Systematic errors in the perception of rhythm

Abstract

One hypothesis for why humans enjoy musical rhythms relates to their prediction of when each beat should occur. The ability to predict the timing of an event is important from an evolutionary perspective. Therefore, our brains have evolved internal mechanisms for processing the progression of time. However, due to inherent noise in neural signals, this prediction is not always accurate. Theoretical considerations of optimal estimates suggest the occurrence of certain systematic errors made by the brain when estimating the timing of beats in rhythms. Here, we tested psychophysically whether these systematic errors exist and if so, how they depend on stimulus parameters. Our experimental data revealed two main types of systematic errors. First, observers perceived the time of the last beat of a rhythmic pattern as happening earlier than actual when the inter-beat interval was short. Second, the perceived time of the last beat was later than the actual when the inter-beat interval was long. The magnitude of these systematic errors fell as the number of beats increased. However, with many beats, the errors due to long inter-beat intervals became more apparent. We propose a Bayesian model for these systematic errors. The model fits these data well, allowing us to offer possible explanations for how these errors occurred. For instance, neural processes possibly contributing to the errors include noisy and temporally asymmetric impulse responses, priors preferring certain time intervals, and better-early-than-late loss functions. We finish this article with brief discussions of both the implications of systematic errors for the appreciation of rhythm and the possible compensation by the brain’s motor system during a musical performance.

Relationships between the expectations based on the regularity of preceding sound sequences and the medial olivocochlear reflex

“…It would be possible that more than three bursts elicit stronger MOCR because an increase of the number of preceding tone bursts may improve the accuracy of the prediction on the timing of the MOCR elicitor arrival. Mansuri et al (2022) reported that accuracy of rhythm perception was higher as the number of beats increased [ 44 ]. Considering that Mansuri et al (2022) varied the number of beats form 3 to 8, it is reasonable to suppose that more preceding tone bursts would drive larger enhancement of MOCR, although the number of preceding tone bursts in the present study was limited to less than three.…”