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Rendaku (Japanese sequential voicing) as rule application: an ERP study Yuki Kobayashia, Yoko Sugiokac and Takane Itoa,b Japanese sequential voicing (rendaku) is a process of voicing the initial obstruent of the second member of a compound word in Japanese (e.g. hon ‘book’ + tana ‘shelf’→hon-dana). We conducted an event-related potential measurement experiment to investigate whether rendaku is a regular process of rule application or an analogical process based on lexical memory. When rendaku was applied wrongly to words lexically specified to resist rendaku, a left anterior negativity component, followed by a P600 was observed, whereas applying rendaku against a phonological constraint known as Lyman’s law elicited a P600 component alone. Failure of rendaku application where it should apply yielded an N400. These results suggest that rendaku is a process involving rule
Introduction Rendaku is a process of voicing the initial obstruent of the second member of a compound word in Japanese (e.g. hon ‘book’ + tana ‘shelf’→hon-dana). Even though rendaku applies productively to compounds whose second members are nouns of native Japanese origin (i.e. not foreign borrowings), a couple of factors are known to hinder rendaku [1,2]. First, a small number of lexically specified nouns of native Japanese origin do not undergo rendaku [‘rendaku-immune (R-immune) words’, e.g. hime ‘princess’]. Second, when the second member of a compound contains a voiced obstruent, rendaku does not occur (Lyman’s law). There has been an extensive debate in neurolinguistic and psycholinguistic literature as to whether the processing of complex words involves rule application as well as lexical memory. In particular, the Dual Mechanism Model argues that two qualitatively different processes are involved; for instance, English regular -ed past form inflection is dealt with by rule application, whereas irregular past inflection (e.g. sing/sang) is by lexical memory [3]. However, the Single Mechanism Model argues that the same memory-based system can deal with both regular and irregular inflection [4]. Even though rendaku, a phonological process observed in compounds, may seem to bear little connection with inflectional processes, careful consideration of the following two opposing views so far proposed on rendaku shows its relevance to the above controversy. On the one hand, there are many irregularities in rendaku application: in addition to R-immune words, some words resist rendaku more frequently than others, and it is also 0959-4965 © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
application. NeuroReport 25:1296–1301 © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins. NeuroReport 2014, 25:1296–1301 Keywords: Japanese compounds, LAN, lexical memory, N400, rendaku voicing, rule application a Center for Evolutionary Cognitive Sciences, bDepartment of Language and Information Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo and cFaculty of Economics, Keio University, Yokohama, Japan
Correspondence to Yuki Kobayashi, PsyM, Center for Evolutionary Cognitive Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 1538902 Japan Tel: + 81 3 5454 6709; fax: + 81 3 5454 6701; e-mail: [email protected] Received 1 August 2014 accepted 18 August 2014
observed that the same noun can show variable behaviors as in the case of the word hara ‘field’, which gets voiced in matu-bara ‘pine-tree field’ but not in kusa-hara ‘grass field’ [5]. This has led to a lexical analysis, where lexical specification is supposed to determine rendaku application; this is supported by the results of a production experiment suggesting that application of rendaku to novel compounds is determined by lexical analogy to existing compounds [6]. This view of rendaku is compatible with the Single Mechanism Model. On the other hand, rendaku is a highly productive phonological process, and hence is arguably rule-based [7]. This is supported by the results of a production experiment where it was observed that children with specific language impairment, a developmental language disorder whose typical weakness lies in rule-based processing such as regular inflection, applied rendaku to novel compounds much less frequently than children without specific language impairment [8]. According to this rule-based view, even though the lexical irregularities mentioned above must be dealt with by lexical memory, rendaku uses rule application in regular cases or in novel compounds, a view in line with the Dual Mechanism Model. Previous event-related potential (ERP) studies on regular and irregular inflection in the framework of the Dual Mechanism Model have shown that the measurement of ERP responses to violations (wrongly inflected forms) provides a way to differentiate rule-based processes and lexical analogy. Three ERP components, N400, left anterior negativity (LAN), and P600, are known to be related to language processing. The N400 is a negativity that peaks at around DOI: 10.1097/WNR.0000000000000262
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Rendaku voicing as rule application Kobayashi et al. 1297
400 ms after the onset of stimuli with wide, often posterior-centered distribution, and is known to reflect semantic or pragmatic anomaly and to be related to the search of lexical memory [9]. The LAN component is also a negativity observed at around 300–500 ms after the onset of stimuli: it is distinguished from the N400 in its distribution, which is limited to the left anterior region. This component is known to reflect morphosyntactic anomalies such as agreement errors [10]. The P600 is a positive component observed at around 600 ms after the onset of stimuli. Both anterior and posterior distributions have been reported. This component has been claimed to reflect the process of reanalysis or repair in the face of morphosyntactic or syntactic violations of various types [11,12]. According to previous studies in the Dual Mechanism Model, inappropriately attached regular inflectional suffixes (e.g. *bringed instead of brought, which is considered ‘over-regularization’, namely, overapplication of rule) have been shown to robustly elicit a LAN in English [13] and German [14,15]. However, analogical extension of irregular inflectional patterns (e.g. *glew instead of glowed, which is considered ‘overirregularization’) has yielded somewhat varied results, including the elicitation of an N400-like component ([14], cf. [13]) and no consistent effects [15]. Thus, we may interpret the LAN component as a highly reliable reflection of the ‘over-regularizationtype violation, whereas the corresponding reflection of the ‘overirregularization’ type is not so clear-cut. In sum, the ERP responses to violations can offer a clue to differentiate rule-based computation from analogical processes on the basis of lexical memory.
