Estimation approaches in cognitive diagnosis modeling when attributes are hierarchically structured / Enfoques de estimación en Modelado Diagnóstico Cognitivo cuando los atributos están estructurados jerárquicamente

BACKGROUND: Although research in cognitive psychology suggests refraining from investigating cognitive skills inisolation, many cognitive diagnosis model (CDM) examples do not take hierarchical attribute structures into account. When hierarchical relationships among the attributes are not considered, CDM estimates may be biased. METHOD: The current study, through simulation and real data analyses, examines the impact of different MMLE-EM approaches on the item and person parameter estimates of the G-DINA, DINA and DINO models when attributes have a hierarchical structure. A number of estimation approaches that can result from modifying either the Q-matrix or prior distribution are proposed. Impact of the proposed approaches on item parameter estimation accuracy and attribute classification are investigated. RESULTS: For the G-DINA model estimation, the Q-matrix type (i.e, explicit vs. implicit) has greater impact than structuring the prior distribution. Specifically, explicit Q-matrices result in better item parameter recovery and higher correct classification rates. In contrast, structuring the prior distribution is more influential on item and person parameter estimates for the reduced models. When prior distribution is structured, the Q-matrix type has almost no influence on item and person parameter estimates of the DINA and DINO models. CONCLUSION: We can conclude that the Q-matrix type has a significant impact on CDM estimation, especially when the estimating model is G-DINA

ANTECEDENTES: a pesar de que investigación en psicología cognitiva sugiere abstenerse de investigar rasgos cognitivos de forma aislada, muchos de los ejemplos en Modelado Diagnóstico Cognitivo (MDC) no tienen en cuenta la estructura jerárquica de los atributos implicados. Sin embargo, las estimaciones que se hagan con los MDC pueden estar sesgadas cuando no se consideran estas relaciones jerárquicas. MÉTODO: a través de la simulación y datos reales, el presente estudio estudia el impacto de diferentes enfoques MMLE-EM en los parámetros estimados para los ítems y las personas según los modelos G-DINA, DINA y DINO cuando los atributos tienen una estructura jerárquica. Se proponen una serie de enfoques de estimación que resultan de modificar la Matriz-Q o la distribución previa. Se investiga el impacto de los enfoques propuestos en la precisión en la estimación de los parámetros de los ítems y la clasificación de atributos. RESULTADO: para la estimación del modelo G-DINA, el tipo de Matriz-Q (es decir, explícita vs. implícita) tiene un impacto mayor al de que la distribución previa esté estructurada. Por el contrario, una distribución previa estructurada influye más sobre la estimación de los parámetros de los ítems y las personas en el caso de los modelos reducidos. CONCLUSIÓN: podemos concluir que el tipo de Matriz-Q tiene un impacto significativo en la estimación de MDC, especialmente en el modelo G-DINA

Estimation approaches in cognitive diagnosis modeling when attributes are hierarchically structured.

BACKGROUND: Although research in cognitive psychology suggests refraining from investigating cognitive skills inisolation, many cognitive diagnosis model (CDM) examples do not take hierarchical attribute structures into account. When hierarchical relationships among the attributes are not considered, CDM estimates may be biased. METHOD: The current study, through simulation and real data analyses, examines the impact of different MMLE-EM approaches on the item and person parameter estimates of the G-DINA, DINA and DINO models when attributes have a hierarchical structure. A number of estimation approaches that can result from modifying either the Q-matrix or prior distribution are proposed. Impact of the proposed approaches on item parameter estimation accuracy and attribute classification are investigated. RESULTS: For the G-DINA model estimation, the Q-matrix type (i.e, explicit vs. implicit) has greater impact than structuring the prior distribution. Specifically, explicit Q-matrices result in better item parameter recovery and higher correct classification rates. In contrast, structuring the prior distribution is more influential on item and person parameter estimates for the reduced models. When prior distribution is structured, the Q-matrix type has almost no influence on item and person parameter estimates of the DINA and DINO models. CONCLUSION: We can conclude that the Q-matrix type has a significant impact on CDM estimation, especially when the estimating model is G-DINA.

What happened to cognitive science?

