Electrophysiological Investigation on the Time-course of Japanese Word Processing.
Okano, Kana.
2012
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Abstract: The aim of the current set of experiments was to understand the
time-course of Japanese word processing. While numerous studies have looked at the
time-course of word processing in Roman alphabetic languages, it is unclear whether the
same processes apply to scripts that are completely dissimilar to the Roman alphabet. In
the first two experiments, we examined within- (Experiment 1) ... read moreand between-script
(Experiment 2) masked repetition priming effects in two Japanese syllabaries - Hiragana and
Katakana. In both experiments native Japanese speakers were presented with repeated or
unrelated pairs of words in the same script (Experiment 1) and different script (Experiment
2). In both experiments there was a significant N250 and N400 priming effect, but the
N/P150 effect was only present in the within-script condition. N250 and N400 effects
appeared later compared to prior work in alphabetic scripts, which suggests that syllabary
scripts place more emphasis on phonological processing compared to languages that use
alphabetic scripts. Experiment 3 investigated this possibility by conducting a masked
cross-modal experiment. Using the same stimuli words as those used in the first two
experiments, we exchanged the target stimuli to auditory words. Once again, we found robust
priming effects on the N400 for both Hiragana and Katakana. Interestingly, however, we also
found a priming effect on the P2 appearing only for Katakana but not Hiragana. We conclude
that Katakana has closer connections with phonology, thus showing a strong mapping of
phonological units onto phonological words during the early stages of word processing.
Hiragana on the other hand seemed to influence priming predominantly through whole-word
representations. Given these results, we proposed a modification of the bimodal
interactive-activation model (BIAM) is to account for word recognition in syllabary
scripts. Experiments 4 and 5 focused on the processing of Japanese logograph (Kanji). In
Experiment 4, we examined whether complex Kanji were decomposed into their constituent
morpho-orthographic units (radicals) during processing similar to morphologically complex
words in alphabetic languages. We achieved this by conducting an ERP masked repetition
priming in prime-target pairs with semantically and orthographically transparent
relationship, semantically opaque but orthographically transparent relationship, and
semantically unrelated but orthographically transparent relationship. We found that
semantically and orthographically transparent pairs were decomposed into its constituent
radicals during processing similar to morphologically complex words, as reflected in
priming effects in the N250 and N400 components. The other two conditions showed marginal
priming effects in the N250, indicating a possibility of morpho-orthographic decomposition,
however, the effects failed to reach significance. The semantically opaque but
orthographically transparent pairs also failed to show priming effects on the N400,
indicating a possibility of interference effects. On the other hand, we did see an N400
effect in the semantically unrelated but orthographically transparent pairs. However, this
appeared to be anteriorly distributed, similar to those seen in object priming. Experiment
5 examined the effects of radical position and function on Kanji decomposition that was not
covered in Experiment 4. This experiment used a lexical decision task and ERPs to examine
the differences in processing of complex Kanji by breaking down the functional (semantic
vs. non-semantic, free- vs. bound radical) and positional (left/right orientation,
top/bottom orientation) information embedded in each radical. We found that in the early
processes of Kanji processing, Kanji orientation and semantic radicals modulated the N250
component especially in Non-words, providing evidence that Kanji readers may be conducting
a first scan of positional and semantic radical information. Non-semantic radicals
modulated the later N400 component, again in Non-words than Words, and more so if
characters contained free-semantic radicals rather than bound-semantic radicals. This
indicated that non-semantic radicals are processed only after semantic radicals are
activated, and more so if semantic radicals could only be processed when attached to a
non-semantic unit. Overall, our results revealed that Japanese word processing can be
understood using the same model of word processing as those used in Roman alphabets. While
there are distinct differences in processing between Japanese and alphabetic scripts due to
fundamental differences in form and function, the underlying processes seem to be
similar.
Thesis (Ph.D.)--Tufts University, 2012.
Submitted to the Dept. of Psychology.
Advisor: Phillip Holcomb.
Committee: Jonathan Grainger, Gina Kuperberg, Joanna Morris, and Katherine Midgley.
Keywords: Cognitive psychology, and Neurosciences.read less - ID:
- 3j333d33g
- Component ID:
- tufts:20955
- To Cite:
- TARC Citation Guide EndNote
