IS DIGIT SUPERIORITY INDISPENSABLE WITH REGARD TO SHORT TERM MEMORY SPAN?

It is known that digits have a positive effect on the performance of short term memory (STM) span and it is called the digit superiority effect. This study aims to examine the effect of familiar stimuli (digits, colors, digit names, color names, and words) on STM span. In order to measure STM capacity, a memory span task was used including the digit, word, and color span lists. 91 participants (44 female, 47 male) aged between 18-27 (M = 21,43, SD = 1.50) participated in the study that consisted of three different experiments. Results of Experiment 1 revealed that there was a significant difference between the digit name and word with regard to span size and total span. In Experiment 2 and 3, the main effect of familiar stimulus type on total span and span size was significant, and also the difference between all types of stimuli was significant (Experiment II, digit name>word=color name; Experiment III, digit>digit name>color name>color). The common result obtained from all experiments is that digits are superior with regard to STM span than other familiar stimuli types such as words, color names, colors. This study confirmed that digit superiority effect is indispensable on verbal and visual STM span. Keywords Digit superiority, short term memory, memory span

Doubts About the Role of Rehearsal in the Irrelevant Sound Effect

The irrelevant sound effect (ISE) describes the disruption of processes involved in maintaining information in working memory (WM) when irrelevant noise is present in the environment. While some posit that the ISE arises due to split obligation of attention to the irrelevant sound and the to-be-remembered information, others have argued that background noise corrupts the order of information within WM. Support for the latter position comes from research showing that the ISE appears to be most robust in tasks that emphasize ordered maintenance by a serial rehearsal strategy, and diminished when rehearsal is discouraged or precluded by task characteristics. This prior work confounds the demand for seriation with rehearsal. Thus, the present study aims to disentangle ordered maintenance from a rehearsal strategy by using a running memory span task that requires ordered output but obviates the utility of rehearsal. Across four experiments, we find a significant ISE that persists under conditions that should discourage the use of rehearsal and among individuals who self-report use of alternative strategies. These findings indicate that rehearsal is not necessary to produce an ISE in a serial recall task and thus fail to corroborate accounts of the ISE that emphasize the involvement of rehearsal.

Consolidation and reconsolidation of visual and semantic memory in Parkinson’s disease

Cognitive and mnestic impairments have a significant negative impact on the quality of parkinsonian patients’ life. Memory impairment causes changes in the mechanisms of information processing. The aim of this study was to investigate the characteristics of transformations undergone by memorized visual and semantic content during memory consolidation and reconsolidation in patients with Parkinson’s disease. The study was conducted on 32 male patients with PD (ICD code: G20). Among the patients, 9 had rigidity/bradykinesia-d ominant PD, 11 had tremor-dominant PD, and 12 suffered from a mixed type of PD. Short-term memory span was assessed using the 10 words and the visual memory tests proposed by Luria. As stimulus materials we used a symbolic representation of the old Greek letter resembling an owl and a translated excerpt from a Canadian aboriginal epic. Regardless of the PD form, the quality of the memorized information was either altered or completely lost. The mechanisms underlying such transformations differed quantitively depending on the PD form. Transformation of the memorized information occurred in the conditions of both incidental and deliberate memorization and was represented by distortions (substitution of the original content with confabulations) and simplifications of the structural and semantic organization. We consolidated significantly lesser amount of auditory verbal (р = 0.018) and visual (p = 0.029) information. This trend was consistent with the pronounced distortion of content during its retrieval.

The Effects of a Novel Non-catechol Dopamine Partial Agonist on Working Memory in the Aged Rhesus Monkey

Aged-related declines in cognition, especially working memory and executive function, begin in middle-age and these abilities are known to be mediated by the prefrontal cortex (PFC) and more specifically the dopamine (DA) system within the PFC. In both humans and monkeys, there is significant evidence that the PFC is the first cortical region to change with age and the PFC appears to be particularly vulnerable to age-related loss of dopamine (DA). Therefore, the DA system is a strong candidate for therapeutic intervention to slow or reverse age related declines in cognition. In the present study, we administered a novel selective, potent, non-catechol DA D1 R agonist PF-6294 (Pfizer, Inc.) to aged female rhesus monkeys and assessed their performance on two benchmark tasks of working memory – the Delayed Non-match to Sample Task (DNMS) and Delayed Recognition Span Task (DRST). The DNMS task was administered first with the standard 10 s delay and then with 5 min delays, with and without distractors. The DRST was administered each day with four trials with unique sequences and one trial of a repeated sequence to assess evidence learning and retention. Overall, there was no significant effect of drug on performance on any aspect of the DNMS task. In contrast, we demonstrated that a middle range dose of PF-6294 significantly increased memory span on the DRST on the first and last days of testing and by the last day of testing the increased memory span was driven by the performance on the repeated trials.