More than a half-century ago, the 'cognitive revolution', with the influential tenet 'cognition is computation', launched the investigation of the mind through a multidisciplinary endeavour called cognitive science. Despite significant diversity of views regarding its definition and intended scope, this new science, explicitly named in the singular, was meant to have a cohesive subject matter, complementary methods and integrated theories. Multiple signs, however, suggest that over time the prospect of an integrated cohesive science has not materialized. Here we investigate the status of the field in a data-informed manner, focusing on four indicators, two bibliometric and two socio-institutional. These indicators consistently show that the devised multi-disciplinary program failed to transition to a mature inter-disciplinary coherent field. Bibliometrically, the field has been largely subsumed by (cognitive) psychology, and educationally, it exhibits a striking lack of curricular consensus, raising questions about the future of the cognitive science enterprise.

¿Cómo afecta la privación de sueño durante una guardia de 24 horas las funciones cognitivas de los residentes de ortopedia y traumatología? / How does sleep deprivation during 24 hours on call duty affect the cognitive performance orthopaedic residents?

Introducción. La falta de sueño suele presentarse regularmente en los residentes de especialidades médicas durante su proceso de formación. El objetivo principal de nuestro estudio fue comparar las funciones cognitivas basales y después de la privación de sueño posguardia en residentes de ortopedia y traumatología. Material y métodos. Se han incluido en el estudio a residentes de ortopedia y traumatología y se evaluaron la atención y funciones cognitivas a través de los siguientes test: Continuous Performance Test (CPT 2), Digit Spam Directo e Inverso (Versión 5), Fluencia Fonológica de 1 letra y Pasat Test. Todas las evaluaciones basales se realizaron después de un periodo de descanso en domicilio de al menos 6 h y las evaluaciones posguardia fueron realizadas en residentes con menos de 3 h de sueño. Resultados. Diecinueve residentes fueron incluidos en el estudio. La edad media de la serie fue de 27 ± 1,89 años y 15 eran de sexo masculino. El promedio de horas de sueño basal fue de 6,5 h (rango 6-8) y posguardia de 1,5 h (rango 0,5-3). En la evaluación de CPT2 se han encontrado diferencias significativas en el número de aciertos (p = 0,007), número de omisiones (p = 0,004) y perseveraciones (p = 0,036) a la consigna planteada. No hemos encontrado diferencias significativas en los otros test. Conclusión. La falta del sueño posterior a una guardia de 24 h de ortopedia y traumatología afecta la atención de los residentes, aumentando el número de errores y omisiones (AU)

Introduction. Sleep deprivation is usually present in residents during their training program. The purpose of our study was to analyze the cognitive performance of a group of orthopaedic residents before and after 24 hours on call duty. Methods. We include orthopaedic residents and their cognitive functions were evaluated by the following tests: Continuous Performance Test (CPT 2), Digit Spam (Versión 5), 1 letter Fonologic Fluence y Pasat Test. All the tests were done after a sleeping period at home of at least 6 hours and after being on call (sleeping less than 3 hours). Results. Nineteen residents were included in the study. The median age was 27 ± 1.89 and 15 were male. The mean hours of sleeping at home was 6.5 (range 6-8) and after on call duty was 1.5 (range 0.5-3). Statistical difference were found in CPT 2 test en terms of correct answers (p=0.007), omissions (p=0.004) and perseverations (p=0.036). No significant differences were found in the other tests. Conclusion. Sleep deprivation after 24 hours on call duty affects cognitive performance of orthopaedic residents, increasing the number of errors and omissions (AU)

Relaciones asimétricas entre atribuciones y afecto en el trabajo / Asymmetric relationships between attributions and affect in the workplace

En la presente investigación se estudia el afecto generado por las valoraciones cognitivas de los trabajadores sobre los eventos laborales. En esta relación se evalúan dos moderadores, la importancia atribuida a los eventos y el estilo explicativo del trabajador. Setenta y tres trabajadores contestaron un cuestionario de estilos explicativos (nivel inter-sujeto) y un cuestionario diario durante 10 días (nivel intra-sujeto) sobre la valoración cognitiva de eventos y el afecto asociado (N = 730 observaciones). Los resultados del análisis multinivel indican que la influencia de los moderadores en la relación valoración cognitiva-afecto es asimétrica para el afecto positivo y negativo. A nivel intra-sujeto hay una moderación de la importancia atribuida a los sucesos laborales en el afecto negativo, pero no en el positivo. En la misma línea, pero con una influencia inter-nivel, el estilo explicativo tiene efecto moderador para el afecto negativo cuando la importancia es atribuida al evento; pero no así para el afecto positivo. Este estudio aporta elementos para el estudio multinivel de terceras variables en la dinámica diaria de la valoración cognitiva de eventos laborales y del afecto (AU)

