Abstract
Musical expectancy theory posits that listeners anticipate both the pitch that will occur and when it will occur; however, the interaction between these dimensions across age and expertise is less understood. In this study, 175 adults (ages 18–82; musicians and non-musicians) rated the final note of short monophonic melodies on its melodic and temporal fit. Endings were systematically manipulated in terms of pitch (tonal, chromatic, or atonal) and timing deviations. Results showed a strong effect of melodic expectancy: pitch deviations substantially reduced goodness-of-fit ratings, whereas timing shifts had comparatively weak effects. Musicians gave lower ratings overall, indicating heightened sensitivity to expectancy violations, whereas non-musicians were more lenient. Although age alone did not predict ratings, an age × musician interaction emerged: older musicians diverged most strongly from older non-musician peers, suggesting that expertise sharpens expectancy sensitivity across the lifespan. These findings demonstrate that pitch dominates expectancy judgments, while also revealing how aging and musicianship jointly influence the perception of musical errors—an area that remains underexplored in music cognition.