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Abstract:
Using a systematic pairing of imagery and perception tasks,
we studied face imagery and face perception in a prosopagnosic
patient, MJH, for both single facial features (Ronald Reagan:
Pointy nose?; Anger: Squinty eyes?) and global faces (Which
celebrity's face is least like the other two?). Results
(consistency of MJH's judgments with those of control subjects)
showed a dissociation between preserved imagery and impaired
perception not just when configural processing of faces was
required but also when feature-based processing of faces was
engaged. Results suggest that, in this individual, when faces are
perceived, deficient configural processing interferes with
preserved feature-based processing. They suggest a general
impairment of all bottom-up (as opposed to top-down) processes,
which supports the view that although sharing representations,
imagery and perception rely on independent functional
mechanisms.
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