Concept formation and categorization of complex, asymmetric, and impossible figures.

Impossible figures are striking examples of inconsistencies between global and local perceptual structures, in which the overall spatial configuration of the depicted image does not yield a coherent three-dimensional object. In order to investigate whether structural "impossibility" is an important perceptual property of depicted objects, we used a category formation task in which subjects were asked to divide pictures of shapes into groups that seemed most natural to them. Category formation is usually unidimensional, such that sorting is dominated by a single perceptual property, so this task can serve as a measure of which dimensions are most salient. In Experiment 1, subjects received sets of 12 line drawings consisting of six possible and six impossible objects. Very few subjects grouped the figures by impossibility on the first try, and only half did so after multiple attempts at sorting. In Experiment 2, we investigated other global properties of figures: symmetry and complexity. Subjects readily sorted objects by complexity, but seldom by symmetry. In Experiment 3, subjects were asked to draw each of the figures before sorting them, which had only a minimal effect on categorization. Finally, in Experiment 4, subjects were explicitly instructed to divide the shapes by symmetry or impossibility. Performance on this task was perfect for symmetry, but not for impossibility. Although global properties of figures seem extremely important to our perception, the results suggest that some of these cues are not immediately obvious or salient for most observers.

Effect of a retention interval between pre-exposure and conditioning on latent inhibition in humans using a blink conditioning procedure

El fenómeno de la inhibición latente se refi ere al retraso que se observa cuando se presenta repetidamente sin consecuencias un estímulo que va a ser posteriormente condicionado. En este trabajo empleamos un procedimiento de condicionamiento palpebral para analizar la inhibición latente en participantes humanos. El Experimento 1 reveló que el procedimiento empleado era adecuado para reproducir el efecto de inhibición latente. En el Experimento 2, la introducción de un intervalo de tres minutos entre las fases de preexposición y condicionamiento dio lugar a la atenuación de la inhibición latente. Estos resultados contribuyen a la identifi cación de los mecanismos que participan en la preexposición y posterior condicionamiento de un estímulo, aspectos particularmente importantes si tenemos en cuenta que el fenómeno de la inhibición latente ha sido utilizado repetidamente como un instrumento para analizar el curso del proceso atencional tanto en poblaciones normales como con determinadas psicopatologías(AU)

Latent inhibition, retarded learning after pre-exposure to the to-be-conditioned stimulus, was examined using a blink conditioned procedure in humans. Experiment 1 showed that the procedure is suited to inducing the latent inhibition effect. In Experiment 2, the introduction of a 3-minute interval between pre-exposure and conditioning phases attenuated latent inhibition. These results contribute to identify the mechanisms involved in pre-exposure and subsequent conditioning of a stimulus, which is particularly important if we bear in mind that latent inhibition has been used repeatedly as an instrument to analyze the course of attentional processes in normal and pathological populations(AU)

Effects of memory load on visual search

No está claro el efecto que la carga de memoria tiene sobre la atención en la Búsqueda Visual (BV): se ha encontrado tanto ausencia como efectos negativos y positivos de la carga de memoria en BV. El principal objetivo del presente trabajo fue explorar si la carga de memoria puede modular una tarea de BV por medio de la influencia del «estado o set atencional» de los participantes, generado a través del orden (aleatorio versus bloqueado) y el tiempo (largo versus corto) de presentación de los ensayos. En el experimento 1 se aleatorizó el orden de presentación (5, 10 y 15 estímulos), mientras que para los experimentos 2A y 2B permaneció constante (10 estímulos). En estos últimos cambiamos el tiempo de presentación (3000 versus 1300, respectivamente). Los resultados mostraron ausencia de efectos de la carga de memoria en los experimentos 1 y 2A, mientras que sí se encontraron en el experimento 2B: los TRs en la tarea de BV fueron significativamente mayores con carga alta de memoria; apoyando nuestra hipótesis sobre el «set atencional». Se discuten también otras posibles implicaciones teóricas para comprender mejor cómo la carga de memoria puede modular los procesos atencionales involucrados en BV (AU)

