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Abstract:
The event-related potential (ERP) repetition effect is
characterized by a late more positive-going wave to repeated
relative to first presentation stimuli. It can be elicited by words
or pictures independently of a response requirement. Investigating
ERP repetition effects in cross-form tasks can shed light on issues
concerning common or dual-code models of representation during
memory processing. Seventeen subjects were presented with 600
stimuli (pictures or names of objects, 800 ms each) on a computer
monitor and instructed to press a button when the real object was
larger than the monitor. 80 of the stimuli were targets (40 words,
40 pictures). Additionally, there were 50 word-word, 50
picture-picture, 50 word-picture and 50 picture-word repetitions
(inter-item lag 1) as well as 120 filler stimuli in quasi-random
order. No target stimuli were repeated. EEG averages were formed
off-line for the different repetition conditions. ERP repetition
effects were statistically reliable for the word-word,
picture-picture and word-picture conditions, but not for the
picture-word repetition condition and larger at posterior than
anterior sites. These findings are more consistent with dual-code
than common-code models of representation. The picture-word
condition appears to mainly involve perceptual processing of the
initially presented picture with relatively little semantic
processing. Therefore the subsequently presented object name does
not elicit a reliable repetition effect. The word-picture condition
requires the mapping of semantic information (the word) onto a
perceptual representation in order to permit a size judgement. This
perceptual representation can then support an ERP repetition effect
to the second, perceptual stimulus.
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