Peter M. C. Harrison’s research while affiliated with University of Cambridge and other places

Coordination between participants is a necessary foundation for successful human interaction. This is especially true in group musical performances, where action must often be temporally coordinated between the members of an ensemble for their performance to be effective. Networked mediation can disrupt this coordination process by introducing a delay between when a musical sound is produced and when it is received. This can result in significant deteriorations in synchrony and stability between performers. Here we show that five duos of professional jazz musicians adopt diverse strategies when confronted by the difficulties of coordinating performances over a network—difficulties that are not exclusive to networked performance but are also present in other situations (such as when coordinating performances over large physical spaces). What appear to be two alternatives involve: 1) one musician being led by the other, tracking the timings of the leader’s performance; or 2) both musicians accommodating to each other, mutually adapting their timing. During networked performance, these two strategies favor different sides of the trade-off between, respectively, tempo synchrony and stability; in the absence of delay, both achieve similar outcomes. Our research highlights how remoteness presents new complexities and challenges to successful interaction.

Recent advances in automatic music transcription have facilitated the creation of large databases of symbolic transcriptions of improvised music forms including jazz, where traditional notated scores are not normally available. In conjunction with music source separation models that enable audio to be “demixed” into separate signals for multiple instrument classes, these algorithms can also be applied to generate annotations for every musician in a performance. This can enable the analysis of interesting performer-level and ensemble-level features that have often been difficult to explore. To this end, we introduce Jazz Trio Database (JTD), a dataset of 44.5 h of jazz piano solos accompanied by bass and drums, with automatically generated annotations for each performer. These annotations consist of onset, beat, and downbeat timestamps, alongside MIDI for the piano soloist. Suitable recordings, broadly representative of the “straight-ahead” jazz style, were identified by scraping user-based listening and discographic data; source separation models were applied to isolate audio for each performer in the trio; annotations were generated by applying appropriate algorithms to both the separated and the mixed audio sources. Onset annotations generated by the pipeline achieved a mean F-measure of 0.94 when compared with ground truth annotations. We conduct several analyses of JTD, including with relation to swing and inter-performer synchronization. We anticipate that JTD will be useful in a variety of music information–retrieval tasks, including artist identification and expressive performance modeling. We have made JTD, including the annotations and associated source code, available at https://github.com/HuwCheston/Jazz-Trio-Database

Aesthetic preference is intricately linked to learning and creativity. Previous studies have largely examined the perception of novelty in terms of pleasantness and the generation of novelty via creativity separately. The current study examines the connection between perception and generation of novelty in music; specifically, we investigated how pleasantness judgements and brain responses to musical notes of varying probability (estimated by a computational model of auditory expectation) are linked to learning and creativity. To facilitate learning de novo, 40 non-musicians were trained on an unfamiliar artificial music grammar. After learning, participants evaluated the pleasantness of the final notes of melodies, which varied in probability, while their EEG was recorded. They also composed their own musical pieces using the learned grammar which were subsequently assessed by experts. As expected, there was an inverted U-shaped relationship between liking and probability: participants were more likely to rate the notes with intermediate probabilities as pleasant. Further, intermediate probability notes elicited larger N100 and P200 at posterior and frontal sites, respectively, associated with prediction error processing. Crucially, individuals who produced less creative compositions preferred higher probability notes, whereas individuals who composed more creative pieces preferred notes with intermediate probability. Finally, evoked brain responses to note probability were relatively independent of learning and creativity, suggesting that these higher-level processes are not mediated by brain responses related to performance monitoring. Overall, our findings shed light on the relationship between perception and generation of novelty, offering new insights into aesthetic preference and its neural correlates.

Previous psychological studies have shown that musical consonance is not only determined by the frequency ratios between tones, but also by the frequency spectra of those tones. However, these prior studies used artificial tones, specifically tones built from a small number of pure tones, which do not match the acoustic complexity of real musical instruments. The present experiment therefore investigates tones recorded from a real musical instrument, the Westerkerk Carillon, conducting a “dense rating” experiment where participants (N = 113) rated musical intervals drawn from the continuous range 0–15 semitones. Results show that the traditional consonances of the major third and the minor sixth become dissonances in the carillon and that small intervals (in particular 0.5–2.5 semitones) also become particularly dissonant. Computational modelling shows that these effects are primarily caused by interference between partials (e.g., beating), but that preference for harmonicity is also necessary to produce an accurate overall account of participants' preferences. The results support musicians' writings about the carillon and contribute to ongoing debates about the psychological mechanisms underpinning consonance perception, in particular disputing the recent claim that interference is largely irrelevant to consonance perception.

