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Abstract:
The tendency to categorise unfamiliar stimuli as familiar has
been found to increase as a result of both normal aging and frontal
lobe pathology. This study examined the specificity of this, and
possible causal mechanisms. We found that there is a tendency for
elderly participants to claim that unfamiliar people are famous
(relative to young controls) as it was for our frontal lobe
patient, MR (relative to age-matched controls). This tendency is
found for both faces and peoples names, which suggests that it
cannot be a perceptual phenomenon. However, in both elderly and MR,
false recognition does not extend to vocabulary, place names or
news events suggesting that the category of people is
disproportionately susceptible to effects of false recognition. A
novel experiment was carried out using morphed famous-unfamiliar
faces, on patient MR. The tendency to categorise these stimuli as
familiar was associated with the retrieval of false generic
biographical information, but not specific information (e.g.
names). It is suggested that inappropriate 'background' information
(e.g. prior conversations, and other contextual effects) is
inappropriately bound with the novel stimulus leading to this false
sense of familiarity. This is supported by the results of a final
experiment, which shows that MR falsely recognises different items
on different occasions.
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