Linguistic focus in discourse processing in healthy older adults
A variety of aspects of language comprehension are known to be adversely affected by the normal processes of adult ageing. Thus, comprehension in the elderly is reduced by increases in sentential complexity (e.g., Kemper, 1997), and the capacity to suppress irrelevant meanings from working memory is reduced (May et al., 1999). In the present studies, we investigated any potential loss in utilising structural cues to processing such as main-subordinate clause structure and focus. There has been no earlier work on whether focus cues work effectively in the elderly. If focus cues are as effective in the elderly as in the young, then there is the possibility that focus could serve to offset difficulties of processing complex sentences. Furthermore, in processing sentences with focussed and non-focussed components, it is possible that due to resource limitations, the elderly will show (relatively) enhanced processing focussed components, to the detriment of processing backgrounded information. Little is known about how focus effects and depth of processing may be modulated by adult aging. Cleft sentences manipulate focus, thereby influencing the question a sentence answers (Sanford & Sturt, 2002). In three self-paced reading time experiments, we investigated whether the effects of focus observed in the young hold in the elderly, or whether they are reduced or enhanced. Experiment 1 investigated how structural information influences the accessibility of referents from main and subordinate clauses. Cooreman & Sanford (1996) showed that for younger adults individuals mentioned in the main clause of complex sentences were more accessible than those mentioned in subordinate clauses, regardless of order. Experiment 2 explored how proper names and recency of mention influences reading time. It is known that younger adults are more likely to respond faster to a proper-named character than one described by a role (Sanford et al., 1988). Experiment 3 examined the influence of focus through it-clefts, pseudo wh-clefts compared to a neutral baseline. The results will be discussed in terms of cognitive capacity and whether there is evidence of any deterioration or enhancement of focus effects in older adults.