Fragile X syndrome (FXS) is the most common form of heritable mental retardation, affecting (~ around) 1 in 4000 males. The syndrome arises from expansion of a trinucleotide repeat in the 5'-untranslated region of the fragile X mental retardation 1 ("FMR1") gene, leading to methylation of the promoter sequence and lack of the fragile X mental…

The parietal cortex has been proposed as part of the neural network for guiding spatial attention. However, it is unclear to what degree the parietal cortex contributes to the attentional modulations of activities of the visual cortex and the engagement of the frontal cortex in the attention network. We recorded behavioural performance and…

Recently developed accounts of language comprehension propose that sentences are understood by constructing a perceptual simulation of the events being described. These simulations involve the re-activation of patterns of brain activation that were formed during the comprehender's interaction with the world. In two experiments we explored the…

In 3 experiments the authors investigate how errors in perception produce errors in drawings. In Experiment 1, when Shepard stimuli were shown as a pair of tables, participants made severe errors in trying to adjust 1 part of the stimulus to match the other. When the table legs were removed, revealing a pair of parallelograms with minimal…

Many simple experiments can be performed in the classroom to explore the physics of vision. Students can learn of the two types of receptive cells (rods and cones), their distribution on the retina and the existence of the blind spot.

We studied how category typicality and out-of-category relatedness affect speeded category verification (vote ''yes'' if pictured object is clothing) in typically developing 4- to 14-year-olds and adults. Stimuli were typical and atypical category objects (e.g., pants, glove) and related and unrelated out-of-category objects (e.g., necklace,…

Understanding the intentional actions of others is a fundamental part of human social cognition and behavior. An important question is therefore whether other animal species, especially our nearest relatives the chimpanzees, also understand the intentional actions of others. Here we show that chimpanzees spontaneously (without training) behave…

Visual attention is preattentively drawn to abrupt onsets of stimuli appearing in a visual array. In this experiment, I examined the speed of attentional capture for persons with and without mental retardation. Participants identified target stimuli that were signaled by a valid location cue (20% of the time), an invalid location cue (60% of the…

Background: Very little is known about the neuropsychological correlates of adaptive functioning in people with intellectual disabilities (ID). This study examined whether specific cognitive deficits and demographic variables predicted everyday functioning in adults with ID. Method: People with ID (n = 101; ages 19-41 years; mean education = 11…

Few studies have specifically investigated the cognitive correlates of employment for persons with mental retardation. To evaluate the relationship of cognitive and adaptive functioning to work status, 56 competitively employed and 55 unemployed individuals with mental retardation underwent a comprehensive neuropsychological and adaptive…

Ninety university undergraduate students were tested on a number of tasks assessing their recognition of possible and impossible figures, mental rotation, ideational fluency, and self-report artistic and creative characteristics. Scores on the Impossible Figures Task (IFT-14) and the Mental Rotation Test, and self-ratings on the Artistic…

Perceptual grouping by luminance similarity and by proximity was investigated in infants with Williams syndrome (WS) aged between 6 and 36 months (visit 1, N=29). WS infants who were still under 36 months old, 8 months later, repeated the testing procedure (visit 2, N=15). Performance was compared to typically developing (TD) infants aged from 2…

This study assessed the effects of multi-sensory training on the understanding of the alphabetic principle in kindergarten children from low socio-economic status families. Two interventions were compared, called HVAM (visual and haptic exploration of letters) and VAM (visual exploration of letters). The interventions were conducted by either…

Infants represent the acts of others and their own acts in commensurate terms. They can recognize cross-modal equivalences between acts they see others perform and their own felt bodily movements. This recognition of self-other equivalences in action gives rise to interpreting others as having similar psychological states such as perceptions and…

Visual stress--a condition in which unpleasant visual symptoms are experienced when reading--has been reported to be more prevalent in dyslexic individuals but at the present time the relationship between dyslexia and visual stress remains controversial. ViSS, a computerized visual stress screener that incorporates reading-like visual search, has…