The social and motor context in which restricted and repetitive behaviors (RRBs) occur in autism and their relationship to social traits are not well-understood. Participants with and without autism completed tasks that varied in social and motor engagement and RRB frequency was measured. Motor and verbal RRBs were most common, RRBs varied based…

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…

We investigate the function bias--generalising words to objects with the same function--in typically developing (TD) children, children with autism spectrum disorder (ASD) and children with other developmental disorders. Across four trials, a novel object was named and its function was described and demonstrated. Children then selected the other…

The current study examined delays in syntax and morphology, and vocabulary, in autism spectrum disorder (ASD). Children ages 4-6 years with ASD (n = 21) and typical development (n = 21), matched on nonverbal mental age, completed five language tasks. The ASD group had significant delays in both syntax and morphology, and vocabulary measures, with…

Individuals with an autism spectrum disorder (ASD) are thought to encounter planning difficulties, but experimental research regarding the mastery of planning in ASD is inconsistent. By means of a meta-analysis of 50 planning studies with a combined sample size of 1755 individuals with and 1642 without ASD, we aim to determine whether planning…

Here we examine imaginative drawing abilities in children with Autism Spectrum Disorder (ASD) and learning disabilities (LD) under several conditions: spontaneous production, with use of a template, and combining two real entities to form an "unreal" entity. Sixteen children in each group, matched on mental and chronological age, were…

Working memory (WM) impairments might amplify behavioural difference in genetic syndromes. Murine models of Rubinstein-Taybi syndrome (RTS) evidence memory impairments but there is limited research on memory in RTS. Individuals with RTS and typically developing children completed WM tasks, with participants with RTS completing an IQ assessment and…

Stimulus overselectivity is widely accepted as a stimulus control abnormality in autism spectrum disorders and subsets of other populations. Previous research has demonstrated a link between both chronological and mental age and overselectivity in typical development. However, the age at which children are developmentally ready to respond to…

Although reading skills are critical for the success of individuals with intellectual disabilities, literacy has received little attention in fragile X syndrome (FXS). This study examined the literacy profile of FXS. Boys with FXS (n = 51; mean age 10.2 years) and mental age-matched boys with typical development (n = 35) participated in…

Cognitive flexibility has been measured with inductive reasoning or explicit rule tasks in individuals with autism spectrum disorders (ASD). The "Flexible Item Selection Task" (FIST) differs from previous cognitive flexibility tasks in ASD research by giving children an abstract, ambiguous rule to switch. The ASD group (N = 22; Mean age = 8.28…

The present study explored the relations among lie-telling ability, false belief understanding, and verbal mental age. We found that children with autism spectrum disorder (ASD), like typically developing children, can and do tell antisocial lies (to conceal a transgression) and white lies (in politeness settings). However, children with ASD were…

Aberrant attention is a core feature of fragile X syndrome (FXS), however, little is known regarding the developmental trajectory and underlying physiological processes of attention deficits in FXS. Atypical visual attention is an early emerging and robust indicator of autism in idiopathic (non-FXS) autism. Using a biobehavioral approach with gaze…

Language profiles of children with autistic disorder and intellectual disability (n = 36) were significantly different from the comparison groups of children with intellectual disability (n = 26) and typically developing children (n = 34). The group low-functioning children with autistic disorder obtained a higher mean score on expressive than on…

We observed infant siblings of children with autism later diagnosed with ASD (ASD siblings; n = 17), infant siblings of children with autism with and without other delays (Other Delays and No Delays siblings; n = 12 and n = 19, respectively) and typically developing controls (TD controls; n = 19) during a free-play task at 18 months of age.…

Research on theory of mind (TOM) has provided a major contribution to the understanding of developmental disorders characterized by atypical social behaviour. Yet, there is still little consensus relative to TOM abilities in Williams syndrome (WS). This study used visual and verbal tasks to investigate attribution of intentions in individuals with…