Task-defined associations are mode specific for selection of relevant dimension but mode independent for selection of location mapping

When compatible and incompatible mappings of a location-relevant task are mixed, or a location-relevant task is mixed with a task for which stimulus location is irrelevant, the benefit of the compatible mapping is eliminated for physical locations and enhanced for location words. Two experiments examined the influence of presenting the location information for the mixed conditions in different stimulus modes (physical location or word). Experiment 1 showed that the effects of mixing location-relevant and location-irrelevant tasks on the spatial compatibility and Simon effects are reduced when the location information is presented in different modes for the two tasks. Experiment 2 showed, in contrast, that the mode distinction had little influence on the effects of mixed compatible and incompatible mappings for location-relevant tasks: The compatibility effect was eliminated for physical locations and enhanced for words, as when there is no mode distinction. Thus, when location is relevant for one task and colour for the other, the task-defined associations of locations to responses are mode specific, but when location is relevant for both tasks, the associations are mode independent.     

No evidence for reduced Simon cost in elderly bilinguals and bidialectals

We explored whether a bilingual advantage in executive control is associated with differences in cultural and ethnic background associated with the bilinguals' immigrant status, and whether dialect use in monolinguals can also incur such an advantage. Performance on the Simon task in older non-immigrant (Gaelic-English) and immigrant (Bengali, Gujarati, Hindi, Malay, Punjabi, Urdu-English) bilinguals was compared with three groups of older monolingual English speakers, who were either monodialectal users of the same English variety as the bilinguals or were bidialectal users of a local variety of Scots. Results showed no group differences in overall reaction times as well as in the Simon effect thus providing no evidence that an executive control advantage is related to differences in cultural and ethnic background as was found for immigrant compared to non-immigrant bilinguals, nor that executive control may be improved by use of dialect. We suggest the role of interactional contexts and bilingual literacy as potential explanations for inconsistent findings of a bilingual advantage in executive control.     

Working memory and access to numerical information in children with disability in mathematics

The relationship among working memory, mathematic ability, and the cognitive impairment of children with difficulties in mathematics was examined. A group of children with difficulties in mathematics (MD) was compared with a group of children with a normal level of achievement matched for vocabulary, age, and gender (N = 49). The children were required to perform a variety of working memory and short-term memory tasks that had been administered 1 year previously. Moreover, the children were asked to perform tasks designed to provide information about speed of articulation. The results suggest a general working memory deficit in children with MD, specifically in the central executive component of Baddeley's model and primarily in the ability to inhibit irrelevant information. However, the MD children were not impaired in speech rate and counting speed tasks, which mainly involve the role of the articulatory loop.     

Combining speed and accuracy to assess error-free cognitive processes

Both the speed and accuracy of responding are important measures of performance. A well-known interpretive difficulty is that participants may differ in their strategy, trading speed for accuracy, with no change in underlying competence. Another difficulty arises when participants respond slowly and inaccurately (rather than quickly but inaccurately), e.g., due to a lapse of attention. We introduce an approach that combines response time and accuracy information and addresses both situations. The modeling framework assumes two latent competing processes. The first, the error-free process, always produces correct responses. The second, the guessing process, results in all observed errors and some of the correct responses (but does so via non-specific processes, e.g., guessing in compliance with instructions to respond on each trial). Inferential summaries of the speed of the error-free process provide a principled assessment of cognitive performance reducing the influences of both fast and slow guesses. Likelihood analysis is discussed for the basic model and extensions. The approach is applied to a data set on response times in a working memory test. The authors wish to thank Roger Ratcliff, Christopher Chabris, and three anonymous referees for their helpful comments, and Aureliu Lavric for providing the data analyzed in this paper.     

Enactment enhances integration between verb and noun, but not relational processing, in episodic memory

Improved recall has consistently been demonstrated following motor activation at encoding (SPT), compared to traditional verbal learning (VT). Enhancements of item-specific processing and relational processing have been proposed as possible mechanisms to account for this SPT effect. There is ample evidence supporting the notion of enhanced item-specific processing, however it is still unclear whether enhancement of relational processing contributes to improved recall. In the present study, 2 experiments were designed to address this issue. In Experiment 1, memory under 2 encoding conditions (VT vs. SPT) and 3 recall conditions (free recall vs. category-cued recall vs. verb-cued recall) were studied in 3 large samples (N= 500-600). Experiment 2 replicated the findings of Experiment 1, and controlled for the use of actual objects, short-term memory effects, and carryover effects, in Experiment 1. The results in both experiments showed an interaction between type of encoding and type of recall. Verb-cued recall was affected differently by SPT encoding, as compared to category-cued recall and free recall. The results indicate that enhanced integration between verb and noun is an effect of SPT encoding, whereas enhanced relational processing is not.     

