Visual cues in musical synchronisation

Although music performance is generally thought of as an auditory activity in the Western tradition, the presence of continuous visual information in live music contributes to the cohesiveness of music ensembles, which presents an interesting psychological phenomenon in which audio and visual cues are presumably integrated. In order to investigate how auditory and visual sensory information are combined in the basic process of synchronising movements with music, this thesis focuses on both musicians and nonmusicians as they respond to two sources of visual information common to ensembles: the conductor, and the ancillary movements (movements that do not directly create sound; e.g. body sway or head nods) of co-performers. These visual cues were hypothesized to improve the timing of intentional synchronous action (matching a musical pulse), as well as increasing the synchrony of emergent ancillary movements between participant and stimulus. The visual cues were tested in controlled renderings of ensemble music arrangements, and were derived from real, biological motion. All three experiments employed the same basic synchronisation task: participants drummed along to the pulse of tempo-changing music while observing various visual cues. For each experiment, participants’ drum timing and upper-body movements were recorded as they completed the synchronisation task. The analyses used to quantify drum timing and ancillary movements came from theoretical approaches to movement timing and entrainment: information processing and dynamical systems. Overall, this thesis shows that basic musical timing is a common ability that is facilitated by visual cues in certain contexts, and that emergent ancillary movements and intentional synchronous movements in combination may best explain musical timing and synchronisation

Cognitive Factors Predicting Expressive Music Synchronization: Roles for Auditory Imagery and Working Memory

Sensorimotor synchronization (SMS) is especially apparent¿and therefore readily studied¿in musical settings, as most people are naturally able to perceive a musical beat and synchronize to it (e.g. by tapping a finger). SMS processes have been tested extensively using pseudo-musical pacing signals, so we chose to extend this by using naturalistic, expressively timed piano music, characterized by slight tempo fluctuations for artistic interpretation. Previous research has also shown that people vary greatly in their SMS abilities. Given the dynamic nature and variability of SMS, we hypothesized that individual differences in working memory and auditory imagery¿both fluid, cognitive processes¿would predict SMS at two levels: 1) asynchrony (a measure of synchronization error), and 2) anticipatory timing (i.e. predicting, rather than reacting to beat onsets). In Experiment 1a, participants (N = 36) completed two working memory tests, a tempo imagery test, a pitch imagery test, and a self-report test of auditory imagery with separate subscales for vividness (clarity of an image) and control (ability to alter an image). They were then tested in a SMS-tapping task. In Experiment 1b, the same set of tasks was given to highly trained musicians. In Experiment 2, participants were given an expressive timing perception test to see the extent to which the cognitive variables related to perception without action. Hierarchical regression models were used to assess the contribution of the cognitive variables to SMS. Results showed dissociations among imagery types as they relate to asynchrony, perception, and suggest a role for working memory in anticipatory timing. Musicians performed better on the SMS task, but showed fewer correlations between the cognitive variables and SMS. These results suggest that in nonmusicians imagery for pitches and temporal patterns is important for synchronizing to an auditory stimulus, but working memory is implicated in strategically synchronizing via anticipation of beat onsets

Working Memory and Auditory Imagery Predict Sensorimotor Synchronisation With Expressively Timed Music

Sensorimotor synchronisation (SMS) is prevalent and readily studied in musical settings, as most people are able to perceive and synchronise with a beat (e.g., by finger tapping). We took an individual differences approach to understanding SMS to real music characterised by expressive timing (i.e., fluctuating beat regularity). Given the dynamic nature of SMS, we hypothesised that individual differences in working memory and auditory imagery—both fluid cognitive processes—would predict SMS at two levels: (1) mean absolute asynchrony (a measure of synchronisation error) and (2) anticipatory timing (i.e., predicting, rather than reacting to beat intervals). In Experiment 1, participants completed two working memory tasks, four auditory imagery tasks, and an SMS-tapping task. Hierarchical regression models were used to predict SMS performance, with results showing dissociations among imagery types in relation to mean absolute asynchrony, and evidence of a role for working memory in anticipatory timing. In Experiment 2, a new sample of participants completed an expressive timing perception task to examine the role of imagery in perception without action. Results suggest that imagery vividness is important for perceiving and control is important for synchronising with irregular but ecologically valid musical time series. Working memory is implicated in synchronising by anticipating events in the series

Incoherently pumped continuous wave optical parametric oscillator broadened by non-collinear phasematching

In this paper, we report on a singly resonant optical parametric oscillator (OPO) pumped by an amplified spontaneous emission (ASE) source. The pump focusing conditions allow non-collinear phasematching, which resulted in a 230 nm (190 cm$^{-1}$) spectral bandwidth. Calculations indicate that such phasematching schemes may be used to further broaden OPO spectral bandwidths.Comment: 7 pages 4 figure

Does movement amplitude of a co-performer affect individual performance in musical synchronization?

