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Abstract:
It has been proposed that both left and right hemispheres are
capable of processing lexical-semantic information, but that only
the left hemisphere can process syntactic information. The present
study tested whether the right hemisphere (RH) differs from the
left hemisphere (LH) in the use of syntactic information to select
the contextually appropriate meaning of ambiguous words such as
"bark". ERPs were recorded from 24 subjects while they read
sentences in four context conditions, followed by the same target
word. Target words were presented either to the left or the right
visual half field (VHF). Sentence contexts were semantically
neutral but syntactically constraining. (Note: Target words are in
capitals: Concordant/Concordant Control: The blind man ran his
hands across the bark/silk TREE; Discordant/Discordant Control:
Without apparent reason they started to bark/shiver TREE.) The
selectional status of the ambiguous words was inferred from the
ERPs to sentence final and target words. Target words were
presented with ISI's of 150 or 1150 ms in two versions of the
experiment. In the short ISI version, results showed that
contextually appropriate and contextually inappropriate meanings
were activated for both VHF presentations. In contrast, in the long
ISI version, contextual selection was found for right but not left
VHF. This pattern of results is consistent with the idea that the
RH cannot use syntactic information to guide meaning
selection.
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