Aging and Sustained Attention

This week we look into the effects that age has on mind wandering and sustained attention.

          Lin, Hsiao, & Chen (1999) used the Continuous Performance Test (CPT) to study sustained attention development in primary school aged children.  The CPT measures sustained attention deficits caused by cognitive inhibition and has been used in the past to measure  sustained attention deficits in children with ADHD as well as those at risk for schizophrenia.  The reasoning behind this is that in those at high risk for schizophrenia, there will be certain brain regions that are not being activated during the CPT.   Previous CPT studies have been rather limited in scope and therefore this study was useful as it tested a large sample of children of both genders.  They found that CPT performance improves in children between the ages of 6 and 15, particularly between the ages of 6 and 12.  This finding suggests that the cognitive inhibition aspect of sustained attention develops during this age range.  

      Carriere et al. (2010) studied a larger age span (20-70) to examine sustained attention over age and time.  By looking across decades, they were able to find that both SART errors and response speed decreased with age in an overall linear trend (see Figure 1). More specifically, they found that measures of task disengagement on the SART decreased rapidly in early adulthood (~3^rd decade), following which they remained rather stable despite the increasing of age (See Figure 2).  The differences between that of Figure 1 and Figure 2 suggest that SART error and RT (Figure 1) explain different aspects of performance that that of the task disengagement measured in this study (RTCT, anticipations, & omissions; Fig. 2).  

The findings on task disengagement suggest that sustained ability does not change as a function of aging but rather as a function of maturation early in adulthood but then remains stable with further aging.  The decreased response time of older adults may reflect the use of a more strategic response style that leads to a reduction in SART errors. There are a couple of possibilities for why this might be the case.  According to Jackson & Balota (2011), older adults are higher in conscientiousness compared to younger adults.  This could have an impact this difference of mind-wandering seen in age difference.  Carriere et al. conclude with an important point, which is that had they not chosen such a large age range and looked only at those in the second decade compared to the seventh, for example, it would have looked as if sustained attention continuously improves with age.  However, by looking across each decade, we are able to see that it actually remains generally unchanged following the 3^rd decade. 

       This idea of effect of the design and chosen sample of study is important to note in the work by Lin, Hsiao, & Chen.  Unlike the other articles, where Carriere et al. found no gender effect (while Jackson & Balota (2011) only test female subjects), Lin, Hsiao, & Chen found that sex was also associated with performance on the degraded CPT, with girls performing worse than boys in hit rate and sensitivity.  However they note that this gender effect changes depending on the version of CPT used which also reinforces the importance of comparing findings which have used comparable methods.  

          Using versions of SART followed by a probed reading comprehension task (noting that this was a more realistic measure), Jackson & Balota (2011) found that not only do older adults not mind wander more than younger adults, they actually tend to mind wander less.  When using an easier version of the SART, older adults responded at a slower pace and were more accurate than younger adults.  In addition, older adults had an increase in response time following an error, which indicates that they had an increased difficulty reengaging in the task after making an error. Older adults were higher in conscientiousness while they also rated the tasks as both more difficult and more interesting than younger adults.  Interest in task may be an important predictor of performance. The researchers do comment that for older adults, as opposed to college students, conducting this novel experimental context on a college campus may contribute to their reported decreased mind-wandering.  I found this point interesting as I would expect that this could actually have an opposite effect, in that perhaps bringing these older adults onto a college campus could create a nostalgic effect in which they mind wander more, to their experiences when in college.  This however would have caused an increase in mind-wandering.  Another thought that this point then brought me to is the idea that perhaps the participation itself in a psychological study is a novel experience for older adults, whereas nowadays it is so common to conduct studies using undergraduate students, that these undergraduate participants may participate in many of these experiments and therefore may not find the act of participating as exciting as older adults new to such an experience may find it.  If so, this aspect of participating in an experiment may contribute to why older adults reported the task as more interesting.  If this is the case, it would be expected that older adults would generally rate tasks as more interesting/engaging over a wider variety of tasks compared to younger adults.  However, regardless of what it was that made the experiment more engaging and interesting for older adults, the idea that the extent of task interest may be an important age-related difference in understanding observed effects.

            In comparing their work to that of Carriere et al. (2010) Jackson & Balota note an important point that “…their study used a version of the SART consistent with Robertson et al. (1997), and thus can only be directly compared with Experiment 1 of the present study” (p.116).  I think this is a very important point because it is easy to just compare the findings of different studies on mind wandering, however, it is important to take into account the actual methods used in such studies which could account for any discrepancies between findings.