Purpose: The aim of this study was to explore relations between speech sound disorder severity and selective mutism in a group of children with 7q11.23 duplication syndrome (Dup7), a genetic condition predisposing children to childhood apraxia of speech (CAS) and other speech sound disorders and to anxiety disorders, including selective mutism and…

This study investigated the systematic rise in cognitive ability scores over generations, known as the "Flynn Effect," across middle childhood and early adolescence (7-15 years; 291 monozygotic pairs, 298 dizygotic pairs; 89% White). Leveraging the unique structure of the Louisville Twin Study (longitudinal data collected continuously…

Purpose: The current study addresses a gap in the literature regarding syntactic development of adolescent boys with fragile X syndrome (FXS) and Down syndrome (DS). Specifically, we ask whether syntactic skills plateau or continue to change during adolescence for these groups and whether the profile of syntactic change differs between boys with…

Background: Sensory processing differences are reported both in children with ADHD and in children with autism. Given the substantial overlap between autism and ADHD, the current study examined which sensory features were uniquely predictive of autistic traits after controlling for ADHD symptoms, age, IQ, and sex in a sample of children and…

Phenotypical heterogeneity in language abilities is a hallmark of autism but remains poorly understood. The present study collected naturalistic language samples from parent-child interactions. We quantified verbal abilities (mean length of utterance, tokens, types) of 50 Chinese-speaking children (M = 5; 6) and stratified subgroups based on their…

In this article, it is argued that it makes sense to define and distinguish three levels of human intelligence: intelligence as genotypical potential, intelligence as actualised in environmental interaction, and intelligence as measured by tests (IQ). This raises the questions of what is meant by the term "intelligence as potential", and…

This article provides an assessment of French media coverage of intelligence research. The analysis is based on articles published between 1992 and 2020 in French nationwide newspapers, local newspapers and science magazines. Two themes regularly appear in nationwide newspapers and science magazines: environmental effects on IQ and animal…

With just one exception, all of the volumes in Terman's Genetic Studies of Genius report the results of a longitudinal study of more than a thousand intellectually gifted children. That single exception is Volume II, Cox's single-authored "The Early Mental Traits of Three Hundred Geniuses," which instead was a retrospective study of 301…

To characterize autism spectrum-related symptomatology in children with Williams syndrome (WS) with phrase speech or fluent language, the Autism Diagnostic Observation Schedule Module 2 or 3 was administered. The cutoff for autism spectrum was met by 35% (14/40) who completed Module 2 and 30% (18/60) who completed Module 3. Similarities and…

Literature on the level of adaptive functioning and relative strengths and weaknesses in functioning of individuals with Williams syndrome (WS) was reviewed. The electronic databases PsycINFO, PubMed, Expanded Academic, Web of Science, Scopus and ProQuest were searched electronically for relevant articles and dissertations using the search terms…

Each year, the Interagency Autism Coordinating Committee (IACC) releases its annual list of scientific advances that represent significant progress in the field. The 20 studies selected have given new insight into the underlying biology of autism spectrum disorder (ASD) and potential risk factors, examined the state of the science in early…

We describe the performance of 292 4- to 17-year-olds with Williams syndrome (WS) on the Kaufman Brief Intelligence Test-2 (KBIT-2; Kaufman & Kaufman, 2004). Mean IQ Composite, Verbal standard score (SS), and Nonverbal SS were in the borderline range relative to the general population, with variability similar to the general population.…

Background: People with Prader-Willi syndrome (PWS) typically have mild to moderate intellectual deficits, compulsivity, hyperphagia, obesity, and growth hormone deficiencies. Growth hormone treatment (GHT) in PWS has well-established salutatory effects on linear growth and body composition, yet cognitive benefits of GHT, seen in other patient…

Purpose: This study examined use of a speaker's direction of gaze during word learning by boys with fragile X syndrome (FXS), boys with nonsyndromic autism spectrum disorder (ASD), and typically developing (TD) boys. Method: A fast-mapping task with follow-in and discrepant labeling conditions was administered. We expected that the use of speaker…

Neurofibromatosis Type 1 (NF1) is a common autosomal dominant single-gene disorder, in which the co-occurrence of autism spectrum disorder (ASD) has attracted considerable research interest recently with prevalence estimates of 21-40%. However, detailed characterization of the ASD behavioral phenotype in NF1 is still lacking. This study…