The present study focuses on the affect generated by cognitive appraisals of work events in workers' daily life. In this relationship, two moderators have been tested, relevance of the event and explanatory style. Seventy-three workers answered an attributional style questionnaire once (between-level data) and also a daily questionnaire (within-level data) about work events and affect for ten days (N = 730 observations).Multilevel analysis results showed that the influence of moderators in the relationship of appraisal-affect is asymmetric for positive and negative affect. At within-level there is a moderation of the importance attributed to the event for negative affect, but not for positive affect. In the same line, but in an inter-level relationship, the explanatory style has a moderator effect for negative affect when the event is appraised as important. Nevertheless, such an influence is not found for positive affect. The study provides new elements for a multilevel study of third variables in the daily dynamics of appraisal and affect (AU)

Test modificado de clasificación de tarjetas de Wisconsin: normalización y estandarización de la prueba en población española / Modified Wisconsin Card Sorting Test: standardization and norms of the test for a population sample in Spain

Introducción. El test modificado de clasificación de tarjetas de Wisconsin (M-WCST) es una versión breve y modificada del WCST que evalúa las funciones ejecutivas y la flexibilidad mental. Presenta algunas diferencias y ventajas respecto a otras versiones del WCST que se han descrito en la bibliografía. Objetivo. Estandarizar y desarrollar datos normativos calibrados demográficamente para el M-WCST en una muestra representativa de la población española. Sujetos y métodos. Como parte del proyecto multicéntrico Normacog, se administró el M-WCST a 700 participantes (rango: 18-90 años). Se analizaron el efecto de la edad, el nivel educativo y el sexo sobre el M-WCST, y se crearon percentiles y puntuaciones escalares calibradas demográficamente para cada puntuación directa. Resultados. Se observó un efecto significativo de la edad y del nivel educativo sobre las variables analizadas del M-WCST (categorías correctas, errores perseverativos y errores totales), pero no un efecto significativo del sexo en ninguna de las variables. La edad y la educación explicaban un 5,0-21,2% de la varianza en el M-WCST y mostraron que, a mayor edad y menor nivel de educación formal, el número de categorías correctas disminuía y se cometían mayor cantidad de errores. Conclusión. El presente estudio aporta por primera vez los baremos normativos del M-WCST para la población española teniendo en cuenta las características sociodemográficas de nuestra sociedad. Se confirma la influencia de la edad y el nivel educativo sobre el rendimiento del M-WCST (AU)

Introduction. The Modified Wisconsin Card Sorting Test (M-WCST) is a shorter, modified version of the WCST that assesses executive functioning and mental flexibility. The M-WCST presents some differences and advantages compared to other versions of the WCST, as previously described in the scientific literature. Aim. To standardize and develop demographically-calibrated norms for the M-WCST in a sample representing of the population of Spain. Subjects and methods. This study is part of the multisite Normacog project. Seven hundred participants from 18 to 90 years old were assessed using the M-WCST. The effects of age, sex, and educational level on M-WCST performance were analyzed, and demographically-calibrated percentiles and scaled scores corresponding to each raw score were created. Results. The effect of age and level of education on the M-WCST variables analyzed (correct categories, perseverative errors and total errors) was statistically significant, whereas sex was not significant. Age and education explained 5.0-21.2% of the variance in M-WCST performance. Older participants with lower level of formal education completed fewer category sorts and made more errors than younger and more educated participants. Conclusion. This study reports the first normative data for the M-WCST in a contemporary Spanish sample, taking sociodemographic characteristics of the population into account. The influence of age and level of education on the M-WCST performance was confirmed (AU)

The representation of women in cognition.

This discussion expresses concerns raised by the representation of women authors in a recent special issue of Cognition dedicated to future trends. Its broader goal is to increase sensitivity to the contributions of female scientists within major journals across psychological science.

