Williams syndrome is a rare, genetically-based
disorder resulting in mental retardation and an unusual
pattern of strengths and weaknesses in cognitive abilities.
Relatively preserved language capacities are paired with
profound impairments in spatial ability. Barbara Landau and
I are using eye tracking measures obtained during the
performance of various spatial construction tasks to gain a
detailed understanding of the nature of their spatial
deficit and how it affects spatial language. Our initial
experiments compared normal adults, mental age-matched
controls and children with Williams syndrome on a task
requiring subjects to arrange a set of parts to match a
model. The results were presented at Psychonomics in Dallas
in November of 1998.
The sequence of eye movements during solution of the puzzle
provides information on the order in which information is
acquired and how many "chunks" of spatial information are
picked up in each fixation. On these measures, children
with Williams syndrome and age-matched controls look
similar. However, Williams syndrome children make many more
errors and often have trouble correcting them. You can
appreciate some of these difficulties by watching a
playback of the eye movements and block placement during
puzzle solution. The following demonstration presents a
playback of four trials from the experiment. The first two
are Williams subjects and the last two are mental
age-matched controls. Hint:
You should set your browser for full screen viewing.
Controls on the screen allow you to pause the presentation,
control the speed of the playback, etc.
Click
here for sample playback of eye
movements.