It remains unclear how memory load affects attentional processes in visual search (VS). No effects, as well as beneficial and detrimental effects of memory load, have been found in this type of task. The main goal of the present research was to explore whether memory load has a modulating effect on VS by means of a different attentional set induced by the order of trials (mixed vs. blocked) and by the time presentation of visual display (long vs. short). In Experiment 1, we randomized the order of type of trial (5, 10 and 15 items presented in the display) while it remained constant (10 items) in Experiments 2A and 2B. In the later experiments, we also changed time presentation of visual display (3000 vs. 1300 ms, respectively). Results showed no differential effects of memory load in Experiments 1 and 2A, but they showed up in Experiment 2B: RTs were longer in the attentional task for trials under high memory load conditions. Although our hypothesis of the attentional set is supported by the results, other theoretical implications are also worth discussing in order to better understand how memory load may modulate attentional processes in VS (AU)

Efecto de la apertura del estímulo en la dominancia global en tareas de categorización de la orientación / Effect of stimulus opening size in global dominance with orientation classifi cation task

El objetivo del presente trabajo es averiguar si la dominancia global está en función del grado de apertura del estímulo en tareas de categorización de la orientación y el papel que desempeña la saliencia de la apertura global y su coincidencia con los ejes de simetría verticales del contexto. En el primer experimento se introdujeron estímulos jerárquicos concéntricos abiertos a la derecha o izquierda, en los que los participantes debían indicar la dirección de la apertura. Se incluyeron aperturas del 10, 25 y 50% del contorno total de la circunferencia. Los resultados mostraron ventaja local con estímulos del 10%, ausencia de ventaja global o local con estímulos del 25% y ventaja global con los del 50%. En el segundo experimento se introdujeron estímulos con apertura del 50%, presentados aleatoriamente en diversas posiciones del campo visual con el objetivo de anular la coincidencia de la apertura de la figura global con ejes de simetría vertical del contexto. Los resultados muestran una ausencia de ventaja global. Estos hallazgos muestran que la dominancia global con tareas de categorización de la orientación está en función de características del estímulo, como el grado de apertura, y de estrategias que se utilicen en el reconocimiento visual (AU)

The aims of this study is to examine whether global dominance depends on the opening size of the stimulus with concentric hierarchical figures and orientation classification task and to determine the role of the salience of global opening and its coincidence with vertical symmetry axis of context. In the first experiment, participants had to indicate the opening direction of stimuli, which were open-left and open-right figures. Three openings were included: 10, 25 and 50% of the total circle perimeter. The results showed a local advantage with stimuli of 10%, absence of global or local advantage with stimuli of 25% and global advantage with stimuli of 50%. In the second experiment, stimuli with an opening of 50% were presented randomly in several positions in the visual fi eld in order to avoid the coincidence of global opening with the vertical symmetry axis of context. The results showed an absence of global or local advantage. These findings indicate that global dominance with orientation classification task depends on stimulus characteristics such as opening size, and strategies used in visual recognition (AU)

Effect of initial status and growth in pseudoword reading on Spanish reading comprehension at the end of first grade / Efecto del estado inicial y progreso en lectura de pseudopalabras sobre la comprensión lectora en español al finalizar el primer grado

This study analyzes the effect of initial status and growth in Spanish pseudoword reading in kindergarten and fi rst grade on reading comprehension in Spanish at the end of first grade. One hundred and sixtyeight Spanish-speaking English learners who were learning to read in Spanish and English in the United States participated in the study. Results of hierarchical linear modeling indicate that students grew, on average, by 95 letter-sounds in Spanish from the middle of kindergarten to the end of first grade. Structural equation modeling indicated that 53% of the variance in Spanish reading comprehension at the end of first grade was explained by Spanish initial status on pseudoword reading, Spanish kindergarten overall reading performance, and growth in Spanish pseudoword reading. Findings are important in a Response to Intervention approach where screening and progress monitoring of pseudoword reading helps educators determine the level of support beginning readers need to acquire the alphabetic principle, an important skill that contributes substantially to Spanish reading comprehension(AU)