Ignoring facial emotion expressions does not eliminate their influence on cooperation decisions / Ignorar las emociones de otros no evita su efecto en nuestras decisiones cooperativas

Whereas the automaticity of emotion processing has been investigated in several cognitive domains, its mandatory influence on cooperative decision-making is still unexplored. We employed an interference-task to evaluate whether explicit instructions to ignore the emotions of others during alleged interpersonal interactions override their behavioral effects. Participants played a Trust Game multiple times with eight cooperative or non-cooperative partners, who displayed facial expressions of happiness or anger. Emotions were non-predictive regarding the partners’ cooperation. In Experiments 1 and 2 participants were explicitly asked to ignore the emotions, and the uncertainty about the partners’ behavior varied. We found an effect of emotional interference; whereas happy partners speeded cooperative decisions, angry ones speeded non-cooperative choices. This was replicated in Experiment 3, where the request of ignoring emotions was removed. Our results show the inevitable influence of the emotional displays of others during cooperation decisions, which fits with theories that contend for a tight link between emotions and social context (AU)

Pese a que la influencia ejercida por el procesamiento de las emociones ha sido estudiada en diferentes dominios cognitivos, el papel de estas durante la toma decisiones en contextos sociales queda aún por explorar. Utilizamos una tarea de interferencia con el fin de estudiar en qué grado es posible evitar la influencia de las emociones de otras personas cuando nos encontramos en interacción con ellas. Los participantes jugaron, en múltiples rondas, al Juego de la Confianza con ocho compañeros que podían ser de tipo cooperativo o no cooperativo, y cuya expresión facial podía ser de felicidad o de enfado. Las emociones de los compañeros de juego no eran predictivas, en ningún caso, de su grado de cooperación. Tanto en el Experimento 1 como en el Experimento 2 los participantes fueron instruidos de manera explícita que debían ignorar las expresiones emocionales de sus compañeros. La validez de la información personal (el grado de cooperación) fue manipulada entre ambos expresultados revelaron un efecto de interferencia emocional; las expresiones de felicidad redujeron el tiempo necesario para tomar la decisión de cooperación, mientras que las expresiones de enfado acortaron las decisiones de no cooperación. Este efecto de interferencia fue replicado en el Experimento 3, en el que la instrucción explícita de ignorar las emociones de los compañeros había sido eliminada.Nuestros resultados muestran que las emociones de otros nos influyen de manera inevitable durante nuestra interacción con ellos. Esta evidencia es coherente con las teorías que defienden la existencia de un estrecho vínculo entre emociones y contexto social (AU)

Intuitive physics of collision effects on simulated spheres iffering in size, velocity, and material

This is an intuitive physics study of collision events. In two experiments the participants were presented with a simulated 3D scene showing one sphere moving horizontally towards another stationary sphere. The moving sphere stopped just before colliding with the stationary one. Participants were asked to rate the positions which both spheres would have reached after a fixed time if the collision had really occurred. The simulated masses of both spheres and the velocity of the moving one were manipulated. Specifically, in Experiment 1 different implied masses were defined by varying only the size of the spheres; in Experiment 2, different implied masses were defined by varying both the size and the apparent texture (material) of the spheres. Functional Measurement was used to compare the physical laws of collision events with cognitive integration rules. Cognitive rules proved to be more similar to physical laws in Experiment 2, i.e., when both spheres size and apparent texture were manipulated. Surprisingly, in both experiments only half the participants took into account the possibility that the moving sphere could have bounced back after the collision. These and other results are important for teaching elementary physics(AU)

Interference in visual perception by verbal and spatial cognitive activity

In two experiments we tested the hypothesis that cognitive processing based on spatial imagery produces more deterioration of visual perception than cognitive processing based on verbal codes. So, we studied the effect on visual perception of two cognitive tasks, one of spatial imagery and the other a verbal task. In the first one, with 30 participants, we analyzed the mental load and ocular behaviors in both cognitive tasks. In the second experiment, with 29 participants, we studied the effect of both tasks on a visual search task, using a dual-task experimental paradigm. The verbal task presented higher mental load than the imagery task when both tasks were carried out with visual search task, and there was more deterioration in stimulus detection with the verbal task. We can conclude that: (1) cognitive tasks produce important deterioration in the capacities of visual search and identification of stimuli; (2) this deterioration has two components: (a) an inefficient search, associated with alterations of the gaze patterns while performing cognitive tasks, and (b) a general interference, nonspecific to spatial codes, in the process of identification of looked-at stimuli; (3) this cognitive interference is related to the mental load or effort required by the cognitive task (AU)

