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Previous studies showed that phonological short-term and working memory spans are related to vocabulary and grammar learning in children learning a second language. Typically, short-term storage, as measured by simple span tasks such as non-word repetition, are connected to vocabulary learning. Grammar learning is generally linked to the working memory system. This system is often tested by complex span tasks that require participants to process and store information simultaneously. Yet, few studies have investigated the role of both memory mechanisms in native and foreign vocabulary and grammar learning longitudinally. The current study determines whether phonological short-term and verbal working memory spans contribute differentially to the acquisition of vocabulary and grammar in Dutch as a first language (L1) and in English as a foreign language (EFL). The participants for this study are monolingual Dutch children (N = 138), in grades 4 and 5 (aged 9;0-11;0), learning EFL in the classroom. An L1 and an EFL non-word repetition task were used to measure phonological short-term memory and verbal working memory was measured with a backward digit span task. Receptive vocabulary and production of grammatical knowledge was measured in Dutch and in English, as well as receptive grammar in English. The data indicated that when the same children are longitudinally followed in both L1 and EFL, only past performance is important for L1 vocabulary learning. Phonological short-term memory does not contribute to L1 vocabulary. As expected, working memory span significantly predicts L1 grammar learning. For EFL vocabulary learning, past performance is most important; L1 vocabulary has a smaller but independent role and in line with previous research, phonological short-term memory also has an independent role. For both receptive and productive EFL grammar learning, contrary to expectations, working memory span did not play a role. In contrast, EFL phonological short-term memory had a small but independent role for receptive grammar learning. EFL vocabulary had a similar role for receptive and productive grammar, which was stronger than EFL phonological short-term memory for receptive grammar. However, past performance had the largest role for both types of grammar learning. In sum, when looking at the initial stages of EFL in a formal setting, we only found a role for working memory span in L1 grammar but not in EFL. Phonological short-term memory only had a role in EFL vocabulary and receptive grammar learning, and was language specific. In all, the current data show that in addition to phonological short-term memory, past performance on vocabulary and grammar contributed significantly to vocabulary and grammar learning and that the role of vocabulary and phonological short-term memory and working memory span in grammar learning is language specific.

Young and older adults' control of saccadic eye movements was compared using an antisaccade task, which requires the inhibition of a reflexive saccade toward a peripheral onset cue followed by an intentional saccade in the opposite direction. In 2 experiments, an age-related decline was found in the suppression of reflexive eye movements, as indicated by an increased proportion of saccades toward the cue, and a longer time needed to initiate correct antisaccades. The results from Experiment 2 suggested that older adults' slower antisaccades may be explained partly in terms of increased failures to maintain the cue-action representation at a sufficient activation level. The results suggest that the notion of selective preservation with age of the ability to inhibit spatial responses does not apply to the active inhibition of prepotent spatial responses.

Background: Individuals with intellectual disabilities (ID) are characterised by inhibition deficits; however, the magnitude of these deficits is still subject to debate. This meta-analytic study therefore has two aims: first to assess the magnitude of inhibition deficits in ID, and second to investigate inhibition type, age, IQ and the presence/absence of comorbid problems as potential moderators of effect sizes. Method: Twenty-eight effect sizes comparing ID and age matched normal controls on inhibition tasks were included in a random effects meta-regression. Moderators were age, IQ, inhibition type and presence/absence of comorbid disorder. Results: The analysis showed a medium to large inhibition deficit in ID. Inhibition type significantly moderated effect size, whereas age and comorbid disorder did not. IQ significantly moderated effect size indicating increasing effect size with decreasing IQ, but only in studies that included a sample of ID participants with mean IQ > 70. The analysis indicated comparable deficits in behavioural inhibition and interference control, but no significant deficits in cognitive inhibition and motivational inhibition. Conclusions: These results indicate that ID is characterised by a medium to large inhibition deficit in individuals with ID. ID seems not to be characterised by deficits in cognitive and motivational inhibition, which might indicate that distinct processes underlie distinct inhibition capacities.

We investigated how proactive and reactive control facilitates performance in mixed stimulus-response compatibility (SRC) tasks. SRC effects were eliminated in mixed tasks and reversed following incompatible trials. In mixed tasks, early preferential response activation was present in stimulus-locked lateralized readiness potentials (LRPs) but reduced following incompatible trials. In event-related potentials (ERPs), stimulus-locked N2 was enhanced in all mixed trials but was not significantly influenced by the preceding trial. A response-locked fronto-central negative component (N-120), peaking just before the response, was largest for mixed compatible trials preceded by incompatible trials. This N-120 was paired with an enhancement to the peak of the response-locked LRP. Proactive control is involved in selection of an S-R mapping via the indirect route of a dual-route model. Reactive control corrects the S-R mapping, particularly when alternating between S-R mappings.

The amplitude and latency of single-trial EEG/MEG signals may provide valuable information concerning human brain functioning. In this article we propose a new method to reliably estimate single-trial amplitude and latency of EEG/MEG signals. The advantages of the method are fourfold. First, no a-priori specified template function is required. Second, the method allows for multiple signals that may vary independently in amplitude and/or latency. Third, the method is less sensitive to noise as it models data with a parsimonious set of basis functions. Finally, the method is very fast since it is based on an iterative linear least squares algorithm. A simulation study shows that the method yields reliable estimates under different levels of latency variation and signal-to-noise ratioÕs. Furthermore, it shows that the existence of multiple signals can be correctly determined. An application to empirical data from a choice reaction time study indicates that the method describes these data accurately.

