One of the classic questions about human thinking concerns the limited ability to perform two cognitive tasks concurrently, such as a novice driver's difficulty in simultaneously driving and conversing. Limitations on the concurrent performance of two unrelated tasks challenge the tacitly assumed independence of two brain systems that seemingly have little overlap. The current study used fMRI (functional magnetic resonance imaging) to measure cortical activation during the concurrent performance of two high-level cognitive tasks that involve different sensory modalities and activate largely nonoverlapping areas of sensory and association cortex. One task was auditory sentence comprehension, and the other was the mental rotation of visually depicted 3-D objects. If the neural systems underlying the two tasks functioned independently, then in the dual task the brain activation in the main areas supporting the cognitive processing should be approximately the conjunction of the activation for each of the two tasks performed alone. We found instead that in the dual task, the activation in association areas (primarily temporal and parietal areas of cortex) was substantially less than the sum of the activation when the two tasks were performed alone, suggesting some mutual constraint among association areas. A similar result was obtained for sensory areas as well.

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Previous research has demonstrated that older adults' memory performance is adversely affected by the explicit activation of negative stereotypes about aging. In this study, we examined the impact of stereotype threat on recognition memory, with specific interest in (a) the generalizability of previously observed effects, (b) the subjective experience of memory, and (c) the moderating effects of task demands. Older participants subjected to threat performed worse than did those in a nonthreat condition but only when performance constraints were high (i.e., memory decisions had to be made within a limited time frame). This effect was reflected in the subjective experience of memory, with participants in this condition having a lower ratio of "remember" to "know" responses. The absence of threat effects when constraints were minimal provides important boundary information regarding stereotype influences on memory performance.

Previous research has suggested that older and young adults are equally able to regulate their outward expressions of emotion and that the regulation of emotional expression in younger adults results in decreased memory for the emotional stimulus. In the current study, we examined whether older adults show this same memory effect. Older and young adults viewed positive and negative emotional pictures under instructions to view the pictures naturally, enhance their facial expressions, or suppress their facial expressions. Older and young adults showed equivalent outward regulation of expression, but suppressing their emotional expressions led to reduced memory for emotional stimuli only in the young adults. The results suggest that older and young adults are achieving control of their expressions through different mechanisms or strategies.

The ability to imagine hypothetical events in one's personal future is thought to involve a number of constituent cognitive processes. We investigated the extent to which individual differences in working memory capacity contribute to facets of episodic future thought. College students completed simple and complex measures of working memory and were cued to recall autobiographical memories and imagine future autobiographical events consisting of varying levels of specificity (i.e., ranging from generic to increasingly specific and detailed events). Consistent with previous findings, future thought was related to analogous measures of autobiographical memory, likely reflecting overlapping cognitive factors supporting both past and future thought. Additionally, after controlling for autobiographical memory, residual working memory variance independently predicted future episodic specificity. We suggest that when imagining future events, working memory contributes to the construction of a single, coherent, future event depiction, but not to the retrieval or elaboration of event details.