| Summary: | Drawing in William syndrome (WS), a rare genetic disorder, is often characterised by production of poorly integrated drawings that focus on the detail of a figure but fail to capture the global configuration. Little research has sought to understand drawing behaviour in WS despite frequent use of drawing as evidence of a local processing bias. This thesis examines factors that influence drawing in WS and typically developing (TD) groups to better characterise drawing performance in WS. In contrast to previous literature, this thesis demonstrates that drawing ability in WS cannot be typified by a bias towards local elements of a figure. Drawing in WS and TD groups was largely comparable, including for local elements. Instead, it is argued that drawing in WS represents reduced strategy-use, associated with two central components of drawing that are unrelated to motor or planning ability. First, individuals with WS demonstrate a failure to represent multiple spatial relations. This is clear from a greater sensitivity to complexity of ' the figure to-be-copied. Complexity in term of the number and type of lines reduced the frequency of strategy use when drawing in WS. Second, individuals with WS show poor attention to a model when copying. This is evidenced by reduced looks to a model in the WS group when drawing, relative to the TD group. Facilitation of drawing to increase the frequency in which drawing strategies are employed improved performance in the WS group to the level of TD individuals. It is argued that the benefit of facilitation is likely to depend on both an improvement in the representation of multiple spatial relations and on increased attention to the model. As a result of an understanding of the factors affecting drawing in both groups and the shortcomings of existing models, a new model of drawing is proposed.
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