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Abstracts of Recent Publications
Bugg, J. M.,
DeLosh, E. L., & Clegg, B. A.
(in press). Physical activity moderates time-of-day
differences in older adults’ working memory performance. Experimental Aging
Research. Based on a synthesis of
the literature on time of day and physical fitness effects on cognition,
the current study examined whether physical activity moderated time-of-day
differences in older adults’ performance on a working memory task.
Sedentary older adults’ working memory performance declined
significantly from morning to evening, whereas more active older adults
performed similarly across the day. This interaction did not extend to
performance on a simple reaction time task. A novel explanation based on
the selective effect of mental fatigue on executive control processes is
proposed.
Bugg, J. M., DeLosh, E. L., Davalos, D. B., & Davis, H. P. (in press). Age differences
in Stroop interference: Contributions of general
slowing and task-specific deficits. Aging, Neuropsychology,
and Cognition. This study examined the contributions of general
slowing and task-specific deficits to age-related changes in Stroop interference. 938 participants aged 20 to 89
years completed an abbreviated Stroop
color-naming task and a subset of 281 participants also completed
card-sorting, simple reaction time, and choice reaction time tasks.
Age-related increases in incongruent color-naming latency and card-sorting perseverative errors were observed. Hierarchical
regression analyses showed that the processing speed measures accounted for
significant variance on both dependent measures, but that there was also a
significant residual effect of age. An additional regression analysis
showed that some of the variance in incongruent color-naming, after
controlling for processing speed, was shared with the variance in perseverative errors. Overall, findings suggest that
the age difference in Stroop interference is
partially attributable to general slowing, but is also attributable to
age-related changes in task-specific processes such as inhibitory control.
Bugg, J. M., Zook, N. A., DeLosh, E. L., Davalos, D. B., & Davis, H. P. (in press). Age
Differences in Fluid Intelligence: Contributions of General Slowing and
Frontal Decline. Brain and Cognition.
The current study examined the contributions of general slowing and frontal
decline to age differences in fluid intelligence. Participants aged 20 to
89 years completed Block Design, Matrix Reasoning, simple reaction time,
choice reaction time, Wisconsin Card Sorting and Tower of London tasks.
Age-related declines in fluid intelligence, speed of processing, and
frontal function were observed. Hierarchical regression analyses showed
that the processing speed and frontal function measures accounted for
significant variance in fluid intelligence performance, but there was also
a residual effect of age after controlling for each variable individually
as well as both variables. An additional analysis showed that the variance
in fluid intelligence that was attributable to processing speed was not
fully shared with the variance attributable to frontal function. These
findings suggest that the age-related decline in fluid intelligence is due
to general slowing and frontal decline, as well as other unidentified
factors.
Carpenter, S. K., & DeLosh, E. L. (in press). Impoverished cue
support enhances subsequent retention: Support for the elaborative
retrieval explanation of the testing effect. Memory & Cognition.
Three experiments investigated the role of transfer-appropriate
processing and elaborative processing in the testing effect. Experiment 1
examined whether the magnitude of the testing effect reflects the match
between intervening and final tests by factorially
manipulating the type of intervening and final tests. Retention was not
enhanced for matching relative to mismatching intervening and final tests,
contrary to the transfer-appropriate processing view. Experiment 2 examined
final retention as a function of the number of cues needed to retrieve
items on intervening cued recall tests. In this case, fewer retrieval cues
were associated with better memory on the final test. Experiment 3 replicated
the findings of Experiment 2 while controlling for individual item
difficulty and directly manipulating the number of cues present. These
findings suggest that an intervening test may be most beneficial to final
retention when it provides more potential for elaborative processing.
Merritt, P. S., DeLosh, E. L., &
McDaniel, M. A. (in press). Effects of word frequency on individual-item
and serial-order retention: Tests of the order-encoding view. Memory & Cognition. The order encoding
view of the word-frequency effect proposed that low-frequency (LF) items
attract more attention to the encoding of individual-item information than
high-frequency (HF) items, but at the expense of order encoding (DeLosh
& McDaniel, 1996). When combined with the assumption that free recall
of unrelated words is organized according to their original order of
presentation, this view explains the finding that HF words are better
recalled than LF words in pure lists, but in mixed lists recall is better for
LF words. The present study confirmed that in mixed lists order memory
becomes equivalent for HF and LF words, and that
the predicted pattern of order memory and recall holds for incidental
order-encoding conditions, for longer lists than used in previous
experiments, and for lists with minimal inter-item associativity.
Moreover, recall from HF lists declined but recall from LF lists improved
in related-word lists relative to unrelated-word lists, reversing the usual
pure-list free-recall advantage for HF words. These results were uniquely
predicted by the order-encoding account and favor this view over
accessibility, inter-item association, and cueing effectiveness
explanations of the word-frequency effect.
Carpenter, S. K., & DeLosh, E. L. (2005). Application of the
testing and spacing effects to name learning. Applied Cognitive
Psychology, 19, 619-636. Four experiments investigated the
effects of testing and spacing on the learning of face-name
stimulus-response pairs. Experiments 1a and 1b compared the recall of names
following intervening tests versus additional study opportunities and found
that testing produced better retention of names. Experiments 2 and 3
explored the effects of repeated tests versus study for massed, uniform, or
expanded spacing intervals. Tested names were better retained than studied
names, spaced names were better retained than massed names, and memory was
best for items tested at spaced intervals. Contrary to past findings,
expanded schedules did not yield better memory than uniform schedules in
either experiment. Theoretical implications for the testing and spacing
effects are discussed, along with effective name-learning techniques based
on these principles.
Zook, N. A., Davalos, D. B.,
DeLosh, E. L., Davis, H. P. (2004). Working memory, inhibition, and fluid
intelligence as predictors of performance on Tower of Hanoi and London
tasks. Brain and Cognition, 56, 286-292. The
contributions of working memory, inhibition, and fluid intelligence to
performance on the Tower of Hanoi (TOH) and Tower of London (TOL) were
examined in 85 undergraduate participants. All three factors accounted for
significant variance on the TOH, but only fluid intelligence accounted for
significant variance on the TOL. When the contribution of fluid intelligence
was accounted for, working memory and inhibition continued to account for
significant variance on the TOH. These findings support Duncan, Burgess,
and Emslie’s (1995) argument that fluid
intelligence contributes to executive functioning, but also show that the
executive processes elicited by tasks vary according to task structure.
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