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Abstract:
Some prosopagnosic patients show evidence of unconscious or
"covert" face recognition, despite poor performance on tests of
overt recognition such as naming faces or judging their
familiarity. This dissociation seems to suggest that visual face
recognition processes are intact in such patients, and merely
disconnected from higher cognitive systems necessary for conscious
awareness. We earlier showed that the dissociation was consistent
with the functioning of a damaged neural network for visual face
recognition, with no separate systems for consciousness
hypothesized. Our model demonstrated savings in face-name
relearning, faster perception of familiar faces, and semantic
priming by unrecognized faces after damage that reduced its overt
face recognition to chance levels. Here we report that the same
model can account for a number of other covert face recognition
findings, including sequential associative priming by faces, forced
choice cued recognition, and provoked overt recognition, as well as
demonstrating impaired overt recognition on a wider array of
measures. We also account for the curious behavior of a patient who
could overtly recognize neither faces nor names, but could judge
which ones went together. We conclude that covert recognition is
most parsimoniously explained as an intermediate level of damage to
the face recognition system, resulting in failure on overt tasks
but still allowing the residual knowledge of the system to be
manifest in some so-called covert tasks.
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