فصلنامه روانشناسی شناختی

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Since working memory capacity (WMC) predicts individual differences in the wide range of abilities, this experiment tested the effect of WMC on time perception in preschool children.
At first, 108 children’s working memory capacity were measured by CANTAB tests and then 21 children with high working memory capacity and 20 children with low working memory capacity were assigned. Then, both groups performed two reproduction tasks they instructed to reproduce 700 and 3000 millisecond intervals in mono task, and to reproduce 3000 ms with a performing concurrent non-temporal task as a dual task. Data analyzed by mixed design ANOVA and post hoc tests. Results showed that in mono task, accuracy of high WMC was better than the low WMC group. In dual task, although there was no significant difference in the accuracy of reproduction task, children with high WMC had better performance in non-temporal task. Furthermore, children with low WMC were more variable performance than high WMC in all intervals.
 

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working memory is the comprehensive cognitive system that embedded attentional and memorical mechanisms and therefore can be used in systematic research of cognitive problems. The aim of this study was to investigate the predictive role of working memory capacity and executive functions (shifting, inhibition and updating) for Obsessive Compulsive Disorder.  We selected 164 student   (90 male and 74 female)    from university of Tehran with random sampling method  and they completed Maudsley Obsessional – Compulsive Inventory (Hodgson & Rachman, 1977), the Digit Backward Span Task (workingmemory capacity), Forward Span task (Short Term Memory), Stroop (inhibition, Spreen & Strauss, 1998), Set- Switching Task (shifting, Rogers & Monsell, 1995) and Keep Track Task (updating, Martinez, et al., 2011). Data analyzing used regression showed working memory and executive function totally predict considerable amount (67 percent) of obsessive compulsive predisposition. Therefore it can be concluding, obsessive people have crucial weakness in storage, monitoring and executive cognitive function (in general attention control) and we can use training in these functions as treatment strategies.

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Obesity is one of the most important problems which threatens the global health. Healthcare organizations spend a
large amount of money to predict and treat obesity every year. The most common treatment for obesity is
concentrated on shaping a new lifestyle with more exercise and healthy diet. But a multitude of dieters fail. In this study, the role of cognitive processing in dieters` success or fail was investigated. Participants were
successful (N= 42) and unsuccessful (N= 45) dieters between 18 and 40 years old. Attentional bias, positive
implicit association, and working memory capacity were measured by dot-probe task, a modified
version of implicit association test (IAT), and N-Back task. Results indicated that unsuccessful dieters showed
greater attentional bias to (d= 0.69) and more food preferences for (d= 1.06) high-calorie food pictures.
Nevertheless, there was no significant difference in implicit associations for high calorie food and in working memory capacity between the groups. These results were congruent with some previous studies and they were discussed based on dual-processing model.
 

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Abstract
Working memory is the comprehensive cognitive system that embedded attentional and memorial mechanisms and therefore can be used in systematic research of cognitive problems. Accordingly, the aim of this study was to investigate the developmental changes of working memory capacity, and its components, including phonological loop, visuospatial sketchpad, and central executive (inhibition and updating). A total of 356 children (8 and 12 years) recruited from primary school in Tehran were selected and tested. Digit Span, and the Kim Karad Visual Memory Test were used for measuring phonological loop and visuospatial sketchpad. Working memory capacity was measured by Backward Digit Span, and finally, the Stroop Task, and the Keep Track task measured central executive. Data analyzing showed as child growth, working memory and its components become more effective. More skills in arithmetic abilities, more flexibility in storage and processing, more experience in academic achievement and more use of metacognitive strategies can be possible reasons for the results of this study.

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Abstract
The aim of this study was to investigate the role of working memory capacity and errorless and errorful practice on the learning the relative timing was a motor task. 50 Participants based on were selected aged 22±4 years as accessible samples randomly assigned to one of four groups (errorless low working memory capacity, errorful low working memory capacity, errorless high working memory, errorful high working memory capacity). This study was carried out in four phases. First phase (pre-test), subjects participated in 10 trials without knowledge of results (KR) on four-segment timing task. In the acquisition(ACQ) phase, a timing task with three different difficulty levels (simple, moderate, and difficult) was practiced in three sessions of 45 trials with feedback by experimental groups, except for control. In the 10-minute and 24 hour retention and 10- minute transfer tests, errorless group with low working memory capacity and errorful group with high working memory capacity had better performance than other groups. In the dual task tests (24-hour transfer) errorless group with low working memory capacity in the relative timing (intermediate times, RMSE) had better performance than other groups. These results indicate that the efficiency and efficacy of errorless and errorful practice interact with psychological indicators such as working memory capacity. These results suggest that implicit motor learning (errorless) may be beneficial for children with working memory capacity. Individual with high working memory capacity might benefit from learning explicitly (errorful). Results in dual task conditions support the implicit learning and reinvestment theories.