Paolo Ammirante

Vibrotactile discrimination of musical timbre.

Five experiments investigated the ability to discriminate between musical timbres based on vibrotactile stimulation alone. Participants made same/different judgments on pairs of complex waveforms presented sequentially to the back through voice coils embedded in a conforming chair. Discrimination between cello, piano, and trombone tones matched for F0, duration, and magnitude was above chance with white noise masking the sound output of the voice coils (Experiment 1), with additional masking to control for bone-conducted sound (Experiment 2), and among a group of deaf individuals (Experiment 4a). Hearing (Experiment 3) and deaf individuals (Experiment 4b) also successfully discriminated between dull and bright timbres varying only with regard to spectral centroid. We propose that, as with auditory discrimination of musical timbre, vibrotactile discrimination may involve the cortical integration of filtered output from frequency-tuned mechanoreceptors functioning as critical bands.

Timing skills and expertise: discrete and continuous timed movements among musicians and athletes

Introduction: Movement-based expertise relies on precise timing of movements and the capacity to predict the timing of events. Music performance involves discrete rhythmic actions that adhere to regular cycles of timed events, whereas many sports involve continuous movements that are not timed in a cyclical manner. It has been proposed that the precision of discrete movements relies on event timing (clock mechanism), whereas continuous movements are controlled by emergent timing. We examined whether movement-based expertise influences the timing mode adopted to maintain precise rhythmic actions. Materials and Method: Timing precision was evaluated in musicians, athletes and control participants. Discrete and continuous movements were assessed using finger-tapping and circle-drawing tasks, respectively, based on the synchronization-continuation paradigm. In Experiment 1, no auditory feedback was provided in the continuation phase of the trials, whereas in Experiment 2 every action triggered a feedback tone. Results: Analysis of precision in the continuation phase indicated that athletes performed significantly better than musicians and controls in the circle-drawing task, whereas musicians were more precise than controls in the finger tapping task. Interestingly, musicians were also more precise than controls in the circle-drawing task. Results also showed that the timing mode adopted was dependent on expertise and the presence of auditory feedback. Discussion: Results showed that movement-based expertise is associated with enhanced timing, but these effects depend on the nature of the training. Expertise was found to influence the timing strategy adopted to maintain precise rhythmic movements, suggesting that event and emergent timing mechanisms are not strictly tied to specific tasks, but can both be adopted to achieve precise timing.

Continuation tapping to triggered melodies: motor resonance effects of melodic motion.

Common Coding theory predicts that perceived action should resonate in produced action to which it bears some resemblance. Here we show that the qualities of motion commonly attributed to melodies are instantiated in motor plans that control timed movements. Participants attempted to tap a steady beat. Each tap triggered a sounded tone, and successive tones were systematically varied in pitch to form short melodies. Tapping behavior was monitored with motion capture. Although instructed to ignore them, triggered tones systematically affected timing and finger movement. When slower melodic motion was implied by a contour change or a smaller pitch displacement, the interval-tap interval (ITI) was longer. When faster melodic motion was implied by a preserved pitch contour or a larger pitch displacement, ITI was shorter. Kinematic recordings suggested that ITI Error arose from an initial failure to disambiguate perception (i.e., velocity implied by melodic motion) from action (i.e., finger velocity [FV]). Early in the tap trajectory, slower FV was associated with longer ITI and faster FV was associated with shorter ITI. These associations were reversed near mid-trajectory, suggesting a transition from execution of motor planning to online control (Glover et al. in Exp Brain Res 154:103–108, 2004).

Ideomotor effects of pitch on continuation tapping

The ideomotor principle predicts that perception will modulate action where overlap exists between perceptual and motor representations of action. This effect is demonstrated with auditory stimuli. Previous perceptual evidence suggests that pitch contour and pitch distance in tone sequences may elicit tonal motion effects consistent with listeners’ implicit awareness of the lawful dynamics of locomotive bodies. To examine modulating effects of perception on action, participants in a continuation tapping task produced a steady tempo. Auditory tones were triggered by each tap. Pitch contour randomly and persistently varied within trials. Pitch distance between successive tones varied between trials. Although participants were instructed to ignore them, tones systematically affected finger dynamics and timing. Where pitch contour implied positive acceleration, the following tap and the intertap interval (ITI) that it completed were faster. Where pitch contour implied negative acceleration, the following tap and the ITI that it completed were slower. Tempo was faster with greater pitch distance. Musical training did not predict the magnitude of these effects. There were no generalized effects on timing variability. Pitch contour findings demonstrate how tonal motion may elicit the spontaneous production of accents found in expressive music performance.

Melodic Accent as an Emergent Property of Tonal Motion

In a previous continuation tapping study (Ammirante, Thompson, & Russo, in press), each tap triggered a discrete tone in a sequence randomly varying in pitch height and contour. Although participants were instructed to ignore the tones, pitch distance and pitch contour influenced intertap interval (ITI) and tap velocity (TV). The current study replicated these findings with original melodies. Results were interpreted as an effect of apparent tonal motion, with deviation in ITI and TV mirroring implied tonal acceleration. Due to overlapping perceptual and motor representations, participants may have failed to disambiguate acceleration implied by tonal motion from the acceleration of their finger trajectory. Dissociative effects of pitch distance on ITI and pitch contour on TV implied that pitch distance influences the initial finger extension while pitch contour influences later finger flexion. Acceleration in ITI and TV were also both correlated with melodic accent strength values from perceptual data (Thomassen, 1982), suggesting that perception and production of melodic accent emerge from shared action associations.