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International audience; Timbre provides an important cue to identify musical instruments. Many timbral attributes covary with other parameters like pitch. This study explores listeners' ability to construct categories of instrumental sound sources from sounds that vary in pitch. Nonmusicians identified 11 instruments from the woodwind, brass, percussion, and plucked and bowed string families. In experiment 1, they were trained to identify instruments playing a pitch of C4, and in experiments 2 and 3, they were trained with a five-tone sequence (F#3–F#4), exposing them to the way timbre varies with pitch. Participants were required to reach a threshold of 75% correct identification in training. In the testing phase, successful listeners heard single tones (experiments 1 and 2) or three-tone sequences from (A3–D#4) (experiment 3) across each instrument's full pitch range to test their ability to generalize identification from the learned sound(s). Identification generalization over pitch varies a great deal across instruments. No significant differences were found between single-pitch and multi-pitch training or testing conditions. Identification rates can be predicted moderately well by spectrograms or modulation spectra. These results suggest that listeners use the most relevant acoustical invariance to identify musical instrument sounds, also using previous experience with the tested instruments.

Within certain categories of geometric shapes, prototypical exemplars that best characterize the category have been evidenced. These geometric prototypes are classically identified through the visual and haptic perception or motor production and are usually characterized by their spatial dimension. However, whether prototypes can be recalled through the auditory channel has not been formally investigated. Here we address this question by using auditory cues issued from timbre-modulated friction sounds evoking human drawing elliptic movements. Since non-spatial auditory cues were previously found useful for discriminating distinct geometric shapes such as circles or ellipses, it is hypothesized that sound dynamics alone can evoke shapes such as an exemplary ellipse. Four experiments were conducted and altogether revealed that a common elliptic prototype emerges from auditory, visual, and motor modalities. This finding supports the hypothesis of a common coding of geometric shapes according to biological rules with a prominent role of sensory-motor contingencies in the emergence of such prototypical geometry.

We show that sleep deprivation in otherwise normal and healthy adults can be detected through machine-learning analysis of vocal recordings. Importantly, we used fully generic acoustic features, derived from auditory models, together with our own machine learning interpretation method, derived from neuroscience. Sleep deprivation impacted two broad types of acoustic features: one related to speech rhythms, the other related to the timbre of the voice. Such features plausibly reflect two independent physiological processes: one explicit, the cognitive control of speech production, and the other implicit, the inflammation of the vocal apparatus. Crucially, the relative balance of the two processes varied widely across individuals, consistent with the known but unexplained variability in responses to sleep deprivation. Overall, our results suggest that the voice may be used as a “sleep stethoscope” to characterize the individual effects of sleep deprivation. Moreover, the method we applied is fully general and could be adapted to any future investigation of vocal biomarkers using machine-learning techniques.Author summarySleep deprivation has an ever-increasing impact on individuals and societies, from accidents to chronic conditions costing billions to health systems. Yet, to date, there is no quick and objective test for sleep deprivation. We show that sleep deprivation can be detected at the individual level with voice recordings, outlining future cost-effective and non-invasive “sleep stethoscopes”. Importantly, we focused on interpretability, which identified two independent physiological effects of sleep deprivation: a change in prosody, related to cognitive control, and a change in timbre, related to inflammation. This also revealed a striking variability in individual reactions to the same deprivation. The neuroscientific framework we developed, combining auditory models and machine learning, is freely available and could be adapted to any vocal biomarker.

International audience; Auditory roughness resulting from fast temporal beatings is often studied by summing two pure tones with close frequencies. Interestingly, the tactile counterpart of auditory roughness can be provided through touch with vibrotactile actua- tors. However, whether auditory roughness could also be perceived through touch and whether it exhibits similar characteris- tics are unclear. Here, auditory roughness perception and its tactile counterpart were evaluated using pairs of pure tone stimuli. Results revealed similar roughness curves in both modalities, suggesting similar sensory processing. This study attests to the relevance of such a paradigm for investigating auditory and tactile roughness in a multisensory fashion.

International audience; Humans excel at using sounds to make judgements about their immediate environment. In particular, timbre is an auditory attribute that conveys crucial information about the identity of a sound source, especially for music. While timbre has been primarily considered to occupy a multidimensional space, unravelling the acoustic correlates of timbre remains a challenge. Here we re-analyse 17 datasets from published studies between 1977 and 2016 and observe that original results are only partially replicable. We use a data-driven computational account to reveal the acoustic correlates of timbre. Human dissimilarity ratings are simulated with metrics learned on acoustic spectrotemporal modulation models inspired by cortical processing. We observe that timbre has both generic and experiment-specific acoustic correlates. These findings provide a broad overview of former studies on musical timbre and identify its relevant acoustic substrates according to biologically inspired models.

International audience; In this paper, a flexible control strategy for a synthesis model dedicated to nonlinear friction phenomena is proposed. This model enables to synthesize different types of sound sources, such as creaky doors, singing glasses, squeaking wet plates or bowed strings. Based on the perceptual stance that a sound is perceived as the result of an action on an object we propose a genuine source/filter synthesis approach that enables to elude physical constraints induced by the coupling between the interacting objects. This approach makes it possible to independently control and freely combine the action and the object. Different implementations and applications related to computer animation, gesture learning for rehabilitation and expert gestures are presented at the end of this paper.

