The present proposal aims at investigating age-related processes (memorial or executive) that contribute to the often-observed decline in working memory capacity. The working memory model we adopt is Cowan's (2001) hierarchical, embedded-process model, which has a limited-capacity focus of attention at its core. Our own recent work has shown that age differences in accuracy of working memory performance is often tied to overflow of the immediate focus of attention: Older adults lose information at a higher rate than younger adults when the task forces them to switch between processing and storage, although they are not slower at retrieving the information that is still available. In a series of experiments (most purely behavioral in nature, some including the study of event-related potentials [ERP]) we investigate the source of this increased information-loss. We investigate the following questions: 1. Are the control processes that are implicated in focus switching -- that is, coordination (dual-tasking between encoding and retrieval), resistance to interference (as revealed by the filtering efficiency in the contralateral delay activity component in ERP), and updating (as revealed by late components in ERP), as well as the attention switch itself (again investigated using ERP) -- age-sensitive? 2. Are the mechanisms of binding and unbinding objects into working memory age-sensitive? (This question will be investigated using time-accuracy functions, as well as by analyzing access to independent features and bound objects.) 3. Does age diminish the propensity for flexible control (Braver et al., 2007), as measured by proactive control and/or behavioral plasticity? (This will be investigated by manipulating the need for precise control and investigating whether this manipulation changes the strategic approach to the task as revealed by patterns of RT and/or accuracy, as well as by studies of prolonged practice.) The study will aid in a deeper understanding of the origins of age deficits tied to memory and of subject- initiated remediation, potentially leading to diagnostic instruments and/or sensible interventions.
Older adults lose information at a faster rate than younger adults once the information leaves the immediate focus of attention. This proposal investigates whether this deficit is due to memory processes (retrieval, binding), executive control processes (coordination, updating, resistance to interference, attention switching), or both, and whether older adults are capable of flexible control over these processes. The study will aid in a deeper understanding of the origins of age deficits tied to memory and of subject-initiated remediation, potentially leading to diagnostic instruments and/or sensible interventions.
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