An adaptive tuning procedure for the psychophysical study of complex sounds

Abstract

Auditory object perception depends on the subjective criteria used by the observer to decompose an ambiguous acoustic field into auditory sources. Results from discrimination or detection experiments based on objective psychophysical procedures can only provide indirect evidence concerning the nature of the observer's source decomposition rules. Standard subjective psychophysical procedures provide direct evidence, but may be influenced by response bias and more importantly by experimenter bias in the choice of stimulus parameters to adjust. In the present paper, an adaptive tuning procedure is introduced which, unlike the method of adjustment, provides an efficient search over the stimulus space while minimizing experimenter bias in selecting that search space. The psychophysical procedure optimizes the stimulus parameter space according to a perceptual criterion adopted by the observer. It is claimed that inferences concerning the cues for source formation can be drawn from the values of the stimulus parameters to which the procedure converges. The procedure is applied to study the enhancement and degradation of single and multicomponent sinusoids in noise and to comodulated multicomponent sinusoids in noise to evaluate this claim. [Work supported by grants from the AFOSR (AFOSR‐87‐0193) and the NIH (NINDCD NS21440).]