Activation of adenosine receptors in the posterior cingulate cortex impairs memory retrieval in the rat

Adenosine A1 and A2A receptor agonists and antagonists have been reported to alter learning and memory. The aim of our study was to investigate the involvement of adenosinergic system in memory retrieval into posterior cingulate cortex (PCC) of Wistar rats. To clarify this question, we tested specifics agonist and antagonists of adenosine A1 and A2A receptors in rats submitted to a one-trial inhibitory avoidance task. The stimulation of adenosine A1 and A2A receptors by CPA and CGS21680, respectively, impaired memory retrieval for inhibitory avoidance task, into PCC. These findings provide behavioral evidence for the role of adenosinergic system in the memory retrieval into PCC.     

A Comparison of Least-to-Most Prompts and Progressive Time Delay on the Disruptive Behavior of Students with Autism

We compared the effects of two instructional strategies on the frequency of errors and episodes of disruptive behavior of 4 students with autism. In Phase I, easy and difficult tasks were presented to determine whether the tasks were associated with differential rates of disruptive behavior. Phase II compared the effects of a least-to-most prompting procedure (LTM) to a progressive time delay procedure (PTD) on errors and disruptive behavior when difficult tasks were presented. Observers sequentially recorded instructor instructions, response prompts, prompts for appropriate sitting, and feedback statements; and student disruptive, correct, error, and no responses during 1:1 sessions. Results showed PTD produced fewer errors than LTM for all 4 students, and lower rates of disruptive behavior for 2 students. When PTD was implemented as the final phase with 2 of the students, rates of disruptive behavior associated with the task previously taught with LTM immediately decreased. Conditional probability statements indicated that disruptive behavior occurred infrequently with all 4 students when effective response prompts were used.     

An elicitation method for multiple linear regression models

This paper describes a method of quantifying subjective opinion about a normal linear regression model. Opinion about the regression coefficients and experimental error is elicited and modeled by a multivariate probability distribution (a Bayesian conjugate prior distribution). The distribution model is richly parameterized and various assessment tasks are used to estimate its parameters. These tasks include the revision of opinion in the light of hypothetical data, the assessment of credible intervals, and a task commonly performed in cue-weighting experiments. A new assessment task is also introduced. In addition, implementation of the method in an interactive computer program is described and the method is illustrated with a practical example.     

Protective effect of aerobic fitness on the detrimental influence of exhaustive exercise on information processing capacity

Although aerobic fitness has been thought to protect against the detrimental cognitive effects following exhaustive exercise, available evidence from studies using traditional mean behavioral measures remain somewhat equivocal.PurposeThis study aimed to reconcile this discrepancy by using a novel theory-driven diagnostic tool, the Systems Factorial Technology (SFT).MethodsSixty-six healthy young adults aged from 18 to 30 years old with different levels of aerobic fitness (n = 33 for the higher-fit and lower-fit groups) completed a go/nogo version of redundant-target task before and after a graded exercise test (GXT) until exhaustion. SFT was used to calculate the resilience capacity, which reflects the information processing capacity underlying inhibitory control.ResultsFollowing the GXT, both higher-fit and lower-fit groups showed faster responses while leaving accuracy unchanged as compared to the performance at the pretest. On the other hand, the resilience capacity decreased for the lower-fit group but was maintained for the higher-fit group.ConclusionThe present findings suggest that aerobic fitness may modulate the individual difference in decisional mechanism following exhaustive exercise. In sum, this study offers an alternative mechanistic explanation regarding cognitive individual differences in response to exhaustive exercise and provides novel insights into the significance of maintaining a state of high physical fitness for those who need to perform cognitively challenging tasks under physically stressful conditions (e.g., elite athletes).