Mediante dos experimentos hemos puesto a prueba la hipótesis de que el procesamiento cognitivo basado en imaginería espacial produce más deterioro en la percepción visual que el procesamiento basado en códigos verbales. Hemos estudiado el efecto de dos tareas cognitivas, una de imaginería espacial y otra verbal, sobre la percepción visual. En el primer experimento, con 30 participantes, analizamos la carga mental y el comportamiento ocular en ambas tareas cognitivas. En el segundo experimento, con 29 participantes, estudiamos el efecto de ambas tareas sobre una tarea de búsqueda visual, usando el paradigma experimental de doble tarea. La tarea verbal presentó mayor carga mental que la de imaginería espacial cuando ambas tareas se realizaron junto con la tarea de búsqueda visual y hubo un mayor deterioro en la detección de estímulos con la tarea verbal. Concluimos que (1) las tareas cognitivas producen un importante deterioro en capacidades de búsqueda visual e identificación de estímulos visuales; (2) este deterioro tiene dos componentes: (a) búsqueda ineficiente, asociada con alteraciones del patrón de mirada mientras se desarrollan tareas cognitivas, y (b) interferencia general, no específica de códigos espaciales, en el proceso de identificación de estímulos mirados; (3) esta interferencia cognitiva está relacionada con la carga mental o esfuerzo requerido por tareas cognitivas (AU)

Validated intraclass correlation statistics to test item performance models.

A new method, with an application program in Matlab code, is proposed for testing item performance models on empirical databases. This method uses data intraclass correlation statistics as expected correlations to which one compares simple functions of correlations between model predictions and observed item performance. The method rests on a data population model whose validity for the considered data is suitably tested and has been verified for three behavioural measure databases. Contrarily to usual model selection criteria, this method provides an effective way of testing under-fitting and over-fitting, answering the usually neglected question "does this model suitably account for these data?"

Relación entre los estereotipos sobre el envejecimiento y el rendimiento en un programa de estimulación cognitiva / Relationship between aging stereotypes and performance in a cognitive stimulation program

Introducción. El objetivo principal de este trabajo fue estudiar la relación entre los estereotipos negativos sobre el envejecimiento y el rendimiento en un programa de estimulación cognitiva en un grupo de personas mayores con deterioro cognitivo leve (n=55). Material y métodos. Se comparó el rendimiento cognitivo y el nivel de asunción de estereotipos negativos sobre la vejez de los participantes antes y después del programa de estimulación cognitiva. Resultados. Por un lado, se observó un incremento significativo del rendimiento en las capacidades de aprendizaje asociativo y recuerdo de información verbal tras el tratamiento, así como una reducción significativa del nivel de estereotipos negativos sobre la vejez. Por otro lado, se observó que en el grupo de personas que mejoró su rendimiento en aprendizaje asociativo los estereotipos negativos eran más frecuentes e igualmente disminuían tras el tratamiento. Conclusiones. Estos resultados reflejan que las personas que mejoran su rendimiento también reducen sus estereotipos. Esta relación resulta novedosa, ya que si bien la relación entre ausencia de estereotipos y mejor rendimiento había sido ya señalada, no se había observado una relación positiva entre el cambio de estereotipos y el rendimiento cognitivo tras una intervención psicológica(AU)

Introduction. The main goal of the current research was to study the relationship between holding negative aging stereotypes and cognitive performance in a cognitive stimulation program in an older adult group (n=55) with Mild Cognitive Impairment. Material and methods. Performance and stereotypes were contrasted before and after the cognitive stimulation program. Results. Firstly, results showed a significant improvement in associative learning and verbal recall, as well as significant stereotypes score reduction after treatment. Secondly, those who improved their associative learning performance had a higher stereotypes score before the program. Even though, this group also reduced their stereotype score. Conclusions. These findings show that people who improve their cognitive performance also reduce their stereotypes score. This relationship is very novel, because although the correlation between absence of stereotype and better cognitive performance has been found in the literature, a positive correlation between stereotype change and cognitive performance after a psychological treatment has not been observed before(AU)

Bayesian hypothesis testing for psychologists: a tutorial on the Savage-Dickey method.