International audience; The perception and production of biological movements is characterized by the 1/3 power law, a relation linking the curvature and the velocity of an intended action. In particular, motions are perceived and reproduced distorted when their kinematics deviate from this biological law. Whereas most studies dealing with this perceptual-motor relation focused on visual or kinaesthetic modalities in a unimodal context, in this paper we show that auditory dynamics strikingly biases visuomotor processes. Biologically consistent or inconsistent circular visual motions were used in combination with circular or elliptical auditory motions. Auditory motions were synthesized friction sounds mimicking those produced by the friction of the pen on a paper when someone is drawing. Sounds were presented diotically and the auditory motion velocity was evoked through the friction sound timbre variations without any spatial cues. Remarkably, when subjects were asked to reproduce circular visual motion while listening to sounds that evoked elliptical kinematics without seeing their hand, they drew elliptical shapes. Moreover, distortion induced by inconsistent elliptical kinematics in both visual and auditory modalities added up linearly. These results bring to light the substantial role of auditory dynamics in the visuo-motor coupling in a multisensory context.

International audience; Many studies stressed that the human movement execution but also the perception of motion are constrained by specific kinematics. For instance, it has been shown that the visuo-manual tracking of a spotlight was optimal when the spotlight motion complies with biological rules such as the so-called 1/3 power law, establishing the co-variation between the velocity and the trajectory curvature of the movement. The visual or kinesthetic perception of a geometry induced by motion has also been shown to be constrained by such biological rules. In the present study, we investigated whether the geometry induced by the visuo-motor coupling of biological movements was also constrained by the 1/3 power law under visual open loop control, i.e. without visual feedback of arm displacement. We showed that when someone was asked to synchronize a drawing movement with a visual spotlight following a circular shape, the geometry of the reproduced shape was fooled by visual kinematics that did not respect the 1/3 power law. In particular, elliptical shapes were reproduced when the circle is trailed with a kinematics corresponding to an ellipse. Moreover, the distortions observed here were larger than in the perceptual tasks stressing the role of motor attractors in such a visuo-motor coupling. Finally, by investigating the direct influence of visual kinematics on the motor reproduction, our result conciliates previous knowledge on sensorimotor coupling of biological motions with external stimuli and gives evidence to the amodal encoding of biological motion.

International audience; The present study investigated the effect of handwriting sonification on graphomotor learning. Thirty-two adults, distributed in two groups, learned four new characters with their non-dominant hand. The experimental design included a pre-test, a training session, and two post-tests, one just after the training sessions and another 24h later. Two characters were learned with and two without real-time auditory feedback (FB). The first group first learned the two non-sonified characters and then the two sonified characters whereas the reverse order was adopted for the second group. Results revealed that auditory FB improved the speed and fluency of handwriting movements but reduced, in the short-term only, the spatial accuracy of the trace. Transforming kinematic variables into sounds allows the writer to perceive his/her movement in addition to the written trace and this might facilitate handwriting learning. However, there were no differential effects of auditory FB, neither long-term nor short-term for the subjects who first learned the characters with auditory FB. We hypothesize that the positive effect on the handwriting kinematics was transferred to characters learned without FB. This transfer effect of the auditory FB is discussed in light of the Theory of Event Coding.

International audience; This study investigates the human ability to perceive biological movements through friction sounds produced by drawings and, furthermore, the ability to recover drawn shapes from the friction sounds generated. In a first experiment, friction sounds, real-time synthesized and modulated by the velocity profile of the drawing gesture, revealed that subjects associated a biological movement to those sounds whose timbre variations were generated by velocity profiles following the 1/3 power law. This finding demonstrates that sounds can adequately inform about human movements if their acoustic characteristics are in accordance with the kinematic rule governing actual movements. Further investigations of our ability to recognize drawn shapes were carried out in two association tasks in which both recorded and synthesized sounds had to be associated to both distinct and similar visual shapes. Results revealed that, for both synthesized and recorded sounds, subjects made correct associations for distinct shapes, while some confusion was observed for similar shapes. The comparisons made between recorded and synthesized sounds lead to conclude that the timbre variations induced by the velocity profile enabled the shape recognition. The results are discussed in the context of the ecological and ideomotor frameworks.

International audience; This paper presents an experiment dealing with the sensorimotor relation between auditory perception and graphical movements. Subjects were asked to synchronize their gestures with synthetic friction sounds. Some geometrical and dynamical parameters of the motor productions are analyzed according to the different mappings. This experiment provides a formal framework for a wider study which aims to evaluate the relation between audition, vision and gestures.

International audience; Even though we generally don't pay attention to the friction sounds produced when we are writing or drawing, these sounds are recordable, and can even evoke the underlying gesture. In this paper, auditory perception of such sounds, and the internal representations they evoke when we listen to them, is considered from the sensorimotor learning point of view. The use of synthesis processes of friction sounds makes it possible to investigate the perceptual influence of each gestures parameter separately. Here, the influence of the velocity profile on the mental representation of the gesture induced by a friction sound was investigated through 3 experiments. The results reveal the perceptual relevance of this parameter, and particularly a specific morphology corresponding to biological movements, the so-called 1/3-power law. The experiments are discussed according to the sensorimotor theory and the invariant taxonomy of the ecological approach.