From aMCI to AD: The Role of Visuo-Spatial Memory Span and Executive Functions in Egocentric and Allocentric Spatial Impairments

A difficulty in encoding spatial information in an egocentric (i.e., body-to-object) and especially allocentric (i.e., object-to-object) manner, and impairments in executive function (EF) are typical in amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD). Since executive functions are involved in spatial encodings, it is important to understand the extent of their reciprocal or selective impairment. To this end, AD patients, aMCI and healthy elderly people had to provide egocentric (What object was closest to you?) and allocentric (What object was closest to object X?) judgments about memorized objects. Participants' frontal functions, attentional resources and visual-spatial memory were assessed with the Frontal Assessment Battery (FAB), the Trail Making Test (TMT) and the Corsi Block Tapping Test (forward/backward). Results showed that ADs performed worse than all others in all tasks but did not differ from aMCIs in allocentric judgments and Corsi forward. Regression analyses showed, although to different degrees in the three groups, a link between attentional resources, visuo-spatial memory and egocentric performance, and between frontal resources and allocentric performance. Therefore, visuo-spatial memory, especially when it involves allocentric frames and requires demanding active processing, should be carefully assessed to reveal early signs of conversion from aMCI to AD.

Locomotion and Topographical Working Memory in Children With Myelomeningocele and Arthrogryposis Multiplex Congenita

Background: In children with myelomeningocele (MMC) and arthrogryposis multiplex congenital (AMC), adequate rehabilitation measures are accessible with the goal of attaining the utmost motor development. However, there is a lack of knowledge as to how children develop navigation utilizing their locomotion abilities. The aim of the present study was to explore topographic working memory in children with MMC and AMC.Methods: For this purpose, we assessed 41 children with MMC and AMC, assigned an ambulation group, and 120 typical developing (TD) children, with mean ages of 11.9, 10.6, and 9.9 years, respectively. All groups performed a topographic working memory test while moving in a walking space and a visuospatial working memory test in a reaching space. Children with MMC and AMC also performed a test to measure their ability to reason on visuospatial material, Raven's Coloured Progressive Matrices.Results: The topographic working memory span was shorter in the MMC group than in the TD group. In general, all ambulation groups had a shorter topographic working memory span than the TD group. The visuospatial working memory span was shorter in the non-ambulation group than in the TD group. Scores from the visuospatial reasoning test were lower in the non-ambulation group than in the community ambulation group.Conclusions: Even though a higher cognitive score was found in the community ambulation group than in the non-ambulation group, topographic working memory was affected similarly in both groups. Including children who develop community ambulation in therapy programs containing aspects of navigation may gain even children with low levels of MMC and AMC. These results evidenced the importance of motor development and navigational experience gained through direct exploration of the environment on topographic memory.

EFL Reading Fluency Development and Its Effects

<p>Speed reading courses have been considered an effective method to improve learners' reading rate. Research in this area has concentrated on the effect of a speed reading course on students' speed improvement, but not on how to structure the course or the effects of speed improvement on other aspects of language and other types of reading. This thesis, in the first place, deals with the issue of scheduling a speed reading course, in terms of lesson frequency and course length, to achieve the best effect. The thesis also seeks to determine if speed development in the course leads to rate improvement in reading texts outside the course. Finally, the thesis looks at the effects of speed improvement on oral reading rate, language accuracy and language complexity. In the first of two experiments, a speed reading course was delivered to the four experimental groups, who followed the course on different scheduling. Four scoring methods were used to measure the participants' speed improvement and it was found that one group made smaller increases than the others in all scoring methods. A pre-test and a post-test for reading other types of texts were administered and the speeds on these texts by the four treatment groups were compared with those by the control group. The results demonstrated that all but one group from the treatment category outperformed the control group. The second experiment was both a replication of the first experiment in order to confirm the reliability of the first experiment's results and an expansion from the first experiment to explore other issues. It involved two control groups, one of which followed the usual English program at the university and two treatment groups, one of which received consultation sessions during the treatment. The results on speed increases within the speed reading course corroborate the findings in the first experiment. Reading rate transfer from the speed reading course to other texts was significant (p<.001). Comparisons within the treatment groups and within the control groups demonstrated that the usual English program did not noticeably affect the speed increase transfer to other texts, oral reading fluency improvement, or language memory span development, but the consultation sessions substantially affected speed improvement in the course and speed improvement on other types of texts. With respect to oral reading rate the experiment found that the difference between the control groups and the treatment groups was statistically significant (p<.05). The relationships between reading fluency, language accuracy, and language complexity were also explored by looking at the comprehension scores and memory span results. It was found that reading fluency improvement does not necessarily negatively affect comprehension. It, however, does not assist language accuracy development to a remarkable degree. More importantly, the experiment showed that the treatment groups considerably expanded their memory span, which implies that reading speed improvement facilitates language complexity. High correlations between speed increases in the speed reading course, reading rate improvement in other types of texts and memory span development were also found.</p>

