Biomedical subjects

André Vandierendonck

Publications and source records attributed to André Vandierendonck.

At least 19 recordsLinked to original sources

PubMed2006

The development of strategy use in elementary school children: working memory and individual differences.

The current study tested the development of working memory involvement in children's arithmetic strategy selection and strategy efficiency. To this end, an experiment in which the dual-task method and the choice/no-choice method were combined was administered to 10- to 12-year-olds. Working memory was needed in retrieval, transformation, and counting strategies, but the ratio between available working memory resources and arithmetic task demands changed across development. More frequent retrieval use, more efficient memory retrieval, and more efficient counting processes reduced the working memory requirements. Strategy efficiency and strategy selection were also modified by individual differences such as processing speed, arithmetic skill, gender, and math anxiety. Short-term memory capacity, in contrast, was not related to children's strategy selection or strategy efficiency.

Age Factors↗

PubMed2006

Input monitoring and response selection as components of executive control in pro-saccades and anti-saccades.

Several studies have shown that anti-saccades, more than pro-saccades, are executed under executive control. It is argued that executive control subsumes a variety of controlled processes. The present study tested whether some of these underlying processes are involved in the execution of anti-saccades. An experiment is reported in which two such processes were parametrically varied, namely input monitoring and response selection. This resulted in four selective interference conditions obtained by factorially combining the degree of input monitoring and the presence of response selection in the interference task. The four tasks were combined with a primary task which required the participants to perform either pro-saccades or anti-saccades. By comparison of performance in these dual-task conditions and performance in single-task conditions, it was shown that anti-saccades, but not pro-saccades, were delayed when the secondary task required input monitoring or response selection. The results are discussed with respect to theoretical attempts to deconstruct the concept of executive control.

Adult↗

PubMed2006

Do working-memory executive components mediate the effects of age on strategy selection or on strategy execution? Insights from arithmetic problem solving.

Younger and older adults performed an inequality verification task (7+6 < 15, Yes/No?) in a control condition and in a dual-task condition where they simultaneously performed an executive-component task. Arithmetic-problem characteristics were manipulated in order to test strategy selection (i.e., choice of appropriate strategies in order to improve performance) and strategy execution (i.e., performance of the cognitive processes involved in each strategy). Results revealed that strategy selection changes with age: Older adults mainly selected one type of strategies in contrast to younger adults who used several types of strategies. These age-related changes were similar in the control and dual-task conditions. Strategy execution also changed with age, as shown by larger age-related differences on hardest problems. These age-related changes were larger in the dual-task condition, compared to the control condition. This impact of executive components as mediator of age-related changes depended on general age-related slowing. We discuss these findings in order to further understand the effects of age on arithmetic performance.

Adult↗

PubMed2006

The role of working memory in carrying and borrowing.

The present study analyzed the role of phonological and executive components of working memory in the borrow operation in complex subtractions (Experiments 1 and 2) and in the carry operation in complex multiplications (Experiments 3 and 4). The number of carry and borrow operations as well as the value of the carry were manipulated. Results indicated that both the number of carry/borrow operations and the value of the carry increased problem difficulty, resulting in higher reliance on phonological and executive working-memory components. Present results are compared with those obtained for the carry operation in complex addition and are further discussed in the broader framework of working-memory functions.

Adult↗

PubMed2006

Selective stopping in task switching: The role of response selection and response execution.

Recently, several studies stressed the role of response selection in cued task switching. The present study tried to investigate directly the hypothesis that no switch cost can be found when there was no response selection. In two experiments, we combined a cued task switching paradigm with the selective stopping paradigm. Results of the experiments demonstrated that a switch cost was found when participants selected a response, even without response execution. Alternatively, when the response was inhibited without the need of response selection, no switch cost was found. These results provide direct evidence for the distinct role of response selection in cued task switching and suggest that response execution is not a necessary factor to obtain a switch cost.

Choice Behavior↗

PubMed2006

Does solution of mental arithmetic problems such as 2 + 6 and 3 x 8 rely on the process of "Memory updating"?

