Towards a Vocal Constraints Model of Melodic Expectancy: Evidence from Two Listening Experiments

Where does a listener's anticipation of the next note in an unfamiliar melody come from? One view is that expectancies reflect innate grouping biases; another is that expectancies reflect statistical learning through previous musical exposure. Listening experiments support both views but in limited contexts, e.g., using only instrumental renditions of melodies. Here we report replications of two previous experiments, but with additional manipulations of timbre (instrumental vs. sung renditions) and register (modal vs. upper). Following a proposal that melodic expectancy is vocally constrained, we predicted that sung renditions would encourage an expectation that the next tone will be a “singable” one, operationalized here as one having an absolute pitch height that falls within the modal register. Listeners heard melodic fragments and gave goodness-of-fit ratings on the final tone (Experiment 1) or rated how certain they were about what the next note would be (Experiment 2). Ratings in the instrumental conditions were consistent with the original findings, but differed significantly from ratings in the sung conditions, which were more consistent with the vocal constraints model. We discuss how a vocal constraints model could be extended to include expectations about duration and tonality.