Carmen Flores-Mendoza

Working memory and intelligence

Abstract The correlation perspective shows that working memory (WM) is strongly related to psychometric intelligence. Although there are numerous psychometric abilities, there is a powerful single source of variance, namely, g . g Is evidenced by the positive correlation between all psychometric cognitive abilities. The construct of WM distinguishes contents (verbal, numerical, spatial) and operations (storage and processing). However, some studies found a high correlation between several diverse WM tasks, which supports the construct validity of the concept of WM as one general cognitive resource. This study explores the structure of WM drawing on the methodology of intelligence structure research. Then, WM is related to intelligence. One hundred and eighty-seven participants took part in the study. WM was assessed through eight computerized tasks, while intelligence was assessed through the Raven Matrices or the PMA-R. The results show that WM can be considered as one general cognitive resource and that this resource is strongly related with intelligence ( r =+0.7). The statement that there is something underlying WM and intelligence is discussed.

Influence of psychosocial factors on the development of sleep bruxism among children

BACKGROUND Bruxism is described as an orofacial parafunction that affects both children and adults. The maintenance of the childhood habit into adulthood may compromise health. As there are few studies on this issue, there is a need for further research on sleep bruxism among children. AIM The aim of this study was to assess the prevalence of sleep bruxism in children and the influence of psychosocial factors. METHODS A cross-sectional study was carried out on 652 randomly selected children aged 7-10 years at public and private schools in Belo Horizonte, Brazil. The instruments used were: questionnaire for parents, Child Stress Scale, and the scales on neuroticism and responsibility from the prevalidated Big Five Questionnaire for Children. Psychological tests were administered and evaluated by psychologists. Sleep bruxism among children was reported by parents. The Social Vulnerability Index from the city hall database was used to determine the social classification of the families. The chi-squared test, binary and multivariate logistic regressions were used, with the significance level set at 5%. RESULTS A 35.3% prevalence of bruxism was found. No association was found between bruxism and stress, gender, age, or social vulnerability. The adjusted logistic model determined that children with high levels of neuroticism (OR = 1.9, CI 1.3-2.6) and responsibility (OR = 2.2, CI 1.0-5.0) are twice as likely to have the habit of sleep bruxism when compared to those who have low levels of these personality traits. CONCLUSIONS A high degree of responsibility and neuroticism, which are individual personality traits, are determinant factors for the development of sleep bruxism among children.

The real relationship between short-term memory and working memory

Storage-oriented memory span tasks with no explicit concurrent processing are usually referred as short-term memory (STM) tasks, whereas tasks involving storage plus concurrent processing requirements are designated as working memory (WM) tasks. The present study explores a question that remains unsolved: Do STM and WM tasks clearly tap distinguishable theoretical constructs? For that purpose, a large sample of 403 participants was tested through 12 diverse memory span tasks. Half of those tasks are widely accepted as measures of STM, whereas the other half measure WM. The results show that STM and WM share largely overlapping underlying capacity limitations, suggesting that all memory span tasks tap essentially the same construct. Some implications are discussed.

Generational changes on the draw-a-man test: a comparison of Brazilian urban and rural children tested in 1930, 2002 and 2004.

Although gains in generational intelligence test scores have been widely demonstrated around the world, researchers still do not know what has caused them. The cognitive stimulation and nutritional hypotheses summarize the several diverse potential causes that have been considered. This article analyses data for a sample of 499 children tested in 1930 and one equivalent sample of 710 children tested 72 years later, the largest gap ever considered. Both samples comprised children aged between 7 and 11 who were assessed by the Draw-a-Man test in the city of Belo Horizonte, Brazil. Further, one additional sample of 132 children was assessed in 2004 in a rural area very similar in several diverse factors to the 1930 urban sample. The results are consistent with both the cognitive stimulation and the nutritional hypotheses.

Inteligencia y memoria de trabajo: la relación entre factor g, complejidad cognitiva y capacidad de procesamiento

La psicologia experimental ha estudiado extensivamente las caracteristicas de la memoria, mientras que la psicologia correlacional ha actualizado las principales propiedades de la inteligencia. El acercamiento entre ambos enfoques se basa en el analisis de las relaciones entre un concepto nuclear de la memoria ¾ la memoria de trabajo ¾ y el principal ingrediente del concepto psicometrico de inteligencia ¾ el factor g. Las evidencias disponibles sugieren que las diferencias individuales en g podrian ser explicadas por los conceptos cognitivos de capacidad y de velocidad asociados a la memoria de trabajo. Esas evidencias sugieren nuevos modos de mejorar la inteligencia ¾ y, por tanto, los correlatos asociados a ella ¾ a traves del incremento de la capacidad del sistema para procesar informacion de manera eficiente.Experimental psychology has studied memory characteristics extensively meanwhile correlational psychology has analyzed the main properties of intelligence. The approach between both viewpoints are based on memory nuclear concept analysis -working memory and, the main intelligence psychometrical concept - g factor. The available data suggests that individual differences concern to the g could be explained by cognitive concepts like span and speed linked to working memory. These data suggests new procedures to improve intelligence - and therefore the social aspects associated to it - by increasing system capacity of efficient information processing.

