Spectral and temporal models of human pitch perception with mixtures of three concurrent harmonic complexes

In music and other everyday situations, humans are often presented with three or more simultaneous pitches, each carried by a harmonic complex tone, but few empirical or theoretical studies have addressed how pitch is perceived in this context. In three behavioral experiments, mixtures of three concurrent complexes were filtered into a single bandpass spectral region, and the relationship between the fundamental frequencies and spectral region was varied in order to manipulate the extent to which harmonics were resolved either before or after mixing. Listeners were asked to discriminate major from minor chords (Experiment 1) or to compare the pitch of a probe tone to that of a target embedded in the mixture (Experiments 2 and 3). In all three experiments, listeners performed above chance even under conditions where traditional rate-place models would not predict individually resolved components. Human behavioral results were compared to predictions from two classes of pitch model: a rate-place model using harmonic template matching and a temporal model using summary autocorrelation. Predictions from a combined model, using both rate-place and temporal information, were more accurate than predictions from either model alone, suggesting that humans may integrate these two kinds of information. [Work supported by NIH grant R01DC005216.]