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Abstract:
Does attentional bias towards the right visual field (induced
by unilateral neglect) change the holistic strategy normally used
for processing faces? In two experiments we presented chimeric
faces composed either from the left or from the right half of a
face, and their mirror images. Participants matched and identified
the chimeras with the original faces. Control subjects showed a
significant left-field bias in both experiments. In contrast, a
strong right-field bias was found in patients. In a third
experiment, participants associated face parts presented either in
isolation or in face context, with persons the face of whom they
studied before either in normal configuration or scrambled. A
same-different task was used in the fourth experiment. In the
"different" condition, faces differed on global features, on
specific parts, or on a combination of global and part changes.
Controls showed clear preference for holistic processing in both
experiments. Most patients revealed a clear parts-oriented
preference, and some showed a slight preference for holistic
processing or no reliable trends. Moreover, patients performed
similarly with natural and scrambled faces. We suggest that left
hemineglect may involve not only a reversal of the normal
left-field superiority in face processing but also a shift from a
predominantly holistic type of processing to an analytic,
left-hemisphere mode of processing.
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