Experimental design Building on these findings, we devised an ERP experiment whereby we investigated the processing of compound words with rendaku violation by recording ERP responses to three different types of violations in comparison with the well-formed counterparts, as shown below (GEN: genitive case particle, NOM: nominative case particle, TOP: topic marker, COP: copula, ACC: accusative case particle): in type I (R-immune), rendaku voicing was applied wrongly to R-immune words. In type II (Lyman), rendaku was applied against Lyman’s law. In type III (No-R), rendaku failed to apply where there is no hindering factor.
Type II: Lyman violation (with a voiced obstruent in the second element)
Tyasitu-no kabe-wa huuryuuna suna-(kabe/*gabe)-ni natteita. tea.room-GEN wall-TOP elegant sand-wall-COP was (The wall of the tea room was an elegant sand wall.) Type III: No-R-application
Urimono-no nozoita.
kai-kara
kotubu-no
goods.for.sale-GEN shellfish-from shellfish-ACC removed
mame-(*kai/gai)-o small-GEN
pea-
[(We) removed small shellfish from shellfish for sale.]
Prediction If rendaku is rule-based, wrongly voiced forms in type I (R-immune) and type II (Lyman) can be predicted to elicit a LAN (and a P600) because these are overregularizations of rendaku voicing. It is also predicted that type III (No-R) yields a different response from type I and type II as not applying otherwise productive rendaku amounts to over-irregularizations of memorybased rendaku-blocking. In contrast, if rendaku is lexical, it is predicted that no difference is observed among the three types of violation.
Methods Twenty-five (17 men and eight women; age range 19–21 years; mean 19.81 years) Japanese undergraduate students at the University of Tokyo were paid to participate in the experiment after providing informed consent. All were right-handed and had normal or correctedto-normal vision. The research was approved by the Ethics Committee on Human Subjects Research of the College of Arts and Sciences, the University of Tokyo.
lake-GEN princess-and sister-GEN sea-princess-NOM appeared
We chose 10 nouns of native Japanese origin as the righthand components of compound words for each type of violation. Each noun was combined with eight different left component words to produce eight compounds, resulting in 80 compounds for each type. It was ensured that all combinations yielded novel-sounding compounds not likely to be listed in the lexicon of the participants. Stimuli in each violation type comprised two conditions: one with inappropriate application (type I, type II) and nonapplication (type III) of rendaku, and the other with appropriate nonapplication (type I, type II) and application (type III) thereof. These stimuli were shown to two groups of participants in a latin square design, where each participant read 240 sentences in total, half with appropriate compounds and the other half with inappropriate ones. We controlled the familiarity of all nouns and naturalness of all sentences.
(The princess of the lake and her sister the princess of sea appeared.)
Electroencephalogram (EEG) signals were recorded while the participants read the stimulus sentences shown
Type I: voiced R-immune words
Mizuumi-no arawareta.
hime-to
ane-no
umi-(hime/*bime)-ga
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NeuroReport 2014, Vol 25 No 16
Recordings were referenced to the electrode located between Cz and CPz and then re-referenced off-line to the average of the left and right mastoids. Electrode impedance was maintained below 10 kΩ. ERP averages were computed with a 100 ms baseline and an 800 ms ERP time window.
automatically on the PC screen phrase by phrase. They were asked to refrain from blinking their eyes or moving their bodies until the end of the sentences. Each sentence had five phrases and each phrase appeared on the screen for 600 ms with a 200 ms blank between each phrase. The critical word was the fourth phrase in the stimulus sentences. Following the presentation of a sentence, participants were instructed to make a naturalness judgment (yes/no decision) by clicking a computer mouse. The 240 sentences were divided into four blocks, and within the blocks, sentences were randomized. The participants took a short break after each block.
Data analysis
Trials for which the yes/no question was not answered correctly were excluded from the averaging procedure, as were trials containing artifacts (the EOG rejection criterion was 100 μV). Participants showing high rates (>40%) of artifacts and/or error responses to the yes/no questions were excluded from the analysis. Six participants were excluded and the data from the remaining 15 participants (11 men and four women) were analyzed.
EEG signals were recorded from 60 Ag/AgCl electrodes mounted in an elastic cap (NeuroScan Quikcap, Compumedics, Charlotte, North Carolina, USA) according to the International 10–20 system. To control the participants’ horizontal and vertical eye movements, a bipolar electrooculogram (EOG) was also recorded using four electrodes. All the EEG and EOG channels were digitized at a 250 Hz sampling rate using a Neuroscan Synamp2s (Compumedics, Charlotte, North Carolina, USA) amplifier with a band-pass between DC and 70 Hz.
