T. W. PAYNE, N. B. Z. STEEGE
without ADHD to match the accuracy of the ADHD students.
This change from set size 4 to 5 indicates a capacity limitation
and overload for the non-diagnosed group, whereas the ADHD
individuals remain the same, with maximum recall at 2. The
data pattern is consistent with the notion that ADHD students
have limitations on verbal rehearsal capacity that are related to
the deficits in attention and sustained effort. The results also
contribute to the concurrent validity of the Reading Span task
as a complex span that is measure sensitive to individual dif-
ferences in the ability to control attention (Engle, 2002), since
there is now evidence of its sensitivity to differences in ADHD
diagnosis.
The visual complex span task appeared to be significantly
more difficult than the verbal assessment for working memory
capacity. As seen in Figure 2, performance is lower for all
participants on the Symmetry Span task, which could explain
the lack of group differences in recall accuracy. Both groups
perform similarly on the memory sets for Symmetry Span, with
separations in performance emerging with set size of 5, but still
not a significant difference (refer to Table 1 for means). This
task may be too challenging to bring out differences in ADHD
status. Additionally, this test came at the end of the battery of
assessments and could be affected by mental fatigue.
The Brown scale scores for reported inattentiveness were not
different for the participant groups, although the difference was
approach statistical significance (p = .058), with the ADHD
group reporting more problems with attention. The Brown scale
is widely used as an indicator of ADHD symptoms, however, it
is only one assessment that is often used in combination with
other measures for the purpose of diagnosis. Previous research
has not always found a relationship with this scale and working
memory measures (Stearns, Dunham, McIntosh, & Dean, 2004),
and it is possible that cognitive performance measures may be
more accurate indicators of ADHD than self-reported behavior.
The main limitation of the research is the small sample size
of the ADHD group (9.8%), which is perhaps unavoidable
when studying college populations in which admittance is de-
pendent upon meeting high academic entry criteria. However,
the findings of this study are theoretically consistent and are
similar to findings with children (Kofler et al., 2010). Revealing
individual differences in cognitive constraints is highly impor-
tant to understanding the intellectual capacity of college stu-
dents in the academic setting, the authors suggest that research-
ers continue to investigate the relationship between working
memory and ADHD at other institutions for comparison to the
results of this study.
The findings of this research provide converging evidence
with previous research with young adult patients and college
students with ADHD indicating lower performance on a variety
of working memory assessments in comparison to those with-
out a diagnosis (Roberts, Millich, & Fillmore, 2012; Torralva et
al., 2013). To put these findings in context, the working mem-
ory measures assess the ability to maintain information in con-
sciousness while alternately engaged in another cognitive activ-
ity. In the reading span task, reading and comprehension judg-
ments happen while trying to additively remember a list of
letters. Memory updating and attempted rehearsal of the letters
occur while one is “distracted” by the reading aspect. Having
this extra cognitive processing reduces the amount of informa-
tion that can be maintained in comparison to having no dis-
tracting activity, regardless of a diagnosis. The findings reveal
hat students with ADHD hold less in memory when engaged in
this dual-task context. The results have implications for situa-
tions in which college students with ADHD are under cognitive
load. Knowledge that problems with working memory in
ADHD individuals extend into college should be integrated
with findings from research on methods to compensate for po-
tential difficulties and understanding factors involved in over-
coming obstacles for these students.
t
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