In the field of cognitive psychology, the p-value hypothesis test has established a stranglehold on statistical reporting. This is unfortunate, as the p-value provides at best a rough estimate of the evidence that the data provide for the presence of an experimental effect. An alternative and arguably more appropriate measure of evidence is conveyed by a Bayesian hypothesis test, which prefers the model with the highest average likelihood. One of the main problems with this Bayesian hypothesis test, however, is that it often requires relatively sophisticated numerical methods for its computation. Here we draw attention to the Savage-Dickey density ratio method, a method that can be used to compute the result of a Bayesian hypothesis test for nested models and under certain plausible restrictions on the parameter priors. Practical examples demonstrate the method's validity, generality, and flexibility.

Using nominal data to examine information integration

Functional measurement studies typically collect numerical data in order to study judgment. The new Nanova (Nominal analysis of “variance”) method allows for expansion of the paradigm to include the study of actual or projected behavior. In everyday life, people carry out actions that can be described using verbal labels, which are nominal data. Nanova is similar to analysis of variance in that significance statements assess the effect of experimentally manipulated factors. The way the methodology can extract cognitive strategies from behavioral actions is illustrated by considering a hypothetical burglar who attends to two safety features of the target homes under consideration. A real illustration is also presented, in which respondents reported both fear and projected actions in response to scenarios describing terrorist attacks. The emotional responses, reported as numbers, were analyzed with analysis of variance. The projected actions, reported nominally, were analyzed with the NANOVA computer program (Weiss, 2009). Two factors embedded in the scenarios, government announcement and public reaction, yielded similar effects on both kinds of response. Neither main effect was significant, nor were the anticipated effects of the variables obtained. With both response modes, the factors interacted significantly(AU)

Initial conditions in the averaging cognitive model

The initial state parameters s0 and w0 are intricate issues of the averaging cognitive models in Information Integration Theory. Usually they are defined as a measure of prior information (Anderson, 1981; 1982) but there are no general rules to deal with them. In fact, there is no agreement as to their treatment except in specific situations such as linear models where they can be merged with the arbitrary zero inter-response scale C0. We present some considerations on their meaning and usefulness in the Functional Measurement approach, starting from different points of view. Furthermore, we suggest a method to deal with their complexity both within each single trial of a factorial design, and between the overall trials of an experiment(AU)

Combined effects of mass and velocity on forward displacement and phenomenological ratings: a functional measurement approach to the momentum metaphor

Representational Momentum (RepMo) refers to the phenomenon that the vanishing position of a moving target is perceived as displaced ahead in the direction of movement. Originally taken to reflect a strict internalization of physical momentum, the finding that the target implied mass did not have an effect led to its subsequent reinterpretation as a second-order isomorphism between mental representations and principles of the physical world. However, very few studies have addressed the effects of mass on RepMo, and consistent replications of the null effect are lacking. The extent of motor engagement of the observers in RepMo tasks has, on the other hand, been suggested to determine the occurrence of the phenomenon; however, no systematic investigations were made of the degree to which it might modulate the effect of target mass. In the present work, we use Information Integration Theory to study the joint effects of different motor responses, target velocity and target mass on RepMo, and also of velocity and target mass on rating responses. Outcomes point not only to an effect of mass on RepMo, as to a differential effect of response modality on kinematic (e.g., velocity) and dynamic (e.g., mass) variables. Comparisons of patterns of mislocalisation with phenomenological ratings suggest that simplification of physical principles, rather than strict internalization or isomorphism per se, might underlie RepMo(AU)

(dis)Función ejecutiva en personas mayores con y sin Alzheimer: Actuación estratégica basada en expectativas / Executive (dys)function in aged people with and without Alzheimer: Expectation-based strategic action

La disfunción ejecutiva (dFE) es una alteración mental central en las personas con demencia de Alzheimer (DA). Aquí exploramos su déficit en un aspecto apenas investigado: la actuación estratégica basada en el manejo de expectativas, desarrolladas mediante un uso novedoso de estímulos familiares. Para ello aplicamos a un grupo de adultos jóvenes sanos y a dos de mayores, uno sin y otro con DA, una variante de la tarea Stroop. Según la eficacia con la que procedan a la ejecución estratégica de la tarea, la influencia de esa actuación predominará o no sobre la del procesamiento automático de los nombres, pudiendo generar patrones de resultados cualitativamente diferentes. Encontramos que mientras los jóvenes muestran un patrón Stroop 'inverso' y los mayores con DA el patrón convencional, el comportamiento de los mayores sin DA se sitúa en un punto intermedio. Eso implica que la DA cursa con una pérdida adicional (a la producida por la edad avanzada) de capacidad para la actuación estratégica basada en expectativas (AU)