Interpersonal coordination in musical ensembles often involves multisensory cues, with visual information about body movements supplementing co-performers’ sounds. Previous research on the influence of movement amplitude of a visual stimulus on basic sensorimotor synchronization has shown mixed results. Uninstructed visuomotor synchronization seems to be influenced by amplitude of a visual stimulus, but instructed visuomotor synchronization is not. While music performance presents a special case of visually mediated coordination, involving both uninstructed (spontaneously coordinating ancillary body movements with co-performers) and instructed (producing sound on a beat) forms of synchronization, the underlying mechanisms might also support rhythmic interpersonal coordination in the general population. We asked whether visual cue amplitude would affect nonmusicians’ synchronization of sound and head movements in a musical drumming task designed to be accessible regardless of musical experience. Given the mixed prior results, we considered two competing hypotheses. H1: higher amplitude visual cues will improve synchronization. H2: different amplitude visual cues will have no effect on synchronization. Participants observed a human-derived motion capture avatar with three levels of movement amplitude, or a still image of the avatar, while drumming along to the beat of tempo-changing music. The moving avatars were always timed to match the music. We measured temporal asynchrony (drumming relative to the music), predictive timing, ancillary movement fluctuation, and cross-spectral coherence of ancillary movements between the participant and avatar. The competing hypotheses were tested using conditional equivalence testing. This method involves using a statistical equivalence test in the event that standard hypothesis tests show no differences. Our results showed no statistical differences across visual cues types. Therefore, we conclude that there is not a strong effect of visual stimulus amplitude on instructed synchronization

The Living Room of the Future

Emergent media services are turning towards the use of audience data to deliver more personalised and immersive experiences. We present the Living Room of the Future (LRoTF), an embodied design fiction built to both showcase future adaptive physically immersive media experiences exploiting the Internet of Things (IoT) and to probe the adoption challenges confronting their uptake in everyday life. Our results show that audiences have a predominantly positive response to the LRoTF but nevertheless entertain significant reservations about adopting adaptive physically immersive media experiences that exploit their personal data. We examine ‘user’ reasoning to elaborate a spectrum of adoption challenges that confront the uptake of adaptive physically immersive media experiences in everyday life. These challenges include data legibility, privacy concerns and potential dystopias, concerns over agency and control, the social need for customisation, value trade-off and lack of trust

Effects of fine sediment on seagrass meadows: A case study of Zostera muelleri in pāuatahanui inlet, New Zealand

Seagrass meadows are vulnerable to fine sediment (mud) pollution, with impacts usually attributed to reduction in submerged light. Here we tested two non-exclusive hypotheses, that mud particles (≤63 μm) impact seagrasses through both (1) the light climate and (2) changes in substrate physico-chemistry. We tested these hypotheses in Pāuatahanui Inlet, New Zealand, by comparing seagrass presence, abundance, and health, together with light climate and substrate physico-chemistry at contrasting habitats where (1) seagrass used to thrive but no longer grows (historical seagrass), (2) seagrass still persists (existing seagrass) and (3) seagrass has been present recently, but not currently (potential seagrass). Historical seagrass substrate had significantly higher mud (35% average), bulk density (1.5 g cm⁻³), porewater ammonium concentration (65 μM), and a more reduced redox profile (negative redox at only 2 cm soil depth) as well as a lower light availability when submerged compared to other habitats, while total daily light exposure differed little between habitats. This suggests that failure of seagrass to recolonize historical seagrass habitat reflects substrate muddiness and consequent unfavorable rhizosphere conditions. Our results provide evidence for the multi-stressor effects of fine sediment on seagrasses, with substrate suitability for seagrass being detrimentally affected even where light exposure seems sufficient

Street Connectivity is Negatively Associated with Physical Activity in Canadian Youth

Street connectivity, defined as how well streets connect to one and other and the density of intersections, is positively associated with active transportation in adults. Our objective was to study the relation between street connectivity and physical activity in youth. Study participants consisted of 8,535 students in grades 6–10 from 180 schools across Canada who completed the 2006 Health Behaviour in School-aged Children (HBSC) survey. Street connectivity was measured in a 5 km circular buffer around these schools using established geographic information system measures. Physical activity performed outside of school hours was assessed by questionnaire, and multi-level regression analyses were used to estimate associations with street connectivity after controlling for several covariates. Compared to students living in the highest street connectivity quartile, those in the second (relative risk = 1.22, 95% confidence interval = 1.10–1.35), third (1.25, 1.13–1.37), and fourth (1.21, 1.09–1.34) quartiles were more likely to be physically active outside of school. In conclusion, youth in neighbourhoods with the most highly connected streets reported less physical activity outside of school than youth from neighbourhoods with less connected streets. Relationships between street connectivity and physical activity reported in this national study are in the opposite direction to those previously observed for active transportation in adult populations