Objective: How does the behavioral expression of autism in fragile X syndrome (FXS + Aut) compare with idiopathic autism (iAut)? Although social impairments and restricted, repetitive behaviors are common to these variants of autism, closer examination of these symptom domains may reveal meaningful similarities and differences. To this end, the…

This study investigated the effects of retention or promotion in 1st grade on growth trajectories in mathematics and reading achievement over the elementary school years (Grades 1-5). From a large multiethnic sample (n = 784) of children who were below the median in literacy at school entrance, 363 children who were either promoted (n = 251) or…

Background: The prevalence of autism spectrum disorder (ASD) symptomatology is comparatively high in Cornelia de Lange syndrome (CdLS). However, the profile and developmental trajectories of these ASD characteristics are potentially different to those observed in individuals with idiopathic ASD. In this study we examine the ASD profile in CdLS in…

Locating a target in a visual search task is facilitated when the target location is repeated on successive trials. Global statistical properties also influence visual search, but have often been confounded with local regularities (i.e., target location repetition). In two experiments, target locations were not repeated for four successive trials,…

This study clarifies the involvement of short- and long-term memory in novel word-form learning, using the Hebb repetition paradigm. In Experiment 1, participants recalled sequences of visually presented syllables (e.g., "la"-"va"-"bu"-"sa"-"fa"-"ra"-"re"-"si"-"di"), with one particular (Hebb) sequence repeated on every third trial. Crucially,…

Objective: To use confirmatory factor analysis to test the construct validity of the proposed "DSM-5" symptom model of autism spectrum disorder (ASD), in comparison to alternative models, including that described in "DSM-IV-TR." Method: Participants were 708 verbal children and young persons (mean age, 9.5 years) with mild to severe autistic…

This study identifies individual, family, and school factors associated with student mobility. Specifically, for Grade 5 students, parents alive and school location were associated with transfer. For students in Grade 7, gender differences, levels of achievement, feelings about school, number of household tasks, distance to school, and parental…

Holding students back when they do not meet a specific attainment level is common practice in a lot of countries. However, this practice is not without controversy and recent studies point at the negative effects of grade retention, especially in the long-term. The majority of these studies focused on grade retention in primary education. In our…

"Repeated reading" is an academic practice that aims to increase oral reading fluency. "Repeated reading" can be used with students who have developed initial word reading skills but demonstrate inadequate reading fluency for their grade level. During "repeated reading," a student sits in a quiet location with a…

A wide body of literature documents the important role that parents play in supporting children's academic success in school (Houtenville & Conway, 2008; Barnard, 2004; Fan & Chen, 2001). Drawing on this literature, national taskforces and federal legislation consistently identify increased parental involvement as a central goal of…

One of the reasons why commercial video games are popular is that they effectively teach players how to play the game--in many cases as the player plays the game itself. This paper focuses on how to effectively integrate teaching "how to play a game" with teaching an "instructional domain" within a game for learning. By analyzing more than 30…

The "illusion of truth" is traditionally described as the increase in perceived validity of statements when they are repeated (Hasher, Goldstein, & Toppino, 1977). However, subsequent work has demonstrated that the effect can arise due to the increased familiarity or fluency afforded by repetition and not necessarily to repetition…

In this article we propose several modeling choices to extend propensity score analysis to clustered data. We describe different possible model specifications for estimation of the propensity score: single-level model, fixed effects model, and two random effects models. We also consider both conditioning within clusters and conditioning across…

Research continues to try and pinpoint the etiological role of particular genes and brain structure in autistic spectrum disorder (ASD), but despite a host of biological, genetic and neuropsychological research, the symptom profile of pervasive developmental disorders (PDDs) are not yet linked to etiological theory. Debate continues around whether…

Memories have qualitative properties (e.g., the different kinds of features or details that can be retrieved) and quantitative properties (e.g., the frequency and/or strength of retrieval). Here we investigated the relative contribution of these two properties to the retrieval monitoring process. Participants studied a list of words, and memory…