Abstract:
The decision strategy adopted by an observer in a psychophysical procedure may be established by comparing estimates of sensitivity obtained by using detection-theoretic models based on each of the available decision strategies. Estimates of sensitivity obtained from 10 observers on auditory-level discrimination tasks using the yes/no, two-alternative forced choice (2AFC), and 2AFC with reminder (2AFCR; sometimes called duo–trio) procedures were compared in order to determine the decision strategy used by the judges in the 2AFCR procedure. 2AFCR permits at least three decision strategies: differencing, likelihood ratio, and comparison of distances. The latter strategy has frequently been assumed in the analysis of duo–trio data in the sensory evaluation literature. The present study demonstrates that the comparison-of-distances strategy was not used by 9 of the 10 observers in this auditory experiment. The nature of the instructions given to the observers had no measurable impact on the decision strategy that they adopted.
