Our cultural adages tell us that with age and experience comes wisdom, and, indeed, empirical data show that healthy older adults often have richer vocabularies and augmented stores of world knowledge (Light, 1992). However, aging also brings decline in both physical and psychological abilities: a sore back or more difficult climb up the stairs may be accompanied by decreased ability to remember a phone number or the grocery list, increased tip-of-the-tongue experiences, and a harder time focusing concentration on a particular task. These psychological facets of normal aging are likely to become more consequential as life expectancy continues to increase in the developed world and as medicine offers more solutions to the physical problems of aging. It is clear that research on cognitive aging is an imperative so that intellectual functioning can be correspondingly prolonged.#R##N##R##N#Language comprehension is a particularly critical skill for normal everyday life, and one that occupies a fairly unique position in cognitive aging research. As opposed to memory, executive function, and most other cognitive phenomena, important aspects of comprehension have been thought to be relatively protected against age-related degradation. Although certain language tasks become harder with age, especially when resources are heavily taxed, older adults report little change in their ability to engage in conversations, read novels or the newspaper, and use language in everyday situations (Light & Burke, 1993). Behavioral evidence corroborates these subjective impressions, in that older adults and younger adults often show generally similar performance on comprehension-related tasks (Burke & Shafto, 2008). Yet this stability is surprising in light of the myriad age-related cognitive and neural changes that have been documented, many of which are required for the rapid, complex processes involved in language (Craik & Salthouse, 2008). It seems likely, therefore, that across the lifespan comprehension goals may be successfully met via importantly different configurations of cognitive and neural resources.#R##N##R##N#In fact, recent evidence -- particularly from measures of processing during on-line comprehension, such as electrophysiological brain activity collected as participants read or listen to language -- reveals that aging is associated with both quantitative and qualitative changes in the processes used to comprehend language. Work using event-related brain potentials (ERPs), which provide functionally and temporally specific indices of cognitive processing, has shown that the organization of knowledge in what is generally referred to as “semantic memory” does seem to be similar for younger and older adults and that basic aspects of word processing remain stable across the life-span. However, there are important age-related – and individual – differences in how that word-related information is then used during on-line language processing. Delineating these processing differences is critical for building an understanding of how the aging brain makes the best use of available resources, skills, and knowledge to afford rapid and successful comprehension, thereby allowing older adults to gain information from the environment and communicate in order to build and maintain social ties. Our review focuses on ERP findings at the word, sentence, and discourse levels, and in late controlled processes involved in the online construction of message-level meaning from text or speech unfolding in real time. We conclude with a discussion of individual differences that modulate the changes that are seen at the group level.
['Edward W. Wlotko', 'Chia Lin Lee', 'Kara D. Federmeier']
Language of the Aging Brain: Event-Related Potential Studies of Comprehension in Older Adults