Context processing in older adults: evidence for a theory relating cognitive control to neurobiology in healthy aging

A theory of cognitive aging is presented in which healthy older adults are hypothesized to suffer from disturbances in the processing of context that impair cognitive control function across multiple domains, including attention, inhibition, and working memory. These cognitive disturbances are postulated to be directly related to age-related decline in the function of the dopamine (DA) system in the prefrontal cortex (PFC). A connectionist computational model is described that implements specific mechanisms for the role of DA and PFC in context processing. The behavioral predictions of the model were tested in a large sample of older (N = 81) and young (N = 175) adults performing variants of a simple cognitive control task that placed differential demands on context processing. Older adults exhibited both perfor-mance decrements and, counterintuitively, performance improvements that are in close agreement with model predictions. There are a number of cognitive and biological changes that appear to occur during healthy aging. At the cognitive level, these changes include declines in functions such as episodic and work-ing memory, attention, and inhibition (e.g., Hasher & Zacks, 1988; Moscovitch & Winocur, 1995; Salthouse, 1990; Spieler, Balota, &amp