A number of studies have suggested that attentional control skills required to perform 2 tasks concurrently become impaired with age (A. A. Hartley, 1992; J. M. McDowd & R. J. Shaw, 2000). A. A. Hartley (2001) recently observed that the age-related differences in dual-task performance were larger when the 2 tasks required similar motor responses. The present study examined the extent to which age-related deficits in dual-task performance or time sharing--in particular, dual-task performance of 2 discrimination tasks with similar motor requirements--can be moderated by training. The results indicate that, even when the 2 tasks required similar motor responses, both older and younger adults could learn to perform the tasks faster and more accurately. Moreover, the improvement in performance generalized to new task combinations involving new stimuli. Therefore, it appears that training can substantially improve dual-task processing skills in older adults.

Older adults' difficulties in performing two tasks concurrently have been well documented (Kramer & Madden, 2008). It has been observed that the age-related differences in dual-task performance are larger when the two tasks require similar motor responses (Hartley, 2001) and that in some conditions older adults also show greater susceptibility than younger adults to input interference (Hein & Schubert, 2004). The authors recently observed that even when the two tasks require motor responses, both older and younger adults can learn to perform a visual discrimination task and an auditory discrimination task faster and more accurately (Bherer et al., 2005). In the present study, the authors extended this finding to a dual-task condition that involves two visual tasks requiring two motor responses. Older and younger adults completed a dual-task training program in which continuous individualized adaptive feedback was provided to enhance performance. The results indicate that, even with similar motor responses and two visual stimuli, both older and younger adults showed substantial gains in performance after training and that the improvement generalized to new task combinations involving new stimuli. These results suggest that dual-task skills can be substantially improved in older adults and that cognitive plasticity in attentional control is still possible in old age.Address correspondence to Louis Bherer, Department of Psychology, Université du, Québec à Montréal (UQÀ M), Case postale 8888, succursale Centre-ville, Montréal, Québec, Canada, H3C 3P8. bherer.louis@uqam.ca. NIH Public Access NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptIn the past few years, many studies have examined the effect of practice on dual-task performance in order to better understand the basic cognitive mechanisms underlying dualtask performance. Some researchers have observed large practice effects on dual-task performance but without evidence of parallel execution of concurrent tasks (Ruthruff, Johnston, & Van Selst, 2001). Others have reported that practice enables participants to perfectly share their attention between two concurrent tasks (Schumacher et al., 2001). Moreover, substantial interindividual differences in the ability to coordinate two tasks have been observed. In fact, Ruthruff, Van Selst, Johnston, and Remington (2006) showed evidence of parallel execution of concurrent task (bottleneck bypass) in some participants. Furthermore, a dual-task deficit is also frequently observed in older adults, a group that manifests larger interindividual variability than younger adults. Both types of evidence, practice effects in younger adults and age-related deficits in dual-task performance, suggest that dual-task performance relies upon attentional control strategies. This implies that training and learning an optimal strategy could help to improve dual-task performance (Meyer & Kieras, 1997).Several studies have shown that indeed dual-task training can lead to substantially enhanced performance in...

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Results identify behavioral correlates and potential risks of mind wandering that might enable efforts to detect and mitigate driver inattention.

It is well known that conversation (e.g., on a cell phone) impairs driving. We demonstrate that the reverse is also true: Language production and comprehension, and the encoding of the products of comprehension into memory, are less accurate when one is driving. Ninety-six pairs of drivers and conversation partners engaged in a story-retelling task in a driving simulator. Half of the pairs were older adults. Each pair completed one dual-task block (driving during the retelling task) and two single-task control blocks. The results showed a decline in the accuracy of the drivers' storytelling and of their memory for stories that were told to them by their nondriving partners. Speech production suffered an additional cost when the difficulty of driving increased. Measures of driving performance suggested that the drivers gave priority to the driving task when they were conversing. As a result, their linguistic performance suffered.