CHANGE DETECTION AS A TOOL FOR ASSESSING ATTENTIONAL DEPLOYMENT IN ATYPICAL POPULATIONS: THE CASE OF WILLIAMS SYNDROME
When unexpected changes occur in a visual scene, people often fail to notice them. Because change detection depends on attentional mechanisms, people tend to notice changes that are of special significance. People with Williams syndrome (WMS) have an unusually strong interest in other people that is manifest in relatively spared face recognition skills, heightened social attention and hypersociability. We hypothesized that in a change blindness paradigm participants with WMS would be more sensitive to changes in people in social scenes compared to age, IQ and language matched participants with learning or intellectual disabilities. Two videos were presented, one showing an unexpected change to the identity of an actor and one with numerous unexpected changes during a conversation scene. Subjects in both the WMS and the learning disabilities groups noticed fewer overall changes than age-matched normal controls, suggesting that change detection is especially challenging to people with intellectual disabilities. Consistent with our hypothesis, WMS subjects noticed more person-related changes in the complex scene than did subjects with other intellectual/learning disabilities. WMS subjects attend to social elements of dynamic scenes, decreasing change blindness for changes associated with people.
KEYWORDS: Williams syndrome, change detection, change blindness, attentional biases.