Background:
Williams syndrome (WS) is a rare genetic disorder associated with intellectual impairment, good verbal skills and an unusual social personality. Despite extensive interest in the area, it remains unclear whether theory of mind (ToM) abilities are impaired or intact in WS. This uncertainty most likely relates to the wide range of measures used to assess ToM abilities and the unique profile of strengths and weaknesses associated with the syndrome. The aim of this study was to examine ToM in WS using a nonverbal picture sequencing task. The picture sequencing task was selected so that the WS individuals could not rely on their good verbal skills when performing the task. The paper also aimed to further explore heterogeneity within WS and the possibility of WS subtypes.
Methods:
Langdon et al.'s (1997) picture sequencing task was administered to 30 individuals with WS and to normal chronological-age-matched and mental-age-matched controls. The picture sequencing task assesses understanding of pretence, intention and false belief, while controlling for social script knowledge and physical cause-and-effect reasoning.
Results:
Results indicated a specific deficit in understanding of false belief within the WS group. There was also evidence of heterogeneity in the WS group, with the false belief impairment restricted to only a particular subgroup of WS individuals identified originally by Porter and Coltheart (2005).
Conclusions:
Our research, using a nonverbal task to assess ToM, indicates impaired false belief understanding in a select group of WS individuals. There are some indications that the deficits in social understanding in this group go beyond an impaired ToM.