Relationship between Tasks Performed, Personality Traits, and Sleep Bruxism in Brazilian School Children - A Population-Based Cross-Sectional Study

Background Tasks can be instruments of stress and may affect the health of children. Sleep bruxism is a multifactorial sleep-related movement disorder that affects children and adults. The aim of the present study was to analyze the association between children’s tasks, personality traits and sleep bruxism. Methods And Findings A cross-sectional, population-based study of 652 randomly selected Brazilian schoolchildren (52% of whom were female), aged from 7 to 10 years was conducted in the city of Belo Horizonte, Brazil. A questionnaire based on criteria proposed by the American Academy of Sleep Medicine (AASM) was completed by parents. In addition, the Neuroticism and Responsibility sub-scales of the Big Five Questionnaire for Children (BFQ-C) were administered to the children. Psychological tests were administered and evaluated by psychologists. The Social Vulnerability Index from the city council database was used to determine the social classification of the families. Chi-square and Poisson regression statistical tests were used with a 95% confidence interval. The majority of families were classified as having low social vulnerability (61.3%), whereas, 38.7% were classified as having high social vulnerability. Regarding extracurricular activities, the majority of girls performed household work (56.4%) and some artistic activity (51.3%) while sporting activities were most common among boys (61%). The results of the Poisson regression model indicated that sleep bruxism was most prevalent in children who scored highly in the Neuroticism sub-scale, and who frequently performed household tasks. Conclusion Children whose personality domain has a high level of Neuroticism and who perform household chores imposed by the family are more vulnerable to sleep bruxism.

Inexistência de diferenças de sexo no fator g (inteligência geral) e nas habilidades específicas em crianças de duas capitais brasileiras

This paper intended to verify sex differences on the g factor (general intelligence) and specific abilities from a sample of children from two Brazilian cities: Belo Horizonte (BH) and Porto Alegre (PA). The sample from BH (n=1.316) aged 5 to 11 years was examined with a battery of intelligence (CPM, Verbal Scale of WISC-III, R-2), psychomotor (Bender) and school achievement tests. The sample from PA (n=779) aged 5 to 11 years was examined with Matrices Progressives Raven. The analysis from these tests shows that the majority of sex differences on specific abilities are not statistically significant. The use of Method Correlated Vectors, which is a most sophisticated method of analyzing general intelligence (g factor), indicates that there are no sex differences. These results support the international records about non-existence of cognitive difference relate to sex in childhood and adolescence.

WISC-III e WAIS-III na avaliação da inteligência de cegos

Owing to the almost lack of a national research on psychological testing for the evaluation of blind people, a psychometric study has been developed with the WISC-III and WAIS-III verbal scales. After adaptations in stimuli and instructions, scales were applied to 120 children and 52 adults in Belo Horizonte MG Brazil. Results show that modified verbal scales had a good internal consistency (? > 0.80) and the factorial analysis clearly indicated the presence of a single principal component. Actually it explains a total of 81% and 64% for WISC III and WAIS III respectively. Since adaptations do not affect the factorial structure of the above-mentioned scales, professionals may use the modified scales to measure the intelligence of blind people.Owing to the almost lack of a national research on psychological testing for the evaluation of blind people, a psychometric study has been developed with the WISC-III and WAIS-III verbal scales. After adaptations in stimuli and instructions, scales were applied to 120 children and 52 adults in Belo Horizonte MG Brazil. Results show that modified verbal scales had a good internal consistency (a > 0.80) and the factorial analysis clearly indicated the presence of a single principal component. Actually it explains a total of 81% and 64% for WISC III and WAIS III respectively. Since adaptations do not affect the factorial structure of the above-mentioned scales, professionals may use the modified scales to measure the intelligence of blind people.

Evidências preliminares da efetividade do treinamento cognitivo para melhorar a inteligência de crianças escolares

The present research intends to verify the effectiveness of a cognitive training (CT) to foster intelligence of school Brazilian children from different intellectual levels. Sixteen fourth-grade boys (M = 8.75 years; SD = .44) took part in this study and were randomly selected to the training group (TG) or control group (CG). In the pre and posttest, all children were assessed using measures with measures of fluid, crystallized intelligence, and school achievement. For the training program we used working memory task for a period of two months. Results: no statically significant difference was found between both groups at posttest in none of the measures used. However, after training, there was a reduction of the differences between GC and GF on measures of fluid intelligence. In the case of Raven, the difference between CG and GE (favorable to GC) dropped from d = .126 to .058. In the TNVRI test, the initial difference in favor of CG (d = .177) became negative (d = -.384), therefore in favor of GE. This small benefit was not observed in tests of school knowledge, where GC had the biggest gains in the post-test assessment. The results are partially supported in the literature. However, studies with a larger sample, more training sessions and longer interval between post-tests to verify the generality of these findings.

Análise de itens do desenho da figura humana: aplicação de TRI

The Human Figure Drawings is one of the most divulged and used instruments in the practice of psychological evaluation of children in Brazil. Recently, Wechsler (2000, 2003) published a new correction system to cognitive evaluation. This work constitutes the first attempt of psychometric analysis of items related to male figure using mathematic models from Item Response Theory (IRT). The analysis of the results obtained in two samples of children (711 from the city of Campo Grande and 564 from the city of Belo Horizonte) with the Male Drawing points that the internal consistency of the instrument is adequate (.87) when 53 items are considered. Nevertheless, the IRT analysis, polytomous item responses, shows problems of difficulty and discrimination of a group of items. Its inferred that the instrument is not well calibrated and consequently there is a necessity of adjustments on the set of items that compound it.