Eight experiments investigated the effects of visual, spatial, auditory, and executive interference on the symbolic comparison of animal size and ferocity, semantic goodness of words, and numbers. Dynamic visual noise (DVN) and the reading of visually presented stimulus items were shown to selectively interfere with response times on the animal…

We examine the visual processing of high-functioning adults with developmental dyslexia (mean Performance IQ=126.5) and current phonological problems. In comparison to an age- and IQ-matched control group, the group with dyslexia showed deficits in two tasks associated with magnocellular/dorsal pathway function. For the "frequency doubling"…

We investigated the role of executive and spatial representational processes in impaired performance of block construction tasks by children with Williams syndrome (WS), a rare genetic defect that results in severely impaired spatial cognition. In Experiment 1, we examined performance in two kinds of block construction tasks, Simple Puzzles, in…

The effects of age, task, and egocentric responding on visual-spatial perspective taking were studied among 41 preschool children between 3.0 and 5.9 years of age. Children were individually administered three perspective-taking measures: the upside-down/right-side-up task, a block task, and a picture box task, all previously described in the…

A dual-processing paradigm was used to investigate information processing limitations underlying specific language impairment (SLI). School-age children with and without SLI were asked to recall verbal and spatial stimuli in situations that varied the number of tasks that were required and the speed at which stimuli were presented. Children…

Multielement visual tracking and visual search are 2 tasks that are held to require visual-spatial attention. The authors used the attentional operating characteristic (AOC) method to determine whether both tasks draw continuously on the same attentional resource (i.e., whether the 2 tasks are mutually exclusive). The authors found that observers…

The cAMP/PKA pathway plays a critical role in learning and memory systems in animals ranging from mice to "Drosophila" to "Aplysia." Studies of olfactory learning in "Drosophila" suggest that altered expression of either positive or negative regulators of the cAMP/PKA signaling pathway beyond a certain optimum range may be deleterious. Here we…

Surface similarity generally promotes reasoning by analogy and physical similarity has been shown to have a powerful positive effect on very young children's use of a scale model as a source of information about another space. The research reported here investigated 2 1/2-year-old children's performance in an object retrieval task when asked to…

The current work examined age differences in the classification of novel object images that vary in continuous dimensions of structural shape. The structural dimensions employed are two that share a privileged status in the visual analysis and representation of objects: the shape of discrete prominent parts and the attachment positions of those…

Eighty blindfolded healthy female subjects participated in an active and a passive straight-ahead pointing task to study the estimation of the subjective sagittal middle in the presence or absence of an active haptic exploration. Subjects were to point straight-ahead with their left or right index finger starting from different right- or…

Single-task and dual-task versions of verbal and spatial serial order memory tasks were administered to 120 students tested for working memory capacity with four previously validated measures. In the dual-task versions, similarity between the memory material and the material of the secondary processing task was varied. With verbal material, three…

Background: The executive functions of inhibition, planning, flexible shifting of actions, and working memory are commonly reported to be impaired in neurodevelopmental disorders. Method: We compared these abilities in children (8?12 years) with high functioning autism (HFA, n = 17), attention deficit-hyperactivity disorder (ADHD, n = 21) and…

Four different age groups (8-9-year-olds, 11-12-year-olds, 13-15-year-olds and young adults) performed a spatial rule-switch task in which the sorting rule had to be detected on the basis of feedback or on the basis of switch cues. Performance errors were examined on the basis of a recently introduced method of error scoring for the Wisconsin Card…

A general framework is outlined for describing the relationship of cognition to brain systems. The model provides for empirical investigations at many levels--computational, chronometric, spatial imaging, and cellular--and argues for the logical interrelationship of these areas of investigation. It is applied to selective visual-spatial attention…

Background: There is growing literature suggesting that some children diagnosed with attention deficit hyperactivity disorder (ADHD) can show a significant bias in attention away from left space. Here we examine mechanisms that may underpin these effects in both clinical and non-clinical child populations. Unilateral spatial inattention…