The ability to describe routes was assessed in participants with intellectual disability (ID) and participants without ID matched on chronological age (CA) or on mental age (MA). In two experiments, participants learned a route through a virtual environment until they reached a learning criterion. They were then asked to externalize their spatial…

It has been reported that approximate number sense (ANS) task performance is impaired in individuals with Williams syndrome (WS) and Down syndrome (DS). Research with infants has suggested this impairment is caused by sticky fixation in WS and sustained attention deficits for those with DS. This study examined looking patterns of older children…

Sensory symptoms are prevalent in autism spectrum disorder but little is known about the early developmental patterns of these symptoms. This study examined the development of sensory symptoms and the relationship between sensory symptoms and adaptive functioning during early childhood. Three groups of children were followed across three time…

The ability to flexibly adapt to the changing demands of the environment is often reported as a core deficit in fragile X syndrome (FXS). However, the cognitive processes that determine this attentional set-shifting deficit remain elusive. The present study investigated attentional set-shifting ability in fragile X syndrome males with the…

Individuals with Williams syndrome display indiscriminate approach towards strangers. Neuroimaging studies conducted so far have linked this social profile to structural and/or functional abnormalities in WS amygdala and prefrontal cortex. In this study, the neuropsychological hypotheses of amygdala and prefrontal cortex involvement in WS…

Background: In recent years, there has been increased research interest in the functioning of working memory in people with intellectual disabilities. Although studies have repeatedly found these individuals to have weak working memory skills, few investigations have distinguished between different degrees of intellectual disability. This study…

We examined recalled narratives of boys with fragile X syndrome with autism spectrum disorder (FXS-ASD; N = 28) and without ASD (FXS-O; N = 29), and compared them to those of boys with Down syndrome (N = 33) and typically developing (TD) boys (N = 39). Narratives were scored for mentions of macrostructural story grammar elements (introduction,…

We report a cross-syndrome comparison of the development of holistic processing in face recognition in school-aged children with developmental disorders: autism, Down syndrome, and Williams syndrome. The autism group was split into two groups: one with high-functioning children and one with low-functioning children. The latter group has rarely…

This study examined Theory of Mind in Williams syndrome (WS) and in normal chronological age-matched and mental age-matched control groups, using a picture sequencing task. This task assesses understanding of pretence, intention and false belief, while controlling for social-script knowledge and physical cause-and-effect reasoning. The task was…

Background: In the last few years, experimental data have been reported on differences in implicit memory processes of genetically distinct groups of individuals with Intellectual Disability (ID). These evidences are relevant for the more general debate on supposed asynchrony of cognitive maturation in children with abnormal brain development.…

In this paper, we summarize some of our findings from a series of three meta-analyses and discuss their implications for autism research. In the first meta-analysis, we examined studies addressing the theory of mind hypothesis in autism. This analysis revealed that theory of mind disabilities are not unique to autism, although what may be unique…

Background: There are two accounts of categorization performance in autism: that there is an impairment in prototype formation (Klinger & Dawson, 2001) and that there is an impairment in processing features held in common between stimuli (Plaisted, O'Riordan, & Baron-Cohen, 1998). These accounts, together with central coherence theory (Frith,…

Background: Several theorists maintain that exact number abilities rely on language-relevant processes whereas approximate number calls on visuo-spatial skills. We chose two genetic disorders, Williams syndrome and Down's syndrome, which differ in their relative abilities in verbal versus spatial skills, to examine this hypothesis. Five…

Thirty children (under 24 months of age) referred to an early intervention program were administered 3 developmental assessments. Although the Griffiths' Mental Development Scales correlated well with the Bayley Scales of Infant Development and the Battelle Developmental Inventory, the Griffiths' age equivalents were considerably higher than the…