Visual Timing of Structured Dance Movements Resembles Auditory Rhythm Perception

Influences of temporal order in temporal reproduction

Despite the crucial role of complex temporal sequences, such as speech and music, in our everyday lives, our ability to acquire and reproduce these patterns is prone to various contextual biases. In this study, we examined how the temporal order of auditory sequences affects temporal reproduction. Participants were asked to reproduce accelerating, decelerating or random sequences, each consisting of four intervals, by tapping their fingers. Our results showed that the reproduction and the reproduction variability were influenced by the sequential structure and interval orders. The mean reproduced interval was assimilated by the first interval of the sequence, with the lowest mean for decelerating and the highest for accelerating sequences. Additionally, the central tendency bias was affected by the volatility and the last interval of the sequence, resulting in a stronger central tendency in the random and decelerating sequences than the accelerating sequence. Using Bayesian integration between the ensemble mean of the sequence and individual durations and considering the perceptual uncertainty associated with the sequential structure and position, we were able to accurately predict the behavioral results. The findings highlight the critical role of the temporal order of a sequence in temporal pattern reproduction, with the first interval exerting greater influence on mean reproduction and the volatility and the last interval contributing to the perceptual uncertainty of individual intervals and the central tendency bias.

Exposure to multisensory and visual static or moving stimuli enhances processing of nonoptimal visual rhythms

Research has shown that visual moving and multisensory stimuli can efficiently mediate rhythmic information. It is possible, therefore, that the previously reported auditory dominance in rhythm perception is due to the use of nonoptimal visual stimuli. Yet it remains unknown whether exposure to multisensory or visual-moving rhythms would benefit the processing of rhythms consisting of nonoptimal static visual stimuli. Using a perceptual learning paradigm, we tested whether the visual component of the multisensory training pair can affect processing of metric simple two integer-ratio nonoptimal visual rhythms. Participants were trained with static (AVstat), moving-inanimate (AVinan), or moving-animate (AVan) visual stimuli along with auditory tones and a regular beat. In the pre- and posttraining tasks, participants responded whether two static-visual rhythms differed or not. Results showed improved posttraining performance for all training groups irrespective of the type of visual stimulation. To assess whether this benefit was auditory driven, we introduced visual-only training with a moving or static stimulus and a regular beat (Vinan). Comparisons between Vinan and Vstat showed that, even in the absence of auditory information, training with visual-only moving or static stimuli resulted in an enhanced posttraining performance. Overall, our findings suggest that audiovisual and visual static or moving training can benefit processing of nonoptimal visual rhythms.

The effects of Parkinson's disease, music training, and dance training on beat perception and production abilities

Humans naturally perceive and move to a musical beat, entraining body movements to auditory rhythms through clapping, tapping, and dancing. Yet the accuracy of this seemingly effortless behavior varies widely across individuals. Beat perception and production abilities can be improved by experience, such as music and dance training, and impaired by progressive neurological changes, such as in Parkinson’s disease. In this study, we assessed the effects of music and dance experience on beat processing in young and older adults, as well as individuals with early-stage Parkinson’s disease. We used the Beat Alignment Test (BAT) to assess beat perception and production in a convenience sample of 458 participants (278 healthy young adults, 139 healthy older adults, and 41 people with early-stage Parkinson’s disease), with varying levels of music and dance training. In general, we found that participants with over three years of music training had more accurate beat perception than those with less training (p < .001). Interestingly, Parkinson’s disease patients with music training had beat production abilities comparable to healthy adults while Parkinson’s disease patients with minimal to no music training performed significantly worse. No effects were found in healthy adults for dance training, and too few Parkinson’s disease patients had dance training to reliably assess its effects. The finding that musically trained Parkinson’s disease patients performed similarly to healthy adults during a beat production task, while untrained patients did not, suggests music training may preserve certain rhythmic motor timing abilities in early-stage Parkinson’s disease.

Where and when to look: Sequential effects at the millisecond level

Learning and imitating a complex motor action requires to visually follow complex movements, but conscious perception seems too slow for such tasks. Recent findings suggest that visual perception has a higher temporal resolution at an unconscious than at a conscious level. Here we investigate whether high-temporal resolution in visual perception relies on prediction mechanisms and attention shifts based on recently experienced sequences of visual information. To that aim we explore sequential effects during four different simultaneity/asynchrony discrimination tasks. Two stimuli are displayed on each trial with varying stimulus onset asynchronies (SOA). Subjects decide whether the stimuli are simultaneous or asynchronous and give manual responses. The main finding is an advantage for different-order over same-order trials, when subjects decided that stimuli had been simultaneous on Trial t - 1 , and when Trial t is with an SOA slightly larger than Trial t - 1, or equivalent. The advantage for different-order trials disappears when the stimuli change eccentricity but not direction between trials (Experiment 2), and persists with stimuli displayed in the centre and unlikely to elicit a sense of direction (Experiment 4). It is still observed when asynchronies on Trial t - 1 are small and undetected (Experiment 3). The findings can be explained by an attention shift that is precisely planned in time and space and that incidentally allows subjects to detect an isolated stimulus on the screen, thus helping them to detect an asynchrony.

