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Variation in the ability to maintain internal goals while resolving competition from multiple information streams has been related to individual differences in working memory capacity (WMC). In a multitask environment, task choice and task performance are influenced by internal goals, prior behavior within the environment, and the availability of relevant and irrelevant information in the environment. Using the voluntary task-switching procedure, task performance, as measured by switch costs, was related to WMC, but only at short preparation intervals. Task choice processes were only weakly related to WMC. These findings are consistent with models of cognitive control that separate task choice processes from the processes of activating and maintaining task readiness. WMC is related to regulation of specific task parameters but not to choice processes integral to the coordination of multiple sources of information.Keywords Working memory capacity . Task switching . Choice processing Mechanisms of cognitive control are central to optimal multitasking performance (Brown, Reynolds, & Braver 2007;Logan, 1985;Monsell, 2003). Cognitive control must be exerted in a multitask environment because the environment affords multiple behavioral paths and does not specify which task should be completed at any given moment. Guiding the completion of one task in the face of competition from other potential tasks requires the selection and activation of the task set, or group of component cognitive operations, necessary to carry out that task (Rogers & Monsell, 1995). The goal to perform a given task must be maintained and shielded from interference from other goals potentially applicable in the environment (De Jong, 2000). In addition, as the current task changes, no-longer-relevant task sets are deactivated (Mayr & Keele, 2000). This type of sequential control requires flexible updating and maintenance of the task rules. Different components of cognitive control are referred to as executive control, executive attention, or working memory.The demands of a multitasking environment-maintaining goals in the face of competition and distraction and updating goals as the environment changes-are functions that have been attributed to working memory. More specifically, measures of working memory capacity (WMC) are thought to tap the same set of functions. For example, WMC has been defined as "the attentional processes that allow for goaldirected behavior by maintaining relevant information in an active, easily accessible state outside of conscious focus, or to retrieve that information from inactive memory, under conditions of interference, distraction, or conflict" (p. 23; Kane, Conway, Hambrick, & Engle 2007). Individual differences in WMC are correlated with the abilities to resolve interference between memory representations (Rosen & Engle, 1998); to filter out distracting information (Conway, Cowan, & Bunting 2001); to act on the current task goal when habitual attentional orienting may lead to inaccurate responding, as in ...

Quizzing improves retention compared to additional study opportunities, a phenomenon known as test-enhanced learning. Two experiments investigated whether the type of question at quiz improves retention for factual and applied course material on exams in an online college course. Students were given quizzes with either factual questions or questions designed to encourage application of a particular concept. As expected, quizzing with feedback improved exam performance compared to material that had not been quizzed. Further, the benefits of quizzing transferred to different question types. Performance on application exam questions improved if students were quizzed with factual questions. Likewise, performance on factual exam questions improved if students were quizzed with application questions. These results replicate the finding that quizzing benefits retention in an online learning environment and, more importantly, that the benefits of quizzing transfer to exam questions that differ in type from the quiz question.

The roles of verbal short-term memory (vSTM) in task selection and task performance processes were examined when individuals were asked to voluntarily choose which of two tasks to perform on each trial randomly. Consistent with previous voluntary task-switching (VTS) research, we hypothesized that vSTM would support random task selection by maintaining a sequence of previously executed tasks that would be used by a representativeness heuristic. Furthermore, because using a representativeness heuristic requires sufficient time for updating and comparison processes, we expected that vSTM would have a greater effect on task selection when more time was available. Participants completed VTS under concurrent articulatory suppression and foot tapping at short and long response-to-stimulus intervals (RSIs). Task selection in VTS was more repetitive under suppression than under foot tapping, but this effect did not vary with RSI, suggesting that vSTM does not maintain the sequence of executed tasks to guide task selection. Instead, vSTM is critical for maintaining the intended task and ensuring that it is carried out. In contrast to the finding that a working memory load impairs task performance, we found no difference in reaction times and no switch costs between suppression and foot-tapping conditions, suggesting that vSTM is not critical for task performance.

Task choice processes in older (60+ years) and younger (18-30 years) adults were compared using a voluntary task switching procedure (Arrington & Logan, 2004). To assess age-related differences in task representation maintenance, preparation times were varied across a large range of response-to-stimulus intervals (100, 500, 1,000, and 5,000 ms) and the environmental influence on task selection was varied by repeating or changing stimuli from trial to trial. Older adults switched less frequently than younger adults and this effect was the same at each RSI. Younger adults were more likely to switch tasks when the stimulus changed than when it repeated suggesting that they used a different process to determine task choices, either endogenous task selection or environmentally supported task repetitions. Older adults' task selection was unaffected by stimulus repetitions indicating that they were less flexible with the processing they used to guide task selection. These findings are consistent with previous observations of age-related increases in goal shielding, but not with age-related deficits in task goal maintenance. Robust age differences in switch costs were observed across RSIs suggesting that task reconfiguration processes are different following endogenous than exogenous task selection.