VIAWORD · From speech and print to meaning: an integrated account of word recognition in young and older adults.

From speech and print to meaning: an integrated account of word recognition in young and older adults.

Language is a uniquely human skill that has allowed us to advance our knowledge and culture over millions of years. Humans can access word meaning via written or spoken language. Thus, comparing the neural basis of the written and spoken word recognition system can improve our theoretical understanding of such a fundamental human cognitive process. In addition, language is a skill that we use throughout our lives. Therefore, understanding the aspects of language that are preserved or decline as we age can help us to maintain such an essential cognitive process. The main goals of the projects were: 1) to identify modality-specific (visual vs. auditory) neurocognitive processes of word recognition using electrophysiology, and 2) to identify age-related changes in word recognition neurocognitive processes by comparing young and older adults. To achieve goal one, we compared the results of a speeded and a delayed lexical decision task (in an LDT participants are asked to discriminate words from pseudowords) presented to young adults in the written, spoken and audiovisual (written+spoken) modality while electroencephalogram was recorded. In a LDT, participants are asked to discriminate words from pseudowords. To achieve goal two we compared the brain activity of young and older adults while they performed a delayed LDT. The main results from goal one show that word meaning –as indexed by an electrophysiologic lexicality effect—was accessed earlier in the visual than in the spoken modality, suggesting the rapid availability of written stimuli leads lexical access. In addition, access to word meaning was modulated by the time pressure participants were asked to make a response: the lexicality lasted longer in the speeded than in the delayed LDT. Further, the lexicality effect was observed again at the time participants made a response in the delayed LDT, suggesting re-accessing of the word in semantic memory in order to accurately perform the task. The results from goal two show that there are brain dynamics’ differences between young and older adults when they recognize words. The main findings include a right-lateralized distribution of the lexicality effect in older adults, suggesting a specialized semantic system in the aging brain, and longer activation of the effect in the visual and audiovisual modalities in older relative to young adults, suggesting that older adults maintain the concept active in memory until the time of responding in order to perform as accurately as young adults.

Data: CORDIS, © European Union