Extension of the Theory of Signal Detectability to Matching Procedures in Psychoacoustics

The theory of signal detectability is used to analyze experiments where the observer's task is to state, after two signal presentations, whether the signals were the same or different. A model is suggested for predicting human performance in auditory “matching” tasks using data from detection and discrimination experiments. Three experiments are discussed which lend support to the model's application. The first, a two-alternative forced-choice, pulsed-carrier experiment, serves to determine each observer's efficiency. The efficiency η is assumed constant provided certain observation interval and signal characteristics are held fixed, as they were during the entire experimental sequence. The second was a simple matching task, where the first observation interval always contained specified signal and the second sometimes contained a signal identical to the first. In the third experiment the signal appearing in the first interval was randomly chosen from a set of possible signals, thus removing the long-term memory requirement, and necessitating a comparison observation based on both intervals. The results are consistent with the assumption of constant efficiency across different tasks, and close agreement with the model's predictions for matching performance is demonstrated. Also discussed are stone interesting side issues raised by the experimental data which are relevant to current use of the matching procedure in other areas of psychology. Consideration is made of possible further applications of the matching procedure, such as in determining the value of Θ in recognition experiments.