A visual conflict hypothesis for global-local visual deficits in Williams Syndrome: simulations and data

Individuals with Williams Syndrome demonstrate impairments in visuospatial cognition. This has been ascribed to a local processing bias. More specifically, it has been proposed that the deficit arises from a problem in disengaging attention from local features. We present preliminary data from an integrated empirical and computational exploration of this phenomenon. Using a connectionist model, we first clarify and formalize the proposal that visuospatial deficits arise from an inability to locally disengage. We then introduce two empirical studies using Navon-style stimuli. The first explored sensitivity to local vs. global features in a perception task, evaluating the effect of a manipulation that raised the salience of global organization. Thirteen children with WS exhibited the same sensitivity to this manipulation as CA-matched controls, suggesting no local bias in perception. The second study focused on image reproduction and demonstrated that in contrast to controls, the children with WS were distracted in their drawings by having the target in front of them rather than drawing from memory. We discuss the results in terms of an inability to disengage during the planning stage of reproduction due to over-focusing on local elements of the current visual stimulus

The development of visuo-spatial processing in children with autism, Down syndrome and Williams syndrome

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Development of metaphor and metonymy comprehension: Receptive vocabulary and conceptual knowledge

Figurative language, such as metaphor and metonymy are common in our daily communication. This is one of the first studies to investigate metaphor and metonymy comprehension using a developmental approach. Forty-five typically developing individuals participated in a metaphor-metonymy verbal comprehension task incorporating 20 short picture-stories. Cross-sectional trajectory analyses linking task performance to either chronological age or receptive vocabulary (mental age, MA) were used to compare the development of metaphor and metonymy. Results showed that development of metaphor and metonymy comprehension is strongly linked with chronological and MA, but metaphor comprehension develops at a slower rate compared to metonymy. It was also found that participants, across all ages, consistently showed around 21% better performance on metonymy. The relationship between metaphor and metonymy comprehension is discussed in terms of linguistic and cognitive models of figurative language comprehension arguing that metonymy is cognitively more basic than metaphor

The atypical development of metaphor and metonymy comprehension in children with autism

One of the most noticeable problems in autism involves the social use of language such as metaphor and metonymy, both of which are very common in daily language use. The present study is the first to investigate the development of metaphor and metonymy comprehension in autism. Eleven children with autism were compared to 17 typically developing children in a metaphor-metonymy comprehension task. Cross-sectional trajectory analyses were used to compare the development of metaphor and metonymy comprehension using a child-friendly story picture task. Trajectories were constructed linking task performance either to chronological age or to measures of mental age. Children with autism showed an impaired metaphor comprehension in relation to both chronological and mental age, whereas performance on metonymy was delayed and in line with their receptive vocabulary. Our results suggest that understanding of metaphors and metonyms are severely affected at all ages examined in the current study

Item and error analysis on Raven's Coloured Progressive Matrices in Williams Syndrome

Raven’s Coloured Progressive Matrices (RCPM) is a standardised test that is commonly used to obtain a non-verbal reasoning score for children. As the RCPM involves the matching of a target to a pattern it is also considered to be a visuo-spatial perception task.RCPM is therefore frequently used in studies in Williams Syndrome (WS), in order tomatch WS participants to a control group or as a single measure to predict performance on a test-condition in developmental trajectory analyses. However, little is known about the performance of participants with WS on the RCPM. The current study compared the type of errors and the difficulty of each item for 53 participants with WS to 53 typically developing children who were individually matched on the total raw score for RCPM. Results showed that the participants with WS made the same proportion of error types and that the proportion of error types changed similarly to those of typically developing controls over development. Furthermore, the differential item difficulty between the two groups was highly similar. It is therefore argued that, although participants with WS are delayed on RCPM, their performance is not atypical which suggests that RCPM performance is supported by typical mechanisms. The RCPM is therefore a useful tool to match WS to control groups or to construct developmental trajectories