The perception of harmony has been the subject of many studies in the research literature, though little is known regarding how individuals vary in their ability to discriminate between different chord sequences. The aim of the current study was to construct an individual-differences test for the processing of harmonic information. A stimulus database of 5076 harmonic sequences was constructed and several harmonic features were computed from these stimulus items. Participants were tasked with selecting which chord differed between two similar four-chord sequences, and their response data were modeled with explanatory item response models using the computational harmonic features as predictors. The final model suggests that participants’ responses can be modeled using transitional probabilities between chords, voice-leading distance, and spectral pitch-class distance cues, with participant ability correlated to three subscales from Goldsmiths Musical Sophistication Index. The item response model was used to create an adaptive test of harmonic progression discrimination ability (HPT) and validated in a second study showing substantial correlations with other tests of musical perception ability, self-reported musical abilities, and a working memory task. The HPT is a new free and open-source tool for assessing individual differences in harmonic sequence discrimination. Initial data suggest this harmonic discrimination ability relies heavily on transitional probabilities within harmonic progressions.

A listening experiment was designed to test whether modern listeners perceive the same affective content in Baroque music as the composer intended to portray. Listeners rated three musical examples from Johann David Heinichen’s 1728 treatise Der General-Bass in der Composition for valence and arousal. Examples were chosen based on descriptions by the composer in which he outlined their intended affective content. Results showed a significant mismatch between original descriptions and listener ratings, indicating a change in the perceived affective content of the music. The historical variability of musical-emotional expression in general, with a focus on the role of structural emotion cues (particularly mode), is discussed, closing with suggestions for future research in the area of historical musical emotion

Recent research has confirmed that musical consonance is not only determined by the frequency ratios between tones, but also by the frequency spectra of the underlying tones (Marjieh et al., 2024). However, this prior research was limited to artificial tones, specifically tones built from a small number of pure tones, producing sounds that do not match the acoustic complexity of real musical instruments. Here we therefore investigate tones recorded from a real musical instrument, the Westerkerk Carillon, conducting a ‘dense rating’ experiment where participants (N = 113) rated musical intervals drawn from the continuous range 0-15 semitones. We show that the traditional consonances of the major third and the minor sixth become dissonances in the carillon, and we show that small intervals (in particular 0.5-2.5 semitones) also become particularly dissonant in the carillon. Through computational modelling we show that these effects are primarily caused by interference between partials (e.g. beating), but we also show that preference for harmonicity is also necessary to produce an accurate overall account of participants’ preferences. The results support musicians’ writings about the carillon and contribute to ongoing debates about the psychological mechanisms underpinning consonance perception.

Music is present in every known society but varies from place to place. What, if anything, is universal to music cognition? We measured a signature of mental representations of rhythm in 39 participant groups in 15 countries, spanning urban societies and Indigenous populations. Listeners reproduced random ‘seed’ rhythms; their reproductions were fed back as the stimulus (as in the game of ‘telephone’), such that their biases (the prior) could be estimated from the distribution of reproductions. Every tested group showed a sparse prior with peaks at integer-ratio rhythms. However, the importance of different integer ratios varied across groups, often reflecting local musical practices. Our results suggest a common feature of music cognition: discrete rhythm ‘categories’ at small-integer ratios. These discrete representations plausibly stabilize musical systems in the face of cultural transmission but interact with culture-specific traditions to yield the diversity that is evident when mental representations are probed across many cultures.

The phenomenon of musical consonance is an essential feature in diverse musical styles. The traditional belief, supported by centuries of Western music theory and psychological studies, is that consonance derives from simple (harmonic) frequency ratios between tones and is insensitive to timbre. Here we show through five large-scale behavioral studies, comprising 235,440 human judgments from US and South Korean populations, that harmonic consonance preferences can be reshaped by timbral manipulations, even as far as to induce preferences for inharmonic intervals. We show how such effects may suggest perceptual origins for diverse scale systems ranging from the gamelan’s slendro scale to the tuning of Western mean-tone and equal-tempered scales. Through computational modeling we show that these timbral manipulations dissociate competing psychoacoustic mechanisms underlying consonance, and we derive an updated computational model combining liking of harmonicity, disliking of fast beats (roughness), and liking of slow beats. Altogether, this work showcases how large-scale behavioral experiments can inform classical questions in auditory perception.

Recent advances in automatic music transcription have facilitated the creation of large databases of symbolic transcriptions of improvised music forms including jazz, where traditional notated scores are not normally available. In conjunction with music source separation models that enable audio to be “demixed” into separate signals for multiple instrument classes, these algorithms can also be applied to generate annotations for every musician in a performance. This can enable the analysis of interesting performer-level and ensemble-level features that have often been difficult to explore. To this end, we introduce JTD (Jazz Trio Database), a dataset of 44.5 hours of jazz piano solos accompanied by bass and drums, with automatically generated annotations for each performer. These annotations consist of onset, beat, and downbeat timestamps, alongside MIDI for the piano soloist. Suitable recordings, broadly representative of the “straight-ahead” jazz style, were identified by scraping user-based listening and discographic data; source separation models were applied to isolate audio for each performer in the trio; annotations were generated by applying appropriate algorithms to both the separated and mixed audio sources. Onset annotations generated by the pipeline achieved a mean F-measure of 0.94 when compared with ground truth annotations. We conduct several analyses of JTD, including with relation to swing and inter-performer synchronization. We anticipate that JTD will be useful in a variety of music information retrieval tasks, including artist identification and expressive performance modeling. We have made JTD, including the annotations and associated source code, available at https://github.com/HuwCheston/Jazz-Trio-Database.