Site en français
LEYBAERT Jacqueline


Laboratory of Cognition, Language, and Development

The research focus of the LCLD concerns the study of human cognition and language with a developmental and educational perspective, a field also known as developmental or educational neuroscience. Although a large part of the research is based on behavioral experimental techniques, with normally developing children, children with cognitive or sensory developmental impairments and adult participants, current projects also integrate computational modelling as well as neuroimaging techniques (ERP, fMRI, MEG).
The lab has a long tradition of research on visual word recognition processes, and on reading and spelling acquisition in typical and atypical development. Major themes of active investigation at the moment concern aspects of language processing and reading — language processing across modalities; spoken and printed word recognition processes; written language acquisition disorders (dyslexias/dysgraphias); language development in hearing-impaired persons; bilingualism and second language acquisition.
But also, more recently, we have started research on numerical and mathematical cognition: current projects include the analysis of the relationships between early preverbal numerical abilities and later skills; influence of conventional notation systems on quantity perception and estimation; numerical and arithmetic developmental disorders and their link with language ability.
LCLD is a member of CRCN ( and UNI (


Development of audio-visual integral of sensory information in speech perception

The project aims at examining the role of visual information (lip reading) in speech perception under normal and noisy conditions. Adults, children at different ages, as well as cases of atypical language development will be considered, such as deaf children with cochlear implants, or dysphasic children. A combination of behavioral and neuroimaging techniques is used. A second project aims deals with the integration of signals ensuing from lips and hands in cued speech perception. Electrophysiological methods and eye tracking are used to investigate these issues.

The impact of numerical symbolic knowledge on the number sense

Our goal is to investigate interactions between preverbal numerical abilities and more elaborate numerical capacities, as well as the causality of these relationships during the development. More specifically, we are studying the potential impact of the acquisition of numerical symbols (counting words and Arabic numbers) on the number sense indexed by the sensitivity in numerosity discrimination. By comparing performance of controls and performance of participants who presented a retardation in the access to the numerical symbols (blind or deaf people), we will be able to assess the extent to which the knowledge about symbolic number is crucial in the refinement of preverbal numerical abilities. 

The elaboration of an instrument to evaluate the lexical level of sign language in children presenting profound deafness.

The Sign Language was introduced these last years into the special education for deaf children. The purpose of the project is to elaborate a tool allowing to estimate the level of the children exposed to the Sign Language in various contexts.

Numerical cognition in children with early language impairments

This project aims at examining the numerical and arithmetical development of children with early language deficits.