Foundations of speech perception and language comprehension
Screaming is an ability we share with many other primates, and which we possess long before we learn to express our affective state with speech. Previous studies focusing on fearful screams highlighted certain acoustic features, such as roughness, unexploited by speech (Arnal et al., 2015), leading to activation of the amygdala and other subcortical structures critical for danger appraisal. However, screams are not exclusively fearful. But how diverse are the acoustic properties of screams compared to the various affective states expressed?
The tone of the voice carries information about the emotional state or intention of a speaker. Whereas the nature of acoustic features of contrasted prosodic signals has attracted a lot of attention in the last decades (particularly since Banse & Scherer, 1996), the communication of emotions/intentions remains poorly understood. Also, most of listeners seem to share the ‘code’ (or interpret adequately a prosodic signal) to access emotions/intentions of speakers but misunderstandings easily occur. This project focuses on the cognitive processes involved in prosody comprehension.
Bilingualism has become common. Infants' auditory cortex undergoes structural maturation during the first three years (Yakovlev & Lecours, 1967). They develop an auditory capacity to specifically recognize acoustic patterns used in their native language (e.g., Kuhl et al. 1992). Bilinguals, compared to monolinguals, are exposed to and learn to identify greater number of speech sounds. We hypothesize that distinguishing between and storing larger inventories leads to the expansion of auditory cortical areas and the establishment of denser connections within subregions.
Humans naturally tune in to the rhythm of speech (Giraud & Poeppel, 2012). Recent work has shown that low-frequency brain rhythms have been shown concurrently to track the main constituents in a linguistic hierarchy: phrases and sentences (Ding et al., 2016). Notably, brain rhythms were cross-linguistically tested using isochronous speech in English and Mandarin Chinese. Given the variable nature of linguistic constituents, it is however unclear whether the implicit knowledge of linguistic structure contributes in tracking linguistic constituents (phrases, sentences) of variable duration.