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Abstract:
The mere exposure effect (MEE) refers to the observation that
the mere repeated exposure to an unfamiliar stimulus is sufficient
to enhance preference toward it. We investigated the MEE and the
explicit memory in Alzheimers disease (AD) patients and elderly
controls with unfamiliar faces. During the exposure phase, the
subjects estimated the age of faces flashed very briefly on a
computer screen. The MEE was later examined by presenting pairs of
faces (old and new) and asking participants to select the face they
liked best (forced-choice preference task). The participants were
then presented with a forced-choice explicit recognition task.
Normal controls exhibited above-chance preference and recognition
scores for previously exposed faces. The AD patients showed also
the MEE but no explicit recognition. These results suggest that the
processes subtending the MEE are preserved in AD patients despite
their impaired explicit recognition. Given the extremely brief
presentation times and the absence of explicit retrieval, it seems
that the mere exposure effect in AD patients is largely independent
from the depth of perceptual encoding or explicit memory. Our
findings are consistent with Seamon et al.s theoretical proposal
(Journal of Experimental Psychology : Learning, Memory, &
Cognition, 21, 1995) that processes involved in the MEE are
equivalent to those subtending perceptual priming, which seems
relatively preserved in AD patients.
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