All the analyses of variance included the factors of condition (COND: rendaku vs. non-rendaku), hemisphere (HEMI: left vs. right), and region (REG: anterior vs. posterior). Visual inspection showed that the negativity in type I had its focus in a limited area of the peripheral left frontal region, whereas the negativity in type III and the
Fig. 1
F7
F8
LAN
P7
P8
P600
−8
μV s
−4 0
0.2
0.4
0.6
0.8
F7
F8
P7
P8
0 4 8
Non-rendaku (correct) Rendaku
12 Grand-average event-related potentials (ERPs) relative to target compound words (onset at the vertical bar) for the non-rendaku (black line) versus the rendaku (gray line) for type I (R-immune). ERPs are shown at selected electrodes indicated in the electrode map. Negativity is plotted upwards. LAN, left anterior negativity.
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Rendaku voicing as rule application Kobayashi et al. 1299
positivities in types I and II were more centrally focused. On the basis of this observation, we chose the following lateral four regions of interest (ROIs) on the basis of hemisphere (left/right) and region (anterior/posterior): for the analysis of the left-lateralized negativity in type I, left-anterior (FP1, AF3, F7, and FT7), left-posterior (TP7, P7, PO3, and O1), right-anterior (FP2, AF4, F8, and FT8), and right-posterior (TP7, P7, PO3, and O1); and for the analysis of the negativity in type III and the positivities in types I and II, left-anterior (F5, F3, F1, FC5, FC3, and FC1), left-posterior (CP5, CP3, CP1, P5, P3, and P1), right-anterior (F2, F4, F6, FC2, FC4, and FC6), and right-posterior (CP2, CP4, CP6, P2, P4, and P6).
Results Type I: voiced R-immune words
Figure 1 shows the grand average ERPs for the target compound words of type I (R-immune). As shown in Fig. 1, the rendaku condition, when compared with the correct non-rendaku condition, elicited a negativity in the left anterior region at the time range of 300–600 ms and a
positivity in the posterior region around 400–800 ms. The analyses for the time window 300–600 ms showed a significant interaction between HEMI and REG and COND [F(1,15) = 6.37, P < 0.05]. Planned comparisons for each of the four ROIs showed that the rendaku condition was more negative-going than the non-rendaku condition in the left anterior site [F(1,15) = 8.70, P < 0.005]. The latency and the distribution of the negativity suggest that it is a LAN component. The analyses for the time window 400–800 ms showed a significant interaction between REG and COND [F(1,15) = 7.29, P < 0.05]. Planned comparisons for each of the four ROIs showed that the rendaku condition was more positive-going than the non-rendaku condition in the posterior site [F(1,15) = 5.89, P < 0.05]. The latency and the distribution of the positivity suggest that it is a P600 component. Type II: Lyman violation
Figure 2 shows the grand average ERPs for the target compound words of type II (Lyman). As shown in Fig. 2, the rendaku condition, when compared with the correct
Fig. 2
F4
F3
P3
P4
P600 −8
μV
−4 0
0.2
0.4
0.6
s 0.8
F3
F4
P3
P4
0 4 8
Non-rendaku (correct) Rendaku
12 Grand-average event-related potentials (ERPs) relative to target compound words (onset at the vertical bar) for the non-rendaku (black line) versus the rendaku (gray line) for type II (Lyman). ERPs are shown at selected electrodes indicated in the electrode map. Negativity is plotted upwards.
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1300 NeuroReport 2014, Vol 25 No 16
Fig. 3
F3
F4
P3
P4
N400 −8 −4
μV 0
0.2
0.4
0.6
s 0.8
F3
F4
P3
P4
0 4 8
Non-rendaku Rendaku (correct)
12 Grand-average event-related potentials (ERPs) relative to target compound words (onset at the vertical bar) for the non-rendaku (black line) versus the rendaku (gray line) for type III (No-R). ERPs are shown at selected electrodes indicated in the electrode map. Negativity is plotted upwards.
non-rendaku condition, elicited a positivity in the posterior region in the time range of 400–800 ms. The analyses for the time window 400–800 ms showed significant interactions between REG and COND [F(1,15) = 27.10, P < 0.005] and between HEMI and COND [F(1,15) = 6.79, P < 0.05]. Planned comparisons for each of the four ROIs showed main effects of COND for the posterior site [F(1,15) = 8.70, P < 0.005], for the left site [F(1,15) = 4.89, P < 0.05], and for the right site [F(1,15) = 12.77, P < 0.005]. The rendaku condition was more positive-going than the non-rendaku condition. The latency and the distribution of the positivity suggest that it is a P600 component. Type III: No-R-application
Figure 3 shows the grand average ERPs for the target compound words of type III (no-R). As shown in Fig. 3, the non-rendaku condition, when compared with the correct rendaku condition, elicited a broad negativity in the time range of 300–800 ms. The analyses for the time window 300–800 ms showed a main effect of COND [F(1,15) = 11.37, P < 0.005]. The non-rendaku condition was more negative-going than the rendaku condition.
The distribution of the negativity was not limited to the left anterior region (i.e. no interaction was observed between COND and HEMI or between COND and REG), which suggests that it is an N400 component.
