations and the binary responses of the listeners, and w
ere expressed as a function of signal level. For both the fixed- and r
andom-signal cases, the measured correlation functions were in reasona
bly good agreement with those predicted based on the likelihood-ratio
decision rules. Thus the listeners appeared to use information nearly
optimally in discriminating spectral shapes. This investigation demons
trated that the correlation technique can be used to reveal the decisi
on rules for cases where the decision statistics are nonlinear functio
ns of the observations. (C) 1996 Acoustical Society of America.