Диссертация (Experimental study of several core concepts of theoretical morphology (on the material of russian) - regularity, syncretism, markedness), страница 12

When an irregular form is produced successfully, thestem is simply taken from memory, which is the easiest option forthe morphological processing system. But when somebody cannotfind the right form and tries to derive it somehow, it is more taxingfor the system than dealing with a regular form because the patternis infrequent and unproductive. In this light, the absence of similar findings in Stamatakis et al.’s (2005) study is expected: differenttrial types did not differ significantly in terms of processing loadin their experiment. This could be due to the fact that Stamatakiset al.

(2005) examined comprehension, where one does not have tofind or derive any forms. In general, passive comprehension mightrequire more shallow processing than production, and low-statusrules or morphological patterns associated with IVs in associativememory might get activated only in the latter case, but not in theformer.Let us briefly comment on the opposite results from Tyler et al.(2005) and Slioussar et al. (2014). The fronto-temporal languagerelated areas were activated more for irregulars in the former andwww.frontiersin.org33February 2015 | Volume 9 | Article 36 | 7Kireev et al.A PPI study of Russian verb productionfor irregulars in the latter study. We attributed our findings to processing difficulty (more details above in Section “Previous StudiesTesting the SR and DR Approaches on Russian”), while Tyler et al.(2005) explained theirs by regularity.

In the light of the Section“Discussion” above, we conclude that in both cases, the increasedactivity levels might reflect greater engagement of the morphological processing system (this does not contradict the conclusionsmade in these studies and only clarifies the picture).

In English,regular forms rely on it more than irregular ones because the former are morphologically complex, while the latter are simplex anddo not require any morphological processing at all. In Russian,all forms are morphologically complex, but when people cannotretrieve an irregular form or try to construct a form from a nonceverb, especially from an INV, the morphological processing systemhas to work harder.Now, what do our conclusions mean for the DR and SRapproaches? In the SR approach, only the frequency of a morphological pattern really matters.

In this respect, regular stimuli hadthe same properties in both PPI studies, yet the results diverged.The canonical version of the DR approach postulates one defaultrule and argues that all other forms are stored in memory. Again,prima facie this does not predict any differences between regularstimuli in the two studies.

One could go on to argue that Russianirregular stimuli must undergo morphological decomposition (atleast to get rid of the infinitival affix), and some combinationof morphological analysis and memory retrieval processes makesthem more difficult than regular stimuli on a certain scale, whileEnglish irregular stimuli are the easiest on this scale because nomorphological analysis is required at all. Potentially, hybrid models with several rules of different status such as the ones in Yang(2002) are better suited to account for the data. As we mentionedin Section “Previous Studies Testing the SR and DR Approacheson Russian,” such models were proposed for Russian based on theresults from behavioral experiments.

In any case, it is clear thatsimplistic views must be discarded.Further studies are needed to give more definitive answers tothe questions above. In particular, the Russian verb system withits numerous classes has much more to offer than what we haveused so far. In the present study, we compared verbs from theleast frequent unproductive classes to verbs from the most frequent productive AJ class. However, Russian has other highlyfrequent productive classes.

This might allow us to explore thenature of the effects we have observed so far in more detail: what(if anything) would be associated with the morphological default,with productivity, with type frequency, with the complexity ofthe morphological pattern (e.g., whether it involves stem andsuffix alternations etc.)? This might eventually let us figure outwhat precisely stands behind the regularity effect. Then it will beclear whether it can be accounted for in terms of the DR or SRapproach.Now let us turn to the results for noun stimuli.

The fact thatthe RN > IN comparison gave no significant results is not surprising, given that the main effect of (ir)regularity also did not reachsignificance for nouns in the factorial analysis in Slioussar et al.(2014). Most probably, this is because the irregular feature we hadto select for our noun stimuli was rather minor – the Russian nounsystem is not very complex in this respect.Frontiers in Human NeuroscienceFinally, let us look at our data in the context of recent researcharguing that fronto-temporal language brain regions are spatiallyand functionally distinct from the domain-general fronto-parietalmultiple demand (MD) system (e.g., Duncan, 2010; Fedorenkoet al., 2013; Fedorenko, 2014). In our study, an increase in connectivity between the LIFGop3 region located in one of the languagespecific areas and the bilateral STG was driven by linguistic properties of the stimuli (regularity in the sense of defaultness, typefrequency and/or productivity).

At the same time, we observedhow connectivity between this very same region and the right ACC,which is argued to be part of the domain-general cognitive controlnetwork, depends on the processing difficulty. As the discussionabove shows, the source of this processing difficulty might also belanguage-specific, namely, it might be a morphological processingdifficulty. However, it has an effect on response selection demands,so the cognitive control network must be invoked. In total, incontrast to recent functional connectivity studies arguing for theindependence of language-related and domain-general cognitivecontrol systems (Blank et al., 2014), our data demonstrate howthese systems can be functionally integrated.To summarize, the present PPI study allowed us to tease apartprocessing difficulty and regularity effects in the domain of inflectional morphology.

We not only observed the processing difficultyeffect we identified earlier in Slioussar et al. (2014), but werealso able to find a novel effect of regularity, and gained a better understanding of these two effects by comparing our studyto the only other published PPI study of inflectional morphology(Stamatakis et al., 2005). In Slioussar et al. (2014) some regularityrelated differences in functional activity could be attenuated by theprocessing load effect, but the PPI analysis was sensitive enoughto reveal such differences in functional connectivity. The presentstudy makes us reconsider some findings from Stamatakis et al.(2005), Slioussar et al.

(2014) and several other previous studies.ACKNOWLEDGMENTSThe study was partially supported by the grant “IntegrativePhysiology” from the Department of Physiological Studies ofthe Russian Academy of Sciences (to Maxim Kireev, Alexander D. Korotkov, and Svyatoslav V. Medvedev) and by the grant#0.38.518.2013 from St. Petersburg State University (to NataliaSlioussar and Tatiana V. Chernigovskaya). We are very grateful tothe reviewers for their most valuable comments.SUPPLEMENTARY MATERIALThe Supplementary Material for this article can be found online at:http://www.frontiersin.org/journal/10.3389/fnhum.2015.00036/abstractREFERENCESBeretta, A., Campbell, C., Carr, T. H., Huang, J., Schmitt, L.

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