Discussion Our results basically support the claim based on the Dual Mechanism Model, namely, rendaku in novel compounds involves rule application rather than lexical analogy. First, a LAN component was observed in type I (R-immune). Given the results of previous ERP studies on regular/ irregular dichotomy surveyed in the Introduction section, this finding can be interpreted as indicating that the application of rendaku to R-immune words is a case of over-regularization in the sense that the rule of rendaku voicing is applied to words lexically specified to resist rendaku. Second, P600 components were observed both in type I (R-immune) and in type II (Lyman), and can be considered as a reflection of the process of reanalysis for the incorrect rendaku-forms. This is consistent with previous studies reporting P600s for overapplication of rules [13]. However, we did not observe a LAN component in type II (Lyman) contra our prediction. This may be
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Rendaku voicing as rule application Kobayashi et al. 1301
because Lyman’s law is part of a more general phonological constraint barring multiple-voiced obstruents in a certain metrical domain [1]. This point is left for future study. It also supports the rule-based view of rendaku that type III (No-R) yielded a different component (N400) from types I and II. As the resistance to rendaku application is lexically governed as in R-immune words or other variable cases, nonapplication of rendaku in type III can be interpreted as a case of overirregularization (i.e. overapplication of lexically determined resistance to rendaku), which is consistent with some previous reports [14].
process observed in the former is likely to reflect a conscious process of ‘afterthought’, whereas ERP responses in the latter can tap into more unconscious processes in online parsing. Hence, we may safely conclude that rendaku in novel compounds does involve rule application at the unconscious level of processing.
Acknowledgements This work was supported by JSPS KAKENHI Grant Numbers 20320069, 25284089 to Yoko Sugioka and Takane Ito. Conflicts of interest
Conclusion The results of our present ERP study lend support to the claim that rendaku in novel compounds involves rule application. This claim can be considered as adding a new angle to the Dual Mechanism hypothesis, which has so far focused mainly on the study of inflectional morphology, by showing that rendaku, a phonological process accompanying a word-formation process, uses the mental mechanism of rule-based computation. Framing the rendaku phenomenon in the Dual Mechanism hypothesis has allowed us to compare our ERP results with the previous works on German and English inflection [13–15]. The phenomenon of rendaku may appear totally dissimilar to inflection, and yet they are also operations affecting word forms, and hence it is not surprising that they can be accounted for in the same framework of the Dual Mechanism Model. With this reasoning, we are able to provide a new piece of evidence in support of the rule-based analysis of rendaku application. It should also be noted that we have introduced a new way of soliciting responses to rendaku forms with ERP measurement. Experimental studies on rendaku have so far mostly been limited to some versions of off-line elicitation tasks, where participants can take time to consciously consider how to react. Thus, the discrepancy between the results of such elicitation tasks [6] and those of our ERP experiment might be attributable to the difference in the experimental methods: an analogical
There are no conflicts of interest.
References 1
2 3 4
5 6 7 8
9 10
11 12 13 14
15
Kubozono H. Rendaku: its domain and linguistic conditions. In: Weijer J, Nanjo K, Nishihara T, editors. Voicing in Japanese. Berlin: Mouton de Gruyter; 2005. pp. 5–20. Vance TJ. An introduction to Japanese phonology. Albany: SUNY Press; 1987. Pinker S, Ullman MT. The past and future of the past tense. Trends Cogn Sci 2002; 6:456–463. Joanisse MF, Seidenberg MS. Impairments in verb morphology after brain injury: a connectionist model. Proc Natl Acad Sci USA 1999; 96:7592–7597. Rosen E. Systematic irregularities in rendaku: how the grammar mediates patterned lexical exceptions. Can J Linguist 2003; 48:1–37. Ohno K. The lexical nature of rendaku in Japanese. JPN/Korean Linguist 2000; 9:151–164. Ito J, Mester RA. The phonology of voicing in Japanese: theoretical consequences for morphological accessibility. Linguist Inq 1986; 17:48–73. Fukuda S, Fukuda S. To voice or not to voice: the operation of rendaku in the Japanese developmentally language-impaired. McGill Working Paper in Linguist 1994; 10:178–193. Kutas M, Federmeier KD. Electrophysiology reveals semantic memory use in language comprehension. Trends Cogn Sci 2000; 4:463–470. Coulson S, King JW, Kutas M. Expect the unexpected: event-related brain response to morphosyntactic violations. Lang Cognitive Proc 1998; 13:21–58. Osterhout L, Holcomb PJ. Event-related brain potentials elicited by syntactic anomaly. J Mem Lang 1992; 31:785–806. Hagoort P, Brown C, Groothusen J. The syntactic positive shift as an ERP measure of syntactic processing. Lang Cognitive Proc 1993; 8:439–484. Morris J, Holcomb PJ. Event-related potentials to violations of inflectional verb morphology in English. Brain Res Cogn Brain Res 2005; 25:963–981. Weyerts H, Penke M, Dohrn U, Clahsen H, Münte TF. Brain potentials indicate differences between regular and irregular German plurals. Neuroreport 1997; 8:957–962. Penke M, Weyerts H, Gross M, Zander E, Münte TF, Clahsen H. How the brain processes complex words: an event-related potential study of German verb inflections. Brain Res Cogn Brain Res 1997; 6:37–52.
