Mapping the effects of stimulus history on perception

There is an ongoing debate on the effects of stimulus history on perception. Recent studies have shown that repeated perceptual decisions to similar stimuli lead to contextual effects, correlated both negatively with the past (negative aftereffects) and positively (serial dependence), sometimes at the same time (Chopin and Mamassian, Current Biology, 2012; Fritsche et al., Current Biology, 2017). However, less attention has been given to understanding how these effects evolve for stimuli further in the past.

Computing perceived gaze direction

I will be presenting some experiments from my PhD thesis, in which I examined how the perception of another’s gaze direction is computed by the human observer, and in turn, how we can compute the direction of gaze that is perceived by the observer. The perception of gaze direction involves the integration of a large variety of visual cues, such as the spatial offset of the pupil, the contrast polarity within the eye region, the orientation of the head, and more indirectly, the emotional expression of the face, and the surrounding context the face is presented within.

Perception of multiple pitches: Sequential and simultaneous pitch relationships

The perception of pitch, a dimension of sound that is important for music perception, speech perception, and sound source segregation, is influenced by its context, both sequential and simultaneous. In music, pitch sequences form melodic contours, and simultaneous pitches form chords and harmony. A series of experiments investigated the perception of melodic contour in pitch as well as two other auditory dimensions, brightness and loudness.

Modulations temporelles

Les sons complexes, y compris la parole, peuvent être représentés comme une somme de sinusoïdes modulées en amplitude et en fréquence (AM et FM). Pour la plupart des sons de communication, les cadences d’AM et de FM varient généralement entre 1 et environ 100-500 Hz (les cadences les plus saillantes étant comprises entre environ 1 et 20 Hz). Chaque sinusoïde AM-FM engendre un patron complexe d '«excitation sensorielle» à la sortie des filtres cochléaires.

Psychophysique

La méthode utilisée au sein de notre laboratoire et notre département de sciences cognitives de l'Ecole normale supérieure est une méthode scientifique. Il s'agit de la méthode hypothético-déductive utilisée en sciences expérimentales (sciences du vivant, physique, chimie, géosciences, etc.).

Crossmodal interactions without visual awareness

Binocular rivalry is a form of perceptual bistability in which each monocular image is temporarily removed from visual awareness in favour of the other. I will  present psychophysical evidence investigating crossmodal interactions between touch, audition and vision during binocular rivalry. We show that haptic signals interfere with the dynamics of binocular rivalry outside of visual awareness, that is, by rescuing the congruent visual stimulus from binocular rivalry suppression.

A brief introduction to deep learning and its application to multichannel speech enhancement

Over the past decade deep learning has become the state-of-the-art in many applications including several tasks of speech and audio processing. It has recently been applied to multichannel speech enhancement, outperforming most of the classical approaches. In this presentation, I will present a brief history of neural and a short overview of some deep learning architectures that are currently used. I will then describe the problem of multichannel speech enhancement and a solution to this problem: the multichannel Wiener filters.