Many parents have observed that their child with ADHD stays attentive and engaged during ‘high interest’ activities, e.g., while playing video games, but has considerable problems staying focused on less inherently engaging tasks, e.g., doing schoolwork. This discrepancy in attention during preferred and non-preferred activities has led some to speculate that children with ADHD don’t have underlying neurocognitive deficits that explain their attention difficulties, but that they simply don’t try as hard when they are not interested or motivated.
Surprisingly, there has been little research to document this observation. And, if differences in attention for children with ADHD during preferred and non-preferred activities were found, would this reflect deficits in important neurocognitive processes rather than their just not trying as hard when they are not interested?
The New Study
Those questions were addressed in the study titled Inattentive behavior in boys with ADHD during classroom instruction: the mediating role of working memory processes, published recently in the Journal of Abnormal Child Psychology.
Participants were 62 8–12 year-old boys, including 32 with a confirmed diagnosis of ADHD. Each participant watched two 10-minute video clips: one was an instructional math video that presented age-appropriate math information the way a teacher might and the other was an action-packed sequence from a Star Wars movies.
Boys were videotaped while watching each clip so the percent of time they attended to each video could later be determined. This measure of visual attention was made by trained observers who did not know whether the boys were in the ADHD or comparison group.
Working memory — Working memory (WM) is the cognitive system responsible for the temporary storage and manipulation of information; WM plays an important role in both learning and focusing attention. Considerable research has documented that many individuals with ADHD have WM deficits and that this contributes to difficulties associated with the disorder. In fact, some researchers — including the authors of this study — hypothesize that the core symptoms of ADHD are secondary to WM deficits. They argue that it is when a child’s WM capacity is exceeded that problems with attention and hyperactivity become evident.
A simple example illustrates the importance of WM for particular academic tasks. Try adding 3 and 9 in your head. That was probably easy. Now, trying adding 33 and 99. That was probably more difficult. Finally, try adding 333 and 999. This is quite challenging for most adults even though each calculation required is easy. The challenge occurs because you need to store information — the sum of 3+9 in the one’s column and then in the ten’s column — as you process the remaining part of the problem, i.e., 3+9 in the hundred’s column. Most people find that this strains their WM capacity; and, if your WM capacity is exceeded, you could not complete the problem. It is not hard to imagine how children whose WM skills are substantially below their peers would struggle in the classroom and how this could be manifest as inattentive behavior.
In addition to having boys watch the videos, the researchers carefully measured their WM skills. This enabled the researchers to test whether any differences in attention they found between boys with and without ADHD during the 2 videos was related to differences in their WM. They predicted that:
1. Attention during the Star Wars video would not differ for boys with and without ADHD.
2. Boys with ADHD would display poorer attention during the Math Instruction video. This is because the WM demands to follow along what is presented in the WM are significantly greater than what is required in the Star Wars video
3. The drop in attention during the Math Instruction video for boys with ADHD would be explained by their poorer WM skills.
Thus, the researchers sought to document parents’ long-standing observation that attention problems in their child with ADHD are most evident during less interesting tasks, and, that inattention during such tasks reflects deficits in specific neurocognitive processes, i.e., WM capacity, rather than a motivational deficit, e.g., laziness.
Results from this study were consistent with prior research and supported the authors’ hypotheses. Specifically, they found that:
1. As documented in prior studies, boys with ADHD had specifically lower WM scores than comparison boys.
2. During the Star Wars video, there was no difference in the percent of time that boys in each group were paying attention.
3. Although attention in both groups of boys dropped during the Math Instruction video, it dropped by significantly more in boys with ADHD, i.e., by 16% compared to only 7%. They note that based on guidelines for recommended daily math instructional time for 3rd-5th graders, a 16% decrement in attention during daily math instruction is equal to missing roughly 29 math lessons across the school year. 4. Over half of the attention differences between boys with and without ADHD during the Math Instruction videos was explained by WM differences between the groups. In other words, when WM differences between the groups was accounted for, differences in attention during the math video declined by more than half. Thus, there was evidence that deficits in this important neurocognitive function is an important contributor to the attention deficits that youth with ADHD often display during classroom instruction.
Summary and implications
Results from this study validate the observation made by many parents that attention problems for children with ADHD are far more likely to be evident in some contexts than others, i.e., during non-preferred but not during preferred tasks. As demonstrated in this study, the gap in attention between boys with and without ADHD clearly emerges during instructional activities that require sustained attention. This gap was sufficiently large to help explain why children with ADHD would master fewer math skills across an academic year.
Study findings also support the important role of WM in explaining why attention deficits emerge during instructional tasks. The math video required greater WM capacity to follow along, and the authors demonstrated over half the drop in attention for the boys with ADHD during the math video was accounted for by their poorer WM. They argue that this indicates that youth with ADHD show attention problems in some contexts but not others because of a specific neurocognitive deficit, and not because they are less motivated to engage in tasks that don’t interest them.
What are the intervention implications of these findings? First, one could design classroom and instruction techniques that reduce the WM demands on children with low WM ability. While this makes good sense, positive effects of compensatory classroom interventions remain to be clearly demonstrated. Second, one could work to train WM skills directly. There has been substantial research done on working memory (WM) training and positive results in a number of individual studies have been reported. However, compelling evidence that WM training yields clinically meaningful improvement in outcomes related to classroom instruction and academic achievement is not yet available. Thus, this is an area where ongoing efforts to develop effective interventions is needed.
There are limitations of this study to note. First, the sample was exclusively male and subsequent work is needed to confirm whether a similar patterns of results is obtained with females. Second, the authors acknowledge that in addition to differing in WM demands, the 2 videos differed on other dimensions that could impact children’s attention, e.g., the rapidity in which scenes changes, the level of visual imagery and sounds, etc. They note that subsequent work should vary the level of WM demands within videos that are equally engaging visually. This would help to more clearly determine whether WM demands are the key factor related to the emergence of inattentive behavior in some contexts but not others.
– Dr. David Rabiner is a child clinical psychologist and Director of Undergraduate Studies in the Department of Psychology and Neuroscience at Duke University. He publishes the Attention Research Update, an online newsletter that helps parents, professionals, and educators keep up with the latest research on ADHD, and helped prepare the self-paced, online course How to Navigate Conventional and Complementary ADHD Treatments for Healthy Brain Development.
The Study in Context
- When 1 + 1 = 5: Dyscalculia and Working Memory
- What are cognitive abilities and how to boost them?
- Study shows why children with ADHD should be reevaluated each year: Attention problems perceived by teachers are far less stable than we imagine
- Study: Rates of ADHD diagnosis and medication treatment continue to increase substantially
- Study: Don’t overlook sleep difficulties in children with ADHD; they may impair functioning as much as ADHD itself