Independence in the perception of complex non-speech sounds

Abstract

Little, if any, work has explicitly addressed independence in the perception of complex sounds. General recognition theory provides a powerful framework in which to address such issues. Two experiments were carried out to test within‐stimulus, between‐stimulus, and decision‐related notions of independence in each of two stimulus sets. One set consisted of broadband noise stimuli varying in frequency and duration, the other set consisted of harmonic tone complexes varying in fundamental frequency and spectral shape. Model fitting analyses indicate that decision‐related independence (decisional separability) holds for all participants with the noise stimuli and the majority of participants with the harmonic stimuli, that within‐stimulus independence (perceptual independence) holds for all participants with the noise stimuli and between‐stimuli independence (perceptual separability) holds for all but two participants with the noise stimuli, whereas considerable individual differences are exhibited in a variety of failures of either perceptual independence or perceptual separability or, occasionally, both, for participants with the harmonic stimuli. The noise stimulus results are consistent with expectations based on models of frequency and duration encoding, whereas the harmonic stimulus results present a challenge to a number of models of pitch and timbre encoding. [This work was supported by NIH Grant No. T32 MH019879‐13.]