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Integrative systems
Rendaku (Japanese sequential voicing) as rule application: an ERP study Yuki Kobayashia, Yoko Sugiokac and Takane Itoa,b Japanese sequential voicing (rendaku) is a process of voicing the initial obstruent of the second member of a compound word in Japanese (e.g. hon ‘book’ + tana ‘shelf’→hon-dana). We conducted an event-related potential measurement experiment to investigate whether rendaku is a regular process of rule application or an analogical process based on lexical memory. When rendaku was applied wrongly to words lexically specified to resist rendaku, a left anterior negativity component, followed by a P600 was observed, whereas applying rendaku against a phonological constraint known as Lyman’s law elicited a P600 component alone. Failure of rendaku application where it should apply yielded an N400. These results suggest that rendaku is a process involving rule
Introduction Rendaku is a process of voicing the initial obstruent of the second member of a compound word in Japanese (e.g. hon ‘book’ + tana ‘shelf’→hon-dana). Even though rendaku applies productively to compounds whose second members are nouns of native Japanese origin (i.e. not foreign borrowings), a couple of factors are known to hinder rendaku [1,2]. First, a small number of lexically specified nouns of native Japanese origin do not undergo rendaku [‘rendaku-immune (R-immune) words’, e.g. hime ‘princess’]. Second, when the second member of a compound contains a voiced obstruent, rendaku does not occur (Lyman’s law). There has been an extensive debate in neurolinguistic and psycholinguistic literature as to whether the processing of complex words involves rule application as well as lexical memory. In particular, the Dual Mechanism Model argues that two qualitatively different processes are involved; for instance, English regular -ed past form inflection is dealt with by rule application, whereas irregular past inflection (e.g. sing/sang) is by lexical memory [3]. However, the Single Mechanism Model argues that the same memory-based system can deal with both regular and irregular inflection [4]. Even though rendaku, a phonological process observed in compounds, may seem to bear little connection with inflectional processes, careful consideration of the following two opposing views so far proposed on rendaku shows its relevance to the above controversy. On the one hand, there are many irregularities in rendaku application: in addition to R-immune words, some words resist rendaku more frequently than others, and it is also 0959-4965 © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
application. NeuroReport 25:1296–1301 © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins. NeuroReport 2014, 25:1296–1301 Keywords: Japanese compounds, LAN, lexical memory, N400, rendaku voicing, rule application a Center for Evolutionary Cognitive Sciences, bDepartment of Language and Information Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo and cFaculty of Economics, Keio University, Yokohama, Japan
Correspondence to Yuki Kobayashi, PsyM, Center for Evolutionary Cognitive Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 1538902 Japan Tel: + 81 3 5454 6709; fax: + 81 3 5454 6701; e-mail: [email protected] Received 1 August 2014 accepted 18 August 2014
observed that the same noun can show variable behaviors as in the case of the word hara ‘field’, which gets voiced in matu-bara ‘pine-tree field’ but not in kusa-hara ‘grass field’ [5]. This has led to a lexical analysis, where lexical specification is supposed to determine rendaku application; this is supported by the results of a production experiment suggesting that application of rendaku to novel compounds is determined by lexical analogy to existing compounds [6]. This view of rendaku is compatible with the Single Mechanism Model. On the other hand, rendaku is a highly productive phonological process, and hence is arguably rule-based [7]. This is supported by the results of a production experiment where it was observed that children with specific language impairment, a developmental language disorder whose typical weakness lies in rule-based processing such as regular inflection, applied rendaku to novel compounds much less frequently than children without specific language impairment [8]. According to this rule-based view, even though the lexical irregularities mentioned above must be dealt with by lexical memory, rendaku uses rule application in regular cases or in novel compounds, a view in line with the Dual Mechanism Model. Previous event-related potential (ERP) studies on regular and irregular inflection in the framework of the Dual Mechanism Model have shown that the measurement of ERP responses to violations (wrongly inflected forms) provides a way to differentiate rule-based processes and lexical analogy. Three ERP components, N400, left anterior negativity (LAN), and P600, are known to be related to language processing. The N400 is a negativity that peaks at around DOI: 10.1097/WNR.0000000000000262
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Rendaku voicing as rule application Kobayashi et al. 1297
400 ms after the onset of stimuli with wide, often posterior-centered distribution, and is known to reflect semantic or pragmatic anomaly and to be related to the search of lexical memory [9]. The LAN component is also a negativity observed at around 300–500 ms after the onset of stimuli: it is distinguished from the N400 in its distribution, which is limited to the left anterior region. This component is known to reflect morphosyntactic anomalies such as agreement errors [10]. The P600 is a positive component observed at around 600 ms after the onset of stimuli. Both anterior and posterior distributions have been reported. This component has been claimed to reflect the process of reanalysis or repair in the face of morphosyntactic or syntactic violations of various types [11,12]. According to previous studies in the Dual Mechanism Model, inappropriately attached regular inflectional suffixes (e.g. *bringed instead of brought, which is considered ‘over-regularization’, namely, overapplication of rule) have been shown to robustly elicit a LAN in English [13] and German [14,15]. However, analogical extension of irregular inflectional patterns (e.g. *glew instead of glowed, which is considered ‘overirregularization’) has yielded somewhat varied results, including the elicitation of an N400-like component ([14], cf. [13]) and no consistent effects [15]. Thus, we may interpret the LAN component as a highly reliable reflection of the ‘over-regularizationtype violation, whereas the corresponding reflection of the ‘overirregularization’ type is not so clear-cut. In sum, the ERP responses to violations can offer a clue to differentiate rule-based computation from analogical processes on the basis of lexical memory.
