Greater Left Inferior Frontal Activation for SVO than VOS during Sentence Comprehension in Kaqchikel.

Masatoshi Koizumi,Jungho Kim

doi:10.3389/fpsyg.2016.01541

Abstract

Cortical activations during the processing of Kaqchikel transitive sentences with canonical and non-canonical word orders were investigated using functional magnetic resonance imaging. Kaqchikel is an endangered Mayan language spoken in Guatemala. The word order in this language is relatively flexible. We observed higher cortical activations in the left inferior frontal gyrus for sentences with the subject-verb-object (SVO) word order, as compared to sentences with the verb-object-subject (VOS) word order, suggesting that Kaqchikel sentences are easier to process when they have the VOS order than when they have the SVO order. This supports the traditional analysis of Mayan word order: the syntactically simplest word order of transitive sentences in Mayan languages, including Kaqchikel, is VOS. More importantly, the results revealed that the subject-before-object word order preference in sentence comprehension, previously observed in other languages, might not reflect a universal aspect of human languages. Rather, processing preference may be language-specific to some extent, reflecting syntactic differences in individual languages.

Highlights

It has been reported that in many flexible word order languages, sentences with a transitive verb (V) induce a lower processing load when the subject (S) precedes the object (O) (SO WORD ORDER = SOV, SVO, VSO) than when the opposite occurs (OS WORD ORDER = OSV, OVS, VOS)
Recall that universal cognition theory suggests that SO word orders should be easier to process than OS word orders, regardless of the basic word order of any individual language
What is the case in Kaqchikel? As we have previously argued in Koizumi et al (2014) and Yasunaga et al (2015), in Kaqchikel, VOS is the syntactically basic word order, and it is associated with simpler syntactic structures than SVO or any other order

Summary

Introduction

It has been reported that in many flexible word order languages, sentences with a transitive verb (V) induce a lower processing load when the subject (S) precedes the object (O) (SO WORD ORDER = SOV, SVO, VSO) than when the opposite occurs (OS WORD ORDER = OSV, OVS, VOS). Behavioral studies have found that OSV sentences take longer to process than SOV sentences in Japanese (Mazuka et al, 2002; Tamaoka et al, 2005). Studies with functional magnetic resonance imaging (fMRI) have reported greater activations of the left inferior frontal gyrus (left IFG) during the processing of OS sentences compared to SO sentences (Grewe et al, 2007 for German; Kinno et al, 2008 and Kim et al, 2009 for Japanese). Event-related potentials (ERP) research has found that OS orders, relative to SO orders, elicit a (sustained) anterior negativity and/or P600, suggesting that processing OS word orders incurs a larger working memory load (Roesler et al, 1998 for German; Ueno and Kluender, 2003 and Hagiwara et al, 2007 for Japanese; Erdocia et al, 2009 for Basque).

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Results

Discussion

Conclusion