Perceptual independence of pitch and loudness in a signal detection experiment: A processing model for 2ATFC (21FC) experiments

Abstract

The two-alternative temporal forced choice (2ATFC) experiment is used to measure the relative detectabilities of a frequency change, an amplitude increase, or both together. Subjects’ performance is best when both (redundant) cues are available. This improvement is fit better by a decision threshold model than by an information integration model. Since decision processes that can lead to the decision threshold prediction in (2ATFC) experiments are not obvious, an information processing model which does is proposed. The model makes additional predictions which fit the results of an experiment which sometimes deletes information from the first or the second observation interval. The model is not consistent with the signal detection theory interpretation of the 2ATFC experiment, and these results call into question that interpretation. It is concluded that pitch and loudness are perceptually independent for the 2ATFC experiment.