EFL Reading Fluency Development and Its Effects

<p>Speed reading courses have been considered an effective method to improve learners' reading rate. Research in this area has concentrated on the effect of a speed reading course on students' speed improvement, but not on how to structure the course or the effects of speed improvement on other aspects of language and other types of reading. This thesis, in the first place, deals with the issue of scheduling a speed reading course, in terms of lesson frequency and course length, to achieve the best effect. The thesis also seeks to determine if speed development in the course leads to rate improvement in reading texts outside the course. Finally, the thesis looks at the effects of speed improvement on oral reading rate, language accuracy and language complexity. In the first of two experiments, a speed reading course was delivered to the four experimental groups, who followed the course on different scheduling. Four scoring methods were used to measure the participants' speed improvement and it was found that one group made smaller increases than the others in all scoring methods. A pre-test and a post-test for reading other types of texts were administered and the speeds on these texts by the four treatment groups were compared with those by the control group. The results demonstrated that all but one group from the treatment category outperformed the control group. The second experiment was both a replication of the first experiment in order to confirm the reliability of the first experiment's results and an expansion from the first experiment to explore other issues. It involved two control groups, one of which followed the usual English program at the university and two treatment groups, one of which received consultation sessions during the treatment. The results on speed increases within the speed reading course corroborate the findings in the first experiment. Reading rate transfer from the speed reading course to other texts was significant (p<.001). Comparisons within the treatment groups and within the control groups demonstrated that the usual English program did not noticeably affect the speed increase transfer to other texts, oral reading fluency improvement, or language memory span development, but the consultation sessions substantially affected speed improvement in the course and speed improvement on other types of texts. With respect to oral reading rate the experiment found that the difference between the control groups and the treatment groups was statistically significant (p<.05). The relationships between reading fluency, language accuracy, and language complexity were also explored by looking at the comprehension scores and memory span results. It was found that reading fluency improvement does not necessarily negatively affect comprehension. It, however, does not assist language accuracy development to a remarkable degree. More importantly, the experiment showed that the treatment groups considerably expanded their memory span, which implies that reading speed improvement facilitates language complexity. High correlations between speed increases in the speed reading course, reading rate improvement in other types of texts and memory span development were also found.</p>

Effects of methylphenidate on reinforcement learning depend on working memory capacity

Rationale Brain catecholamines have long been implicated in reinforcement learning, exemplified by catecholamine drug and genetic effects on probabilistic reversal learning. However, the mechanisms underlying such effects are unclear. Objectives and methods Here we investigated effects of an acute catecholamine challenge with methylphenidate (20 mg, oral) on a novel probabilistic reversal learning paradigm in a within-subject, double-blind randomised design. The paradigm was designed to disentangle effects on punishment avoidance from effects on reward perseveration. Given the known large individual variability in methylphenidate’s effects, we stratified our effects by working memory capacity and trait impulsivity, putatively modulating the effects of methylphenidate, in a large sample (n = 102) of healthy volunteers. Results Contrary to our prediction, methylphenidate did not alter performance in the reversal phase of the task. Our key finding is that methylphenidate altered learning of choice-outcome contingencies in a manner that depended on individual variability in working memory span. Specifically, methylphenidate improved performance by adaptively reducing the effective learning rate in participants with higher working memory capacity. Conclusions This finding emphasises the important role of working memory in reinforcement learning, as reported in influential recent computational modelling and behavioural work, and highlights the dependence of this interplay on catecholaminergic function.

Effects of Depressed Mood on Syllogistic Reasoning: The Buffering Role of High Working Memory Span

Previous research provided consistent evidence for the existence of the unique cognitive limitation in depressed mood: the impairment of the construction of mental models. In the current research, we applied the classical paradigm using categorical syllogisms to examine the relationship between depressed mood and integrative reasoning, aiming at gathering research evidence on the moderating role of the operation span of working memory. Specifically, we examine the hypothesis that high working memory capacity is a buffering variable and acts as a protective factor preventing the negative impact of depressed mood on syllogistic reasoning. A categorical syllogism, in the simpler evaluative form, consists of two premises (that are assumed to be true) and a conclusion that is to be evaluated as valid (when it follows logically from the premises) or invalid (when it does not follow from the premises). In the cover story, we informed participants that they would read about some observations carried out in a normal garden (believable conclusions) versus in a garden with radical genetic transformations (unbelievable conclusions) in order to stimulate the emergence of belief bias. The participants were 115 high school students who filled out the BDI scale and completed the OSPAN task. In line with predictions, there were main effects of depressed mood and operation span on the accuracy of performance (worse performance in the group with a high in comparison to a low level of depressed mood and much worse performance in low compared to high OSPAN participants). The analyses yielded a strong interaction effect of Depressed mood × OSPAN × Conflict. For participants with high levels of working memory capacity, there were no limitations related to a high level of depressed mood in syllogistic reasoning. On the other hand, a different pattern emerged for participants with low working memory span. In this group, participants with a high level of depressed mood in comparison to those with a low level of depressed mood showed much higher limitations in syllogistic reasoning, especially in reasoning concerning conflict syllogisms. We discuss the implications of this research for recent therapeutic programs using computerized cognitive tasks aimed at individuals with a high level of depressed mood.