Aging of attention: Does the ability to divide decline?

Abstract

The basic question motivating the present research was whether there were age-related differences in the ability to perform two concurrent tasks above and beyond the ability to perform the tasks in isolation. One reason why this question is of interest stems from Baddeley's (e.g., 1986Baddeley's (e.g., , 1992 Baddeley, Logie, Bressi, Della Sala, & Spinnler, 1986) hypothesis that the ability to coordinate two concurrent tasks is a function ofa central executive in a working memory system, and that the efficiency or effectiveness of the central executive might decline with increased age. The plausibility of this proposal would obviously decrease iffew or no age differences were found in dual-task performance after taking single-task performance into account. Accordingly, a major purpose of the present study was to attempt to assess the effectiveness of the hypothesized executive independently of performance in the constituent tasks.Another reason why the influence of age on the relationship between single-and dual-task performance is of interest is that it is related to a larger issue concerning the extent to which age differences in complex cognitive activities are predictable from age differences found in the performance of elementary cognitive tasks. That is, an important consideration in research on aging and cognition is the level at which age-related influences are manifested. One possibility is that there are direct and independent age-related effects on both simple and complex cognitive activities, suggesting that higher order cognitive processes are more affected by age-related influences than are lower ordero or elementary, processes. An alternative possibility is that all of the age-related influ- Previous research has yielded conflicting results regarding the relationship between adult age and the ability to divide attention between two concurrent tasks. At least some of the inconsistency is probably attributable to methodological variations, such as the manner in which divided-attention ability has been assessed, how single-task performance has been considered, and the degree of control over relative emphasis placed on each task. TWo experiments employing procedures sensitive to these concerns were conducted in which a speeded decision task was performed during the retention interval of a letter-memory task. The results of both experiments indicated that there were relatively few age-related influences on dual-task performance vis-i-vis those on single-task performance.

Effect of age on forward and backward span tasks

“…The results of the present study confirm the general expectation that verbal and visuospatial span performance decline with increasing age, and support previous research indicating that working memory declines with increasing age (Baeckman et al, 2000;Botwinick & Storandt, 1974;Fisk & Warr, 1996;Gregoire & Van der Linden, 1997;Salthouse et al, 1995;Vecchi & Cornoldi, 1999). It was noted that spatial span in general demonstrated greater agerelated decline than digit span.…”

“…Nevertheless, even using a processing speed explanation of aging, it has been acknowledged that older adults have been found to be especially disadvantaged when required to perform complex or multiple tasks within a restricted time, because there are more cognitive components to be slowed (Salthouse, 1996a). Furthermore, much of the evidence for an age-related decline in central executive performance is based on dual task methodology (McDowd & Shaw, 2000;Salthouse et al, 1995). However, Della Sala and Logie (2001) argue that a number of these findings may have resulted from combining constituent tasks on which an age-related decrement was already evident.…”

Obstacle negotiation kinematics: age-dependent effects of postural threat

“…Additionally, cognitive changes such as dementia, altered mental status, and decreased information processing capacity and speed are also associated with aging (Salthouse, Fristoe, Linewater, & Coon, 1995). It is now well accepted that these intrinsic changes alter the ability of older adults to maintain balance and thus contribute to an increased risk and number of fall occurrences (Alexander, 1994).…”

Effect of normal aging on the manipulation of information in working memory

“…For example, a ceiling effect in young subjects but not in older ones might be responsible for the detection of an interaction. One solution proposed to resolve the problem of unequal baselines is to manipulate the conditions oftesting to ensure comparable levels ofperformance in both groups (Belleville, Malenfant, Peretz, & Chatelois, 1992;Meudell & Mayes, 1982;Salthouse, 1985;Salthouse, Fristoe, Lineweaver, & Coon, 1995;Somberg & Salthouse, 1982).…”