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.

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.

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.

Sensorineural hearing loss caused by cochlear damage impacts differentially the auditory processing of temporal-envelope and temporal fine-structure information. Our work suggests that cochlear damage preserves and even enhances the auditory detection of temporal-envelope cues whereas it degrades the detection of temporal fine-structure cues. The enhancement of temporal-envelope cues is consequent to the loss of the active mechanism in the cochlea and maybe abnormal short-term neural adaptation in the auditory nerve.

Complex sounds including speech can be represented as a sum of amplitude- and frequency- modulated (AM and FM) sinusoids. For most communication sounds, AM and FM rates typically range between 1 and about 100-500 Hz (the most salient rates ranging between about 1 and 20 Hz). Each AM-FM sinusoid elicits a complex pattern of “sensory excitation” at the output of cochlear filters.

The method used in our laboratory is a scientific method. This is the hypothetico-deductive method used in experimental sciences (life sciences, physics, chemistry, earth sciences, etc.).

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.

Abstract - Part 1