Jeudi 4 Juin 2015

13h30-14h30  Salle B314 du Département Parole et Cognition (Bâtiment ENSE3, 11 rue des mathématiques, Saint Martin d?Hères)

Malinda Carpenter

School of Psychology and Neuroscience, university of St Andrews, St Andrews, Scotland

Abstract

In this talk I will present an overview of our work on infants? comprehension and production of pointing and iconic gestures, in support of a rich view of early communication.  For example, I will present studies that rule out lower-level explanations of early declarative and imperative pointing, and show that in both their comprehension and production of pointing infants take into account the experiences (common ground) they have shared with the particular person they are communicating with.  In addition, I will present both observational and experimental work showing that infants? pointing serves a wide variety of different functions beyond imperatives and declaratives (including reference to absent objects), and that infants produce creative iconic gestures perhaps earlier than previously thought.  Taken together, this work demonstrates the complexity, flexibility, and richness of infants? early communication, even preverbally.

Jeudi 11 Juin 2015

13h30-14h30  Salle B314 du Département Parole et Cognition (Bâtiment ENSE3, 11 rue des mathématiques, Saint Martin d?Hères)

Christian Herbst

Voice Research Lab, Department of Biophysics, Faculty of Science, Palacký university Olomouc, Czech Republic

Laboratory of Bioacustis, Department of Cognititive Biology, university Vienna

Elephant on the bench. Ex-vivo investigation of mammalian sound production

Excised larynx preparations allow studying the biophysics of mammalian sound production under controlled laboratory conditions. Research done in the past decades focused mainly on humans, but recently the approach has been extended to investigating nonhuman mammals. In this presentation, this author will present a partial overview of his own work with excised larynges, with relevance for the fields of bioacoustics and basic voice science. In particular, it will be shown that:

Elephants? voice production mechanism for infrasound vocalizations below 20 Hz conforms to the myo-elastic aerodynamic theory of voice production (MEAD). This physical principle thus extends across a remarkably large range of fundamental frequencies and body sizes in mammals, spanning more than four orders of magnitude. A method for visually and quantitatively assessing the regularity of vibrations of systems on the way to chaos is being presented. This method is applied to categorizing vibratory states of two excised red deer larynges on the bench, suggesting that irregular vibration increases glottal efficiency by about 3 dB, possibly giving the animals an energetic advantage during acoustic signalling.

The remainder of the talk is concerned with a critical evaluation of electroglottography (EGG), a low-cost non-invasive impedance measurement method for monitoring some oscillatory aspects of vocal fold vibration. The EGG waveform?s purported correspondence to the time-varying vocal fold contact area was investigated in an excised hemi-larynx experiment involving two high-speed video HSV cameras operating at 6000 fps, synchronized with EGG, and the results suggest a tolerable but not perfect agreement. Furthermore, an investigation of the coincidence of positive peaks in the derivative of the EGG waveform (dEGG) with incidents of glottal closure and opening, utilizing an excised larynx setup with synchronized ultra-HSV at 27000 fps was performed. Results show that dEGG peaks do not necessarily coincide with incidents of glottal closure and opening. Findings from these last two studies suggest that EGG should be interpreted and analyzed with care, and that further research is necessary to establish expected error margins.