Experimental design Building on these findings, we devised an ERP experiment whereby we investigated the processing of compound words with rendaku violation by recording ERP responses to three different types of violations in comparison with the well-formed counterparts, as shown below (GEN: genitive case particle, NOM: nominative case particle, TOP: topic marker, COP: copula, ACC: accusative case particle): in type I (R-immune), rendaku voicing was applied wrongly to R-immune words. In type II (Lyman), rendaku was applied against Lyman’s law. In type III (No-R), rendaku failed to apply where there is no hindering factor.
Type II: Lyman violation (with a voiced obstruent in the second element)
Tyasitu-no kabe-wa huuryuuna suna-(kabe/*gabe)-ni natteita. tea.room-GEN wall-TOP elegant sand-wall-COP was (The wall of the tea room was an elegant sand wall.) Type III: No-R-application
Urimono-no nozoita.
kai-kara
kotubu-no
goods.for.sale-GEN shellfish-from shellfish-ACC removed
mame-(*kai/gai)-o small-GEN
pea-
[(We) removed small shellfish from shellfish for sale.]
Prediction If rendaku is rule-based, wrongly voiced forms in type I (R-immune) and type II (Lyman) can be predicted to elicit a LAN (and a P600) because these are overregularizations of rendaku voicing. It is also predicted that type III (No-R) yields a different response from type I and type II as not applying otherwise productive rendaku amounts to over-irregularizations of memorybased rendaku-blocking. In contrast, if rendaku is lexical, it is predicted that no difference is observed among the three types of violation.
Methods Twenty-five (17 men and eight women; age range 19–21 years; mean 19.81 years) Japanese undergraduate students at the University of Tokyo were paid to participate in the experiment after providing informed consent. All were right-handed and had normal or correctedto-normal vision. The research was approved by the Ethics Committee on Human Subjects Research of the College of Arts and Sciences, the University of Tokyo.
lake-GEN princess-and sister-GEN sea-princess-NOM appeared
We chose 10 nouns of native Japanese origin as the righthand components of compound words for each type of violation. Each noun was combined with eight different left component words to produce eight compounds, resulting in 80 compounds for each type. It was ensured that all combinations yielded novel-sounding compounds not likely to be listed in the lexicon of the participants. Stimuli in each violation type comprised two conditions: one with inappropriate application (type I, type II) and nonapplication (type III) of rendaku, and the other with appropriate nonapplication (type I, type II) and application (type III) thereof. These stimuli were shown to two groups of participants in a latin square design, where each participant read 240 sentences in total, half with appropriate compounds and the other half with inappropriate ones. We controlled the familiarity of all nouns and naturalness of all sentences.
(The princess of the lake and her sister the princess of sea appeared.)
Electroencephalogram (EEG) signals were recorded while the participants read the stimulus sentences shown
Type I: voiced R-immune words
Mizuumi-no arawareta.
hime-to
ane-no
umi-(hime/*bime)-ga
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NeuroReport 2014, Vol 25 No 16
Recordings were referenced to the electrode located between Cz and CPz and then re-referenced off-line to the average of the left and right mastoids. Electrode impedance was maintained below 10 kΩ. ERP averages were computed with a 100 ms baseline and an 800 ms ERP time window.
automatically on the PC screen phrase by phrase. They were asked to refrain from blinking their eyes or moving their bodies until the end of the sentences. Each sentence had five phrases and each phrase appeared on the screen for 600 ms with a 200 ms blank between each phrase. The critical word was the fourth phrase in the stimulus sentences. Following the presentation of a sentence, participants were instructed to make a naturalness judgment (yes/no decision) by clicking a computer mouse. The 240 sentences were divided into four blocks, and within the blocks, sentences were randomized. The participants took a short break after each block.
Data analysis
Trials for which the yes/no question was not answered correctly were excluded from the averaging procedure, as were trials containing artifacts (the EOG rejection criterion was 100 μV). Participants showing high rates (>40%) of artifacts and/or error responses to the yes/no questions were excluded from the analysis. Six participants were excluded and the data from the remaining 15 participants (11 men and four women) were analyzed.
EEG signals were recorded from 60 Ag/AgCl electrodes mounted in an elastic cap (NeuroScan Quikcap, Compumedics, Charlotte, North Carolina, USA) according to the International 10–20 system. To control the participants’ horizontal and vertical eye movements, a bipolar electrooculogram (EOG) was also recorded using four electrodes. All the EEG and EOG channels were digitized at a 250 Hz sampling rate using a Neuroscan Synamp2s (Compumedics, Charlotte, North Carolina, USA) amplifier with a band-pass between DC and 70 Hz.