Two experiments are reported that used the selective interference paradigm to study whether, besides response selection, the process of memory updating is involved in simple mental arithmetic. Participants were asked to solve simple sums (e.g., 2 + 6, Experiment 1) or simple products (e.g., 3 X 8, Experiment 2) in a single-task control condition and in three dual-task conditions with a selective interference task, simple reactions, choice reactions, or delayed choice reactions. The role of memory updating was estimated on the basis of the difference in impairment due to the choice reaction time and the delayed choice reaction time task, whereas the difference in impairment between the simple reaction time and the choice reaction time task indicates the role of response selection. While replicating previous results concerning response selection (Deschuyteneer & Vandierendonck, 2005, in press), the study showed that memory updating is strongly involved in solving simple mental arithmetic sums and products.

Adolescent↗

PubMed2006

The effect of interference in the early processing stages on response inhibition in the stop signal task.

In the present study, the relation between interference at the early processing stages and response inhibition was investigated. In previous studies, response stopping appeared to be slowed down when irrelevant distracting information was presented. The purpose of the present study was to further explore the relationship between interference control and response inhibition. In Experiment 1, a stop signal paradigm was combined with a global/local task. The typical global-to-local interference effect is generally attributed to early processing stages, such as stimulus perception and identification. Results of this experiment demonstrated a congruency effect for both reaction time data and stopping performance. In Experiment 2, these results were replicated with a flanker task that used stimulus-incongruent but response-congruent flankers. Results of both experiments suggest that response inhibition and interference at the early processing stages interact.

Female↗

PubMed2006

Tscope: A C library for programming cognitive experiments on the MS windows platform.

Tscope is a C/C+ + programming library designed for programming experiments that run on Windows 2000/XP. It is intended for a public of experimental psychologists with moderate programming skills, who are accustomed to writing their own experimental programs for DOS but have not made the step to Windows-based programming yet. It provides molecular functions for graphics, sound, timing, randomization, and response registration. Together with ANSI-C standard library functions and the powerful C syntax, this set of functions gives the experimenter the opportunity to program virtually any experiment one can come up with. Tscope is completely based on free software, is distributed under the GNU General Public License, and is available at expsy.ugent.be/tscope. An integrated development environment for compiling and running Tscope programs is also freely available.

Cognition↗

PubMed2006

Stimulus- and response-conflict-induced cognitive control in the flanker task.

Recently, several studies have been conducted to investigate the top-down adjustments made after incongruent trials during conflict tasks. In the present study, we investigated conflict monitoring with different types of conflict. In a modified version of the flanker task, a distinction was made between stimulus-stimulus conflict and stimulus-response conflict. Six colors were mapped to three responses in order to exclude all sequences in which a relevant or an irrelevant stimulus- or response-related feature was repeated from trial n-1 to trial n. An analysis of the effect of the congruency of the previous trial demonstrated that conflict adaptation was present. The stimulus congruency effect was reduced after both a stimulus-incongruent trial and a response-incongruent trial. The response congruency effect did not vary as a function of previous congruency. These findings are discussed in relation to the distinction between conflict detection and conflict regulation.

Adult↗

PubMed2005

Duration estimation and the phonological loop: articulatory suppression and irrelevant sounds.

Clock-based theories of time estimation propose that clock pulses are accumulated in working memory. Although these theories do not constrain the form of the memory trace, evidence reported in the literature suggests that active manipulation of a verbal trace may be involved. Four experiments are reported in which participants reproduced or verbally estimated short durations (up to a few seconds) either in a single-task condition or in a condition with a phonological load. Experiments 1, 2 and 4 showed that both interval reproduction and verbal estimation were impaired under concurrent articulatory suppression in comparison to a timing only control condition. Neither irrelevant speech (Experiments 1-3) nor irrelevant tones and music (Experiment 3) impaired timing performance. These findings are taken to show that time estimation is mediated by phonological working memory and the involvement of an active articulatory rehearsal process.

