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Abstract:
Using event-related functional magnetic resonance imaging, we
investigated mechanisms underlying ambiguity resolution of
homographs. Theory suggests the correct meaning is obtained by
first retrieving multiple meanings of the word and then
suppressing, or mentally dampening, irrelevant meanings. Subjects
read sentences that ended in homographs. Following a short (100 ms)
or long (3100 ms) delay, a test word was presented. Subjects
indicated if the test word was related to the meaning of the
sentence. Of interest to this study are trials for which test words
were unrelated to the sentence, but were related to the irrelevant
meaning of the homograph (e.g., correctly rejecting the test word
"ace" after reading the sentence "He dug with the spade" versus "He
dug with the shovel"). Behaviorally, interference is observed at
short durations when the test word is related to the irrelevant
meaning of the homograph compared to when the test word is
unrelated to the homograph. With longer test durations, this
interference dissipates. Event-related responses in the fmri signal
patterned after the behavioral data (reaction times and accuracy),
showing differences in response to test words that were related to
the inappropriate meanings of the homographs compared with test
words unrelated to the homographs and differences at the short
delay versus the long delay.
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