All the analyses of variance included the factors of condition (COND: rendaku vs. non-rendaku), hemisphere (HEMI: left vs. right), and region (REG: anterior vs. posterior). Visual inspection showed that the negativity in type I had its focus in a limited area of the peripheral left frontal region, whereas the negativity in type III and the
Fig. 1
F7
F8
LAN
P7
P8
P600
−8
μV s
−4 0
0.2
0.4
0.6
0.8
F7
F8
P7
P8
0 4 8
Non-rendaku (correct) Rendaku
12 Grand-average event-related potentials (ERPs) relative to target compound words (onset at the vertical bar) for the non-rendaku (black line) versus the rendaku (gray line) for type I (R-immune). ERPs are shown at selected electrodes indicated in the electrode map. Negativity is plotted upwards. LAN, left anterior negativity.
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Rendaku voicing as rule application Kobayashi et al. 1299
positivities in types I and II were more centrally focused. On the basis of this observation, we chose the following lateral four regions of interest (ROIs) on the basis of hemisphere (left/right) and region (anterior/posterior): for the analysis of the left-lateralized negativity in type I, left-anterior (FP1, AF3, F7, and FT7), left-posterior (TP7, P7, PO3, and O1), right-anterior (FP2, AF4, F8, and FT8), and right-posterior (TP7, P7, PO3, and O1); and for the analysis of the negativity in type III and the positivities in types I and II, left-anterior (F5, F3, F1, FC5, FC3, and FC1), left-posterior (CP5, CP3, CP1, P5, P3, and P1), right-anterior (F2, F4, F6, FC2, FC4, and FC6), and right-posterior (CP2, CP4, CP6, P2, P4, and P6).
Results Type I: voiced R-immune words
Figure 1 shows the grand average ERPs for the target compound words of type I (R-immune). As shown in Fig. 1, the rendaku condition, when compared with the correct non-rendaku condition, elicited a negativity in the left anterior region at the time range of 300–600 ms and a
positivity in the posterior region around 400–800 ms. The analyses for the time window 300–600 ms showed a significant interaction between HEMI and REG and COND [F(1,15) = 6.37, P < 0.05]. Planned comparisons for each of the four ROIs showed that the rendaku condition was more negative-going than the non-rendaku condition in the left anterior site [F(1,15) = 8.70, P < 0.005]. The latency and the distribution of the negativity suggest that it is a LAN component. The analyses for the time window 400–800 ms showed a significant interaction between REG and COND [F(1,15) = 7.29, P < 0.05]. Planned comparisons for each of the four ROIs showed that the rendaku condition was more positive-going than the non-rendaku condition in the posterior site [F(1,15) = 5.89, P < 0.05]. The latency and the distribution of the positivity suggest that it is a P600 component. Type II: Lyman violation
Figure 2 shows the grand average ERPs for the target compound words of type II (Lyman). As shown in Fig. 2, the rendaku condition, when compared with the correct
Fig. 2
F4
F3
P3
P4
P600 −8
μV
−4 0
0.2
0.4
0.6
s 0.8
F3
F4
P3
P4
0 4 8
Non-rendaku (correct) Rendaku
12 Grand-average event-related potentials (ERPs) relative to target compound words (onset at the vertical bar) for the non-rendaku (black line) versus the rendaku (gray line) for type II (Lyman). ERPs are shown at selected electrodes indicated in the electrode map. Negativity is plotted upwards.
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1300 NeuroReport 2014, Vol 25 No 16
Fig. 3
F3
F4
P3
P4
N400 −8 −4
μV 0
0.2
0.4
0.6
s 0.8
F3
F4
P3
P4
0 4 8
Non-rendaku Rendaku (correct)
12 Grand-average event-related potentials (ERPs) relative to target compound words (onset at the vertical bar) for the non-rendaku (black line) versus the rendaku (gray line) for type III (No-R). ERPs are shown at selected electrodes indicated in the electrode map. Negativity is plotted upwards.
non-rendaku condition, elicited a positivity in the posterior region in the time range of 400–800 ms. The analyses for the time window 400–800 ms showed significant interactions between REG and COND [F(1,15) = 27.10, P < 0.005] and between HEMI and COND [F(1,15) = 6.79, P < 0.05]. Planned comparisons for each of the four ROIs showed main effects of COND for the posterior site [F(1,15) = 8.70, P < 0.005], for the left site [F(1,15) = 4.89, P < 0.05], and for the right site [F(1,15) = 12.77, P < 0.005]. The rendaku condition was more positive-going than the non-rendaku condition. The latency and the distribution of the positivity suggest that it is a P600 component. Type III: No-R-application
Figure 3 shows the grand average ERPs for the target compound words of type III (no-R). As shown in Fig. 3, the non-rendaku condition, when compared with the correct rendaku condition, elicited a broad negativity in the time range of 300–800 ms. The analyses for the time window 300–800 ms showed a main effect of COND [F(1,15) = 11.37, P < 0.005]. The non-rendaku condition was more negative-going than the rendaku condition.
The distribution of the negativity was not limited to the left anterior region (i.e. no interaction was observed between COND and HEMI or between COND and REG), which suggests that it is an N400 component.