The executive dysfunction (EdF) is a central mental alteration in people with Alzheimer' dementia (AD). In this work, we explore its deficit in an aspect that has barely been investigated: strategic action based on managing expectations, developed by the novel use of familiar stimuli. For this purpose, we administered a variant of the Stroop test to a group of healthy young adults and to two groups of aged people, one with and one without AD. Depending on the efficacy with which they performed the task strategically, the influence of this action could predominate the automatic processing of names, thus enabling them to generate qualitatively different patterns of results. We found that, where as the young people showed an inverse Stroop pattern, the aged people with AD displayed the conventional pattern, and the behavior of the aged people without AD was at an intermediate point. This implies that AD evolves with additional loss (to that produced by advanced age) of the capacity for expectation-based strategic action (AU)

Children's knowledge of the earth: a new methodological and statistical approach.

In the field of children's knowledge of the earth, much debate has concerned the question of whether children's naive knowledge-that is, their knowledge before they acquire the standard scientific theory-is coherent (i.e., theory-like) or fragmented. We conducted two studies with large samples (N=328 and N=381) using a new paper-and-pencil test, denoted the EARTH (EArth Representation Test for cHildren), to discriminate between these two alternatives. We performed latent class analyses on the responses to the EARTH to test mental models associated with these alternatives. The naive mental models, as formulated by Vosniadou and Brewer, were not supported by the results. The results indicated that children's knowledge of the earth becomes more consistent as children grow older. These findings support the view that children's naive knowledge is fragmented.

Internet cognitive testing of large samples needed in genetic research.

Quantitative and molecular genetic research requires large samples to provide adequate statistical power, but it is expensive to test large samples in person, especially when the participants are widely distributed geographically. Increasing access to inexpensive and fast Internet connections makes it possible to test large samples efficiently and economically online. Reliability and validity of Internet testing for cognitive ability have not been previously reported; these issues are especially pertinent for testing children. We developed Internet versions of reading, language, mathematics and general cognitive ability tests and investigated their reliability and validity for 10- and 12-year-old children. We tested online more than 2500 pairs of 10-year-old twins and compared their scores to similar internet-based measures administered online to a subsample of the children when they were 12 years old (> 759 pairs). Within 3 months of the online testing at 12 years, we administered standard paper and pencil versions of the reading and mathematics tests in person to 30 children (15 pairs of twins). Scores on Internet-based measures at 10 and 12 years correlated .63 on average across the two years, suggesting substantial stability and high reliability. Correlations of about .80 between Internet measures and in-person testing suggest excellent validity. In addition, the comparison of the internet-based measures to ratings from teachers based on criteria from the UK National Curriculum suggests good concurrent validity for these tests. We conclude that Internet testing can be reliable and valid for collecting cognitive test data on large samples even for children as young as 10 years.

Creative or created: using anecdotes to investigate animal cognition.

In non-human animals, creative behaviour occurs spontaneously only at low frequencies, so is typically missed by standardised observational methods. Experimental approaches have tended to rely overly on paradigms from child development or adult human cognition, which may be inappropriate for species that inhabit very different perceptual worlds and possess quite different motor capacities than humans. The analysis of anecdotes offers a solution to this impasse, provided certain conditions are met. To be reliable, anecdotes must be recorded immediately after observation, and only the records of scientists experienced with the species and the individuals concerned should be used. Even then, interpretation of a single record is always ambiguous, and analysis is feasible only when collation of multiple records shows that a behaviour pattern occurs repeatedly under similar circumstances. This approach has been used successfully to study a number of creative capacities of animals: the distribution, nature and neural correlates of deception across the primate order; the occurrence of teaching in animals; and the neural correlates of several aptitudes--in birds, foraging innovation, and in primates, innovation, social learning and tool-use. Drawing on these approaches, we describe the use of this method to investigate a new problem, the cognition of the African elephant, a species whose sheer size and evolutionary distance from humans renders the conventional methods of comparative psychology of little use. The aim is both to chart the creative cognitive capacities of this species, and to devise appropriate experimental methods to confirm and extend previous findings.