Attention↗

PubMed2005

Effects of stimulus-stimulus compatibility and stimulus-response compatibility on response inhibition.

Previous studies demonstrated that interference control in stimulus-stimulus compatibility tasks slowed down stopping in the stop signal task (e.g., Kramer, A. F., Humphrey, D. G., Larish, J. F., Logan, G. D., & Strayer, D. L. (1994). Aging and inhibition: beyond a unitary view of inhibitory processing in attention. psychology and aging, 9, 491-512). In the present study, the impact of stimulus-stimulus compatibility and stimulus-response compatibility on response inhibition is further investigated. In Experiment 1, the stop signal task was combined with a traditional horizontal Simon task and with a vertical variant. For both dimensions, stopping responses was prolonged in incompatible trials, but only when the previous trial was compatible. In Experiment 2, the Simon task was combined with a spatial Stroop task in order to compare the effects of stimulus-stimulus and stimulus-response compatibility. The results demonstrated that both types of compatibility influenced stopping in a similar way. These findings are in favor of the hypothesis that response inhibition in the stop signal task and interference control in conflict tasks rely on similar mechanisms.

Attention↗

PubMed2005

Blunted prefrontal perfusion in depressed patients performing the Tower of London task.

Impairment of cognition is common in depression, and many tasks on which depressed patients are impaired are sensitive to frontal lobe dysfunction. Performance on the Tower of London (TOL) task, which includes setting up and maintaining multiple subgoals at the same time, has been shown to depend on intact prefrontal cortices. Single photon emission computed tomography (SPECT) with 99mTc-ethyl cysteinate dimer was used to compare cognitive activation in nine depressed patients and nine normal controls during performance of the TOL task. Planning times and accuracy were measured as performance parameters, and functional imaging data were analysed with statistical parametric mapping (SPM99) to determine significant voxel-wise differences in activation between the two groups. During activation, depressed patients were as accurate as controls but differed in that they spent more thinking time. These findings agree with the results of neuropsychological studies. Compared with the normal controls, depressed patients were characterized by a blunted perfusion response in the right middle frontal cortex [Brodmann area (BA) 6] and the left superior frontal gyrus (BA 9), and by increased perfusion in the right superior temporal gyrus (BA 21) and the insular cortex (BA 13). This study shows that a SPECT activation procedure using the TOL task under classical test conditions is feasible in depressed patients.

Adult↗

PubMed2005

Visuo-spatial processing in Parkinson's disease: evidence for diminished visuo-spatial sketch pad and central executive resources.

A dual-task study compared the visuo-spatial sketch pad and central executive components of working memory as potential cognitive mechanisms of visuo-spatial dysfunction in Parkinson's disease. Mildly to moderately affected Parkinsonian patients (n = 15) and controls (n = 15) performed the Corsi blocks task concurrently with tasks designed to load on the visuo-spatial sketch pad (spatial tapping) or the central executive (random interval repetition). Patients performed more poorly in both concurrent task conditions, implicating a reduction in both visuo-spatial sketch pad and central executive resources. The impact of the concurrent tasks varied with disease severity, with the central executive deficit prominent at disease onset, but the visuo-spatial sketch pad deficit becoming apparent only in the moderate stages of the illness.

Aged↗

PubMed2005

The odd-even effect in addition: an analysis per problem type.

The odd-even effect is a well documented finding in the literature on mental arithmetic, at least for multiplication. It implies that false answers with the same parity as the correct answer are rejected more slowly than false answers with a different parity. For addition, this effect is not so well documented. The study by Krueger and Hallford (1984) is the only one that investigated odd-even effects for addition. However, they did not investigate odd-even effects per problem, even though there are indications that problem type can modulate odd-even effects for multiplication (Lemaire & Reder, 1999). Therefore, we wanted to get more insight into odd-even effects for addition by investigating odd-even effects per problem type. Our results extended the findings of Krueger and Hallford. First of all, we found an interaction between split and problem type. The most important and new result of present study, however, was a strong parity effect for E + E problems. We discuss our results in terms of two alternative explanations for odd-even effects, namely use of a parity rule on the one hand and familiarity with even outcomes on the other.

