Individual Differences Across the Lifespan
Explaining how and why individuals differ in their facility for language is crucial to understanding the background processes that support human language.
Taking a birds-eye view we can see that genetic differences between populations actually correlate with language differences. On an individual scale we notice that differences in language skills are observable from the first year of life, can predict later outcomes over the course of adulthood.
We will uncover individual differences across multiple components of language across the lifespan in both typical and atypical speakers, and incorporating cross-linguistic comparisons. This has important social outcomes: as language proficiency is a significant predictor of general psychological and social outcomes, identifying the source of individual and cross-linguistic differences allows us to better tackle the economic and social impact that language problems have on individuals and societies.
Using the latest experimental methodologies (e.g., eye-tracking) we will follow a representative sample of children longitudinally from infancy to age five, tracking how initial core cognitive and linguistic processing abilities support language development.
We will also take advantage of our region‘s unparalleled diversity to intensively study individual differences in adults, particularly prosodic structure. We will ask whether individual ability in processing prosodic structure varies in parallel across word, sentence and discourse prosody, whether the range of variation is equivalent across languages irrespective of prosodic system (stress, pitch accent etc.), whether it co-varies with other linguistic and non-linguistic performance measures, and in particular whether a correlation with musical ability exists, as claimed for processing of tonal structure.
Neural and neurocognitive bases of individual differences
Language is so complex that it is likely to be supported by several interacting neurocognitive mechanisms, including attention, memory and learning processes. A better categorisation of these mechanisms is essential to explain individual differences within typical populations and clinically significant differences attributable to language delay and impairment (either developmental or acquired). Studies under this theme will focus on both typical and atypical populations, as well as degenerative diseases (e.g., Alzheimer‘s, Parkinson‘s). Such populations — which are growing due to our aging population — offer an opportunity to investigate the neurobiological and neurocognitive underpinnings of language, and develop strategies to improve quality of life through understanding the language processing changes that occur and how language impairment is signalled and repaired. Language processing in the brain was long seen in terms of cortical function alone, yet a crucial role has been demonstrated for subcortical structures. Cross-disease comparisons will shed light on how language (sub)components are affected by primarily cortical (Alzheimer‘s) vs. subcortical (Parkinson‘s) damage. Related to this are the applied questions of how progressive language loss impacts social roles, activities and community participation, which we will explore.