Williams syndrome (WS) is a rare genetic syndrome. As with all rare syndromes, obtaining adequately powered sample sizes is a challenge. Here we present legacy data from seven UK labs, enabling the characterisation of cross-sectional and longitudinal developmental trajectories of verbal and non-verbal development in the largest sample of…

The size of an individual's phonological similarity effect for visually presented material is assumed to reflect his or her ability to recode, and by implication rehearse, information in verbal short-term memory. Many studies have shown that under these conditions, the size of this effect interacts with age, tending to be nonsignificant in…

Studies of inner speech use in ASD have produced conflicting results. Lidstone et al., J "Autism Dev Disord" (2009) hypothesised that Cognitive Profile (i.e., "discrepancy" between non-verbal and verbal abilities) is a predictor of inner speech use amongst children with ASD. They suggested other, contradictory results might be explained in terms…

This paper outlines the strengths and weaknesses in both short-term and long-term memory in Down syndrome, and the implications of these patterns for both other aspects of cognitive development and underlying neural pathology. There is clear evidence that Down syndrome is associated with particularly poor verbal short-term memory performance, and…

According to the mental-state reasoning model of suggestibility, 2 components of theory of mind mediate reductions in suggestibility across the preschool years. The authors examined whether theory-of-mind performance may be legitimately separated into 2 components and explored the memory processes underlying the associations between theory of mind…

Individuals with Williams syndrome (WS) display poor visuo-spatial cognition relative to verbal abilities. Furthermore, whilst perceptual abilities are delayed, visuo-spatial construction abilities are comparatively even weaker, and are characterised by a local bias. We investigated whether this differentiation in visuo-spatial abilities can be…

Two studies are presented that adopt a novel approach to determining whether verbal short-term memory performance is causally related to vocabulary acquisition in childhood. This involves examining whether verbal short-term memory measures are more closely related to the absolute level of individuals' vocabulary, or the rate at which vocabulary…

Non-word repetition, in which participants hear and repeat unfamiliar verbal stimuli, is thought to provide a particularly sensitive measure of verbal short-term memory capacity. However, performance on this task can also be constrained by hearing and speech production skills, and by an individuals' linguistic knowledge. This study examined real…

Background: Individuals with Down syndrome consistently perform less well than appropriately matched comparison groups on tests of verbal short-term memory, despite performing relatively well on non-verbal short-term memory tasks. However, it is not clear whether these findings constitute evidence for a selective deficit in verbal short-term…