Adolescent↗

PubMed2005

Inhibiting responses when switching: Does it matter?

In the present study, cued task-switching was combined with the stop-signal paradigm in order to investigate the interaction between response inhibition and task-switching. In line with earlier findings from Schuch and Koch (2003), the results show that switch and repetition trials following inhibited responses were processed equally fast. This confirms the hypothesis of Schuch and Koch (2003) that after signal-inhibit trials there is less interference, resulting in a disappearance of the switch cost. Furthermore, stopping performance was not affected by task-switching. The estimated stop-signal latencies were similar for switch and repetition trials, while the stop-signal delays were longer for switch compared to repetition trials. This result suggests that response inhibition and the inhibition processes in cued task-switching are not relying upon a common mechanism.

Cognition↗

PubMed2005

The phonological loop in task alternation and task repetition.

It has recently been proposed that task repetition is easier than task alternation because the appropriate task settings are already present in working memory, whereas during task alternation task settings must be retrieved from long-term memory (Mayr & Kliegl, 2000). The present study tested whether the phonological loop is involved in keeping the relevant task settings active in working memory. It may then be expected that concurrent articulatory suppression would diminish the facilitation associated with task repetition because the phonological loop could no longer maintain the appropriate task settings active in working memory. Both during task repetition and task alternation the relevant task settings should then be retrieved from long-term memory. Three dual-task experiments were conducted. The results of Experiment 1 were in support of our prediction. Experiment 2 replicated the findings of Experiment 1 and showed that the task settings probably represent the adequate response mappings. Experiment 3 ruled out the involvement of the visuo-spatial sketchpad and more general coordination demands during dual tasking.

Attention↗

PubMed2005

Gap effect in reflexive and intentional prosaccades.

The analysis of saccadic eye movements has assumed an important role as a pathophysiological approach in neuropsychiatric diseases. However, before abnormal cognitive saccade behavior can be fully understood, some basic psychophysiological aspects have to be further investigated. Previous studies have demonstrated a shortening of saccade latency when the fixation stimulus was removed prior to the appearance of a peripheral visual target. This gap effect is smaller for antisaccades (AS; away from the target) than for reflexive saccades (RS; towards the target). Apart from the generation of an intentional eye movement, AS rely on different processes including reflex inhibition and spatial reversal of the saccade direction. We wondered whether intentional prosaccades (IpS) that do not rely on these additional processes also show a reduced gap effect. Therefore, we compared the gap effect in a saccade paradigm for RS and IpS in healthy subjects. We found a smaller gap effect in IpS than in RS and suggest that this reduction reflects endogenous strategic processes. Our findings further imply that reflex inhibition is not the unique cause for the smaller gap effect in AS than in RS and suggest that an endogenous component may be involved. We hypothesize that frontal control on the superior colliculus fixation cell activity may continue even after the fixation stimulus has disappeared, thus inhibiting a fixation offset and reducing the gap effect.

Aged↗

PubMed2005

Response selection involves executive control: evidence from the selective interference paradigm.

In the present study, we investigated whether response selection involves executive control, using the selective interference paradigm within Baddeley's (1986) working memory framework. The interference from response selection was estimated by comparing the patterns of dual-task interference of simple and choice RT tasks with those of a number of established working memory tasks. In Experiment 1, we compared impairment of forward and backward verbal serial recall from the RT tasks and articulatory suppression. Experiment 2 measured the adverse effects of the RT tasks and matrix tapping on forward and backward visuospatial serial recall. Finally, in Experiment 3, we examined the impairment from the RT tasks with two measures of executive control--namely, letter and category fluency. Altogether, the three experiments demonstrated that response selection interferes with executive control and that the interference is not produced at the level of working memory's slave systems, which supports the assumption of executive involvement in response selection.

Choice Behavior↗