Speed Biases With Real-Life Video Clips

We live almost literally immersed in an artificial visual world, especially motion pictures. In this exploratory study, we asked whether the best speed for reproducing a video is its original, shooting speed. By using adjustment and double staircase methods, we examined speed biases in viewing real-life video clips in three experiments, and assessed their robustness by manipulating visual and auditory factors. With the tested stimuli (short clips of human motion, mixed human-physical motion, physical motion and ego-motion), speed underestimation was the rule rather than the exception, although it depended largely on clip content, ranging on average from 2% (ego-motion) to 32% (physical motion). Manipulating display size or adding arbitrary soundtracks did not modify these speed biases. Estimated speed was not correlated with estimated duration of these same video clips. These results indicate that the sense of speed for real-life video clips can be systematically biased, independently of the impression of elapsed time. Measuring subjective visual tempo may integrate traditional methods that assess time perception: speed biases may be exploited to develop a simple, objective test of reality flow, to be used for example in clinical and developmental contexts. From the perspective of video media, measuring speed biases may help to optimize video reproduction speed and validate "natural" video compression techniques based on sub-threshold temporal squeezing.

Your move or mine? Music training and kinematic compatibility modulate synchronization with self- versus other-generated dance movement

Motor simulation has been implicated in how musicians anticipate the rhythm of another musician's action to achieve interpersonal synchronization. Here, we investigated whether similar mechanisms govern a related form of rhythmic action: dance. We examined (1) whether synchronization with visual dance stimuli was influenced by movement agency, (2) whether music training modulated simulation efficiency, and (3) what cues were relevant for simulating the dance rhythm. Participants were first recorded dancing the basic Charleston steps paced by a metronome, and later in a synchronization task they tapped to the rhythm of their own point-light dance stimuli, stimuli of another physically matched participant or one matched in movement kinematics, and a quantitative average across individuals. Results indicated that, while there was no overall "self advantage" and synchronization was generally most stable with the least variable (averaged) stimuli, motor simulation was driven-indicated by high tap-beat variability correlations-by familiar movement kinematics rather than morphological features. Furthermore, music training facilitated simulation, such that musicians outperformed non-musicians when synchronizing with others' movements but not with their own movements. These findings support action simulation as underlying synchronization in dance, linking action observation and rhythm processing in a common motor framework.

Visual Enhancement of Illusory Phenomenal Accents in Non-Isochronous Auditory Rhythms

Musical rhythms encompass temporal patterns that often yield regular metrical accents (e.g., a beat). There have been mixed results regarding perception as a function of metrical saliency, namely, whether sensitivity to a deviant was greater in metrically stronger or weaker positions. Besides, effects of metrical position have not been examined in non-isochronous rhythms, or with respect to multisensory influences. This study was concerned with two main issues: (1) In non-isochronous auditory rhythms with clear metrical accents, how would sensitivity to a deviant be modulated by metrical positions? (2) Would the effects be enhanced by multisensory information? Participants listened to strongly metrical rhythms with or without watching a point-light figure dance to the rhythm in the same meter, and detected a slight loudness increment. Both conditions were presented with or without an auditory interference that served to impair auditory metrical perception. Sensitivity to a deviant was found greater in weak beat than in strong beat positions, consistent with the Predictive Coding hypothesis and the idea of metrically induced illusory phenomenal accents. The visual rhythm of dance hindered auditory detection, but more so when the latter was itself less impaired. This pattern suggested that the visual and auditory rhythms were perceptually integrated to reinforce metrical accentuation, yielding more illusory phenomenal accents and thus lower sensitivity to deviants, in a manner consistent with the principle of inverse effectiveness. Results were discussed in the predictive framework for multisensory rhythms involving observed movements and possible mediation of the motor system.

Sensorimotor Synchronization with Different Metrical Levels of Point-Light Dance Movements

Rhythm perception and synchronization have been extensively investigated in the auditory domain, as they underlie means of human communication such as music and speech. Although recent studies suggest comparable mechanisms for synchronizing with periodically moving visual objects, the extent to which it applies to ecologically relevant information, such as the rhythm of complex biological motion, remains unknown. The present study addressed this issue by linking rhythm of music and dance in the framework of action-perception coupling. As a previous study showed that observers perceived multiple metrical periodicities in dance movements that embodied this structure, the present study examined whether sensorimotor synchronization (SMS) to dance movements resembles what is known of auditory SMS. Participants watched a point-light figure performing two basic steps of Swing dance cyclically, in which the trunk bounced at every beat and the limbs moved at every second beat, forming two metrical periodicities. Participants tapped synchronously to the bounce of the trunk with or without the limbs moving in the stimuli (Experiment 1), or tapped synchronously to the leg movements with or without the trunk bouncing simultaneously (Experiment 2). Results showed that, while synchronization with the bounce (lower-level pulse) was not influenced by the presence or absence of limb movements (metrical accent), synchronization with the legs (beat) was improved by the presence of the bounce (metrical subdivision) across different movement types. The latter finding parallels the “subdivision benefit” often demonstrated in auditory tasks, suggesting common sensorimotor mechanisms for visual rhythms in dance and auditory rhythms in music.

Visual tuning and metrical perception of realistic point-light dance movements

Humans move to music spontaneously, and this sensorimotor coupling underlies musical rhythm perception. The present research proposed that, based on common action representation, different metrical levels as in auditory rhythms could emerge visually when observing structured dance movements. Participants watched a point-light figure performing basic steps of Swing dance cyclically in different tempi, whereby the trunk bounced vertically at every beat and the limbs moved laterally at every second beat, yielding two possible metrical periodicities. In Experiment 1, participants freely identified a tempo of the movement and tapped along. While some observers only tuned to the bounce and some only to the limbs, the majority tuned to one level or the other depending on the movement tempo, which was also associated with individuals' preferred tempo. In Experiment 2, participants reproduced the tempo of leg movements by four regular taps, and showed a slower perceived leg tempo with than without the trunk bouncing simultaneously in the stimuli. This mirrors previous findings of an auditory 'subdivision effect', suggesting the leg movements were perceived as beat while the bounce as subdivisions. Together these results support visual metrical perception of dance movements, which may employ similar action-based mechanisms to those underpinning auditory rhythm perception.