Background: The goal of this study is to evaluate the effectiveness of a computerised working memory (WM) training on memory, response inhibition, fluid intelligence, scholastic abilities and the recall of stories in adolescents with mild to borderline intellectual disabilities attending special education. Method: A total of 95 adolescents with mild to borderline intellectual disabilities were randomly assigned to either a training adaptive to each child's progress in WM, a non-adaptive WM training, or to a control group. Results: Verbal short-term memory (STM) improved significantly from pre- to post-testing in the group who received the adaptive training compared with the control group. The beneficial effect on verbal STM was maintained at follow-up and other effects became clear at that time as well. Both the adaptive and non-adaptive WM training led to higher scores at follow-up than at post-intervention on visual STM, arithmetic and story recall compared with the control condition. In addition, the non-adaptive training group showed a significant increase in visuo-spatial WM capacity. Conclusion: The current study provides the first demonstration that WM can be effectively trained in adolescents with mild to borderline intellectual disabilities.

Background: The ability to inhibit motor responses, as assessed by the stop-signal reaction time (SSRT), is impaired in children and adolescents with attention-deficit/hyperactivity disorder (ADHD). However, the between-study variation in effect sizes is large. The aim of this study was to investigate whether this variability can be explained by between-study variation in Go task complexity. Method: Forty-one studies comparing children or adolescents diagnosed with ADHD to normal control subjects were incorporated in a random-effects meta-regression analysis. The independent variables were a global index of Go task complexity (i.e., mean reaction time in control subjects [RTc]) and a more specific index (i.e., spatial compatibility of the stimulus-response mapping). The dependent variable was the SSRT difference between ADHD and control subjects. Results: The SSRT difference increased significantly with increasing RTc. Moreover, the SSRT difference was significantly increased in studies that employed a noncompatible, that is, arbitrary, mapping compared with studies that incorporated a spatially compatible stimulus-response mapping. Conclusions: These results indicate that inhibitory dysfunction in children and adolescents with ADHD varies with task complexity: inhibitory dysfunction in ADHD is most pronounced for spatially noncompatible responses. Explanations in terms of inhibition and working memory deficits and a tentative neurobiological explanation are briefly discussed.

Feedback processing is an important aspect of cognitive control and decision-making. Several studies have shown that heart rate slows following feedback that indicates incorrect performance or loss of money. The current study was the first to investigate (1) whether this slowing reflects an evaluation of the valence of the outcome or a system that indicates that the feedback contains informative value, (2) whether the slowing is determined by the value of the outcome relative to the range of possible outcomes, and (3) whether highly anxious individuals have a hypersensitive feedback monitoring system. The results showed that heart rate only slows when the feedback is performance based. The information provided by negative feedback is processed in a context-sensitive manner, suggesting that heart rate slowing following feedback reflects a signal associated with informative value for subsequent performance adjustment. Highly anxious individuals showed larger heart rate slowing in response to feedback indicating high stakes, but they failed to respond to feedback in a context-sensitive manner. These results were interpreted to suggest that anxious individuals are generally more sensitive to performance outcomes. Heart rate changes following informative feedback proved to be a sensitive index of component processes associated with performance monitoring.

he relation between event-related brain activity, age, and intelligence was studied using a visual oddball task presented longitudinally to girls at 9, 10, and 11 years of age. The event-related brain potential (ERP) components showed typical gradual decrements in latency and amplitude with increasing age, but there were also nonlinear changes in event-related brain activity with age. Regression analyses between Raven's intelligence scores and latency of the ERP components showed negative correlations for the late endogenous components at age 9. At ages 10 and 11, the earlier components showed positive correlations while the later components continued to show negative correlations. The amplitude measures showed only positive correlations and these correlations shifted from the exogenous PI component at age 9 towards the later endogenous components at ages 10 and 11. The present findings suggest a qualitative shift in the relation between event-related brain activity and intelligence between 9 and 10 years of age. (PsycINFO Database Record (c) 2003 APA, all rights reserved)(journal abstract)

The integration of behavioral processes with changes in vagally-controlled heart rate has been the focus of our investigations. A series of studies is reviewed showing that central and peripheral response inhibition is a primary source of transient, vagally-induced cardiac slowing during information processing. Individual differences in such responses are then shown to relate to the amplitude of cardiovascular responses to stressors. Overall, the specificity and sensitivity of vagal responses to higher level cortical function is supported by our research. (PsycINFO Database Record (c) 2003 APA, all rights reserved)(journal abstract)

Comments on the article by B. Fowler et al (see record 2000-15213-005) in which they observed that nitrous oxide, an inhalation anaethetic, does not interact with experimental manipulations derived from the additive factors literature. They proposed a 2-tiered cognitive-energetical model to account for the apparent "exhaustive additivity." This model assumes that nitrous oxide affects a lower tier resulting in a non-selective effect on an upper tier, which is comprised of energetic mechanisms that are selectively linked to processing stages. In this commentary, it is argued that the "exhaustive additivity" can easily be accommodated by linear stage models. The findings of Fowler et al suggest a new stage rather than a new model. Moreover, their new model seems to predict "exhaustive interaction" rather than "exhaustive additivity." It is concluded that Fowler et al may have a highly interesting finding, but not for the reasons they submitted when accounting for the "exhaustive additivity" displayed by nitrous oxide. (PsycINFO Database Record (c) 2000 APA, all rights reserved)