Este estudio analiza el efecto del estado inicial y progreso en lectura de pseudopalabras en niños españoles de Educación Infantil y primer grado sobre la comprensión lectora al finalizar el primer grado. Ciento sesenta y ocho estudiantes de habla española que estaban aprendiendo a leer en español e inglés en los Estados Unidos participaron en el estudio. Los resultados del modelo jerárquico lineal indican que los estudiantes alcanzaron un promedio de aprendizaje de 95 sonidos de letras en español desde la mitad del jardín de infantes hasta finalizar el primer grado. Modelos de ecuaciones estructurales indicó que al finalizar el primer grado el 53% de la varianza en comprensión lectora de español se explica por el estado inicial de lectura de pseudopalabras, el rendimiento global de lectura en español en el período de Educación Infantil, y el progreso en lectura de pseudopalabras en español. Los hallazgos son importantes y con implicaciones para un modelo de respuesta a la intervención ya que tanto en la detección como en el seguimiento el control de los avances que se producen en la lectura de pseudopalabras ayudaría a los profesores a determinar el nivel de apoyo que necesitan los lectores principiantes para adquirir el principio alfabético, una habilidad importante que contribuye sustancialmente a la comprensión lectora en español (AU)

Use of multilevel logistic regression to identify the causes of differential item functioning / Utilización de la regresión logística multinivel para identificar las causas del funcionamiento diferencial de los ítems

Given that a key function of tests is to serve as evaluation instruments and for decision making in the fields of psychology and education, the possibility that some of their items may show differential behaviour is a major concern for psychometricians. In recent decades, important progress has been made as regards the efficacy of techniques designed to detect this differential item functioning (DIF). However, the findings are scant when it comes to explaining its causes. The present study addresses this problem from the perspective of multilevel analysis. Starting from a case study in the area of transcultural comparisons, multilevel logistic regression is used: 1) to identify the item characteristics associated with the presence of DIF; 2) to estimate the proportion of variation in the DIF coefficients that is explained by these characteristics; and 3) to evaluate alternative explanations of the DIF by comparing the explanatory power or fit of different sequential models. The comparison of these models confirmed one of the two alternatives (familiarity with the stimulus) and rejected the other (the topic area) as being a cause of differential functioning with respect to the compared groups (AU)

Dada la relevancia de los tests como instrumentos de evaluación y de toma de decisiones en los campos de la psicología y de la educación, la posibilidad de que algunos de sus ítems presenten un comportamiento diferencial constituye una preocupación central de los psicómetras. En las últimas décadas se han producido importantes avances con respecto a las técnicas diseñadas para detectar el funcionamiento diferencial de los ítems (DIF). Sin embargo, los hallazgos son escasos en lo que respecta a identificar las causas que lo explican. El presente trabajo aborda este problema desde la perspectiva del análisis multinivel. Partiendo del estudio de un caso del ámbito de las comparaciones transculturales, se utiliza la regresión logística multinivel para: 1) identificar las características de los ítems asociadas a la presencia de DIF; 2) estimar la proporción de la variación en los coeficientes de DIF explicada por tales características; y 3) evaluar explicaciones alternativas para el DIF comparando la capacidad explicativa o el ajuste de diferentes modelos. La comparación entre tales modelos permitió confirmar una de las dos alternativas (la familiaridad con el estímulo) y descartar la otra (el tema de estudio) como causa del funcionamiento diferencial de los ítems en los grupos comparados (AU)

Hand movement deviations in a visual search task with cross modal cuing

The purpose of this study is to demonstrate the cross-modal effects of anauditory organization on a visual search task and to investigate the influenceof the level of detail in instructions describing or hinting at the associationsbetween auditory stimuli and the possible locations of a visual target. Inaddition to measuring the participants’ reaction times, we paid specialattention to tracking the hand movements toward the target. According tothe results, the auditory stimuli unassociated with the target locationsslightly –but significantly- increased the deviation of the hand movementfrom the path leading to the target location. The increase in the deviationdepended on the degree of association between auditory stimuli and targetlocations, albeit not on the level of detail in the instructions about the task(AU)

Stimulus intensity modulates associative and nonassociative responding in preweanling rats.

The purpose of the present study was to determine whether preweanling rats respond differentially to the intensity and energy source of a stimulus. Previous studies have suggested that infants process compound stimuli based on net stimulus intensity regardless of the energy source of the compound's elements, but more direct tests have been needed of the infant's response to the stimulus attributes of intensity and energy source. This response was tested for auditory and visual stimuli that had been equated (Experiment 1) in terms of perceived intensity (low and high). Intensity level and energy source of the stimuli were varied independently within nonassociative (Experiment 2) and associative (Experiment 3) procedures. The overall results indicate that stimuli of a low-perceived intensity were processed in terms of their intensity, whereas high-intensity stimuli were processed on the basis of energy source. These results are relevant to contemporary issues of cognitive development in humans and animals.