Discussion Our results basically support the claim based on the Dual Mechanism Model, namely, rendaku in novel compounds involves rule application rather than lexical analogy. First, a LAN component was observed in type I (R-immune). Given the results of previous ERP studies on regular/ irregular dichotomy surveyed in the Introduction section, this finding can be interpreted as indicating that the application of rendaku to R-immune words is a case of over-regularization in the sense that the rule of rendaku voicing is applied to words lexically specified to resist rendaku. Second, P600 components were observed both in type I (R-immune) and in type II (Lyman), and can be considered as a reflection of the process of reanalysis for the incorrect rendaku-forms. This is consistent with previous studies reporting P600s for overapplication of rules [13]. However, we did not observe a LAN component in type II (Lyman) contra our prediction. This may be
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Rendaku voicing as rule application Kobayashi et al. 1301
because Lyman’s law is part of a more general phonological constraint barring multiple-voiced obstruents in a certain metrical domain [1]. This point is left for future study. It also supports the rule-based view of rendaku that type III (No-R) yielded a different component (N400) from types I and II. As the resistance to rendaku application is lexically governed as in R-immune words or other variable cases, nonapplication of rendaku in type III can be interpreted as a case of overirregularization (i.e. overapplication of lexically determined resistance to rendaku), which is consistent with some previous reports [14].
process observed in the former is likely to reflect a conscious process of ‘afterthought’, whereas ERP responses in the latter can tap into more unconscious processes in online parsing. Hence, we may safely conclude that rendaku in novel compounds does involve rule application at the unconscious level of processing.
Acknowledgements This work was supported by JSPS KAKENHI Grant Numbers 20320069, 25284089 to Yoko Sugioka and Takane Ito. Conflicts of interest
Conclusion The results of our present ERP study lend support to the claim that rendaku in novel compounds involves rule application. This claim can be considered as adding a new angle to the Dual Mechanism hypothesis, which has so far focused mainly on the study of inflectional morphology, by showing that rendaku, a phonological process accompanying a word-formation process, uses the mental mechanism of rule-based computation. Framing the rendaku phenomenon in the Dual Mechanism hypothesis has allowed us to compare our ERP results with the previous works on German and English inflection [13–15]. The phenomenon of rendaku may appear totally dissimilar to inflection, and yet they are also operations affecting word forms, and hence it is not surprising that they can be accounted for in the same framework of the Dual Mechanism Model. With this reasoning, we are able to provide a new piece of evidence in support of the rule-based analysis of rendaku application. It should also be noted that we have introduced a new way of soliciting responses to rendaku forms with ERP measurement. Experimental studies on rendaku have so far mostly been limited to some versions of off-line elicitation tasks, where participants can take time to consciously consider how to react. Thus, the discrepancy between the results of such elicitation tasks [6] and those of our ERP experiment might be attributable to the difference in the experimental methods: an analogical
There are no conflicts of interest.
References 1
2 3 4
5 6 7 8
9 10
11 12 13 14
15
Kubozono H. Rendaku: its domain and linguistic conditions. In: Weijer J, Nanjo K, Nishihara T, editors. Voicing in Japanese. Berlin: Mouton de Gruyter; 2005. pp. 5–20. Vance TJ. An introduction to Japanese phonology. Albany: SUNY Press; 1987. Pinker S, Ullman MT. The past and future of the past tense. Trends Cogn Sci 2002; 6:456–463. Joanisse MF, Seidenberg MS. Impairments in verb morphology after brain injury: a connectionist model. Proc Natl Acad Sci USA 1999; 96:7592–7597. Rosen E. Systematic irregularities in rendaku: how the grammar mediates patterned lexical exceptions. Can J Linguist 2003; 48:1–37. Ohno K. The lexical nature of rendaku in Japanese. JPN/Korean Linguist 2000; 9:151–164. Ito J, Mester RA. The phonology of voicing in Japanese: theoretical consequences for morphological accessibility. Linguist Inq 1986; 17:48–73. Fukuda S, Fukuda S. To voice or not to voice: the operation of rendaku in the Japanese developmentally language-impaired. McGill Working Paper in Linguist 1994; 10:178–193. Kutas M, Federmeier KD. Electrophysiology reveals semantic memory use in language comprehension. Trends Cogn Sci 2000; 4:463–470. Coulson S, King JW, Kutas M. Expect the unexpected: event-related brain response to morphosyntactic violations. Lang Cognitive Proc 1998; 13:21–58. Osterhout L, Holcomb PJ. Event-related brain potentials elicited by syntactic anomaly. J Mem Lang 1992; 31:785–806. Hagoort P, Brown C, Groothusen J. The syntactic positive shift as an ERP measure of syntactic processing. Lang Cognitive Proc 1993; 8:439–484. Morris J, Holcomb PJ. Event-related potentials to violations of inflectional verb morphology in English. Brain Res Cogn Brain Res 2005; 25:963–981. Weyerts H, Penke M, Dohrn U, Clahsen H, Münte TF. Brain potentials indicate differences between regular and irregular German plurals. Neuroreport 1997; 8:957–962. Penke M, Weyerts H, Gross M, Zander E, Münte TF, Clahsen H. How the brain processes complex words: an event-related potential study of German verb inflections. Brain Res Cogn Brain Res 1997; 6:37–52.
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