Object-extracted Relative Clauses Research Articles

Linguistic complexity and information structure in Korean: Evidence from eye-tracking during reading

The nature of the memory processes that support language comprehension and the manner in which information packaging influences online sentence processing were investigated in three experiments that used eye-tracking during reading to measure the ease of understanding complex sentences in Korean. All three experiments examined reading of embedded complement sentences; the third experiment additionally examined reading of sentences with object-modifying, object-extracted relative clauses. In Korean, both of these structures place two NPs with nominative case marking early in the sentence, with the embedded and matrix verbs following later. The type (pronoun, name or description) of these two critical NPs was varied in the experiments. When the initial NPs were of the same type, comprehension was slowed after participants had read the sentence-final verbs, a finding that supports the view that working memory in language comprehension is constrained by similarity-based interference during the retrieval of information necessary to determine the syntactic or semantic relations between noun phrases and verb phrases. Ease of comprehension was also influenced by the association between type of NP and syntactic position, with the best performance being observed when more definite NPs (pronouns and names) were in a prominent syntactic position (e.g., matrix subject) and less definite NPs (descriptions) were in a non-prominent syntactic position (embedded subject). This pattern provides evidence that the interpretation of sentences is facilitated by consistent packaging of information in different linguistic elements.

Relational processing and working memory capacity in comprehension of relative clause sentences

Previous research has indicated that the cognitive load imposed by tasks in various content domains increases with the complexity of the relational information processed. Sentence comprehension entails processing noun-verb relations to determine who did what to whom. The difficulty of object-extracted relative clause sentences might stem from the complex noun-verb relations they entail. Across three studies, participants read 16 types of object- and subject-extracted relative clause sentences at their own pace and then responded to a comprehension question for each sentence. Relational processing was assessed using a premise integration task or a Latin square task. These tasks predicted comprehension of object-relatives before and after controlling for subject-relatives. Working memory (WM) capacity was assessed using reading span or forward and backward digit span tests. WM tasks predicted comprehension of object-relatives before but not after controlling for subject-relatives. Comprehension of object-relatives relied more heavily on a domain-general capacity to process complex relations than on WM capacity.

The nature of working memory capacity in sentence comprehension: Evidence against domain-specific working memory resources

This paper reports the results of a dual-task experiment which investigates the nature of working memory resources used in sentence comprehension. Participants read sentences of varying syntactic complexity (containing subject- and object-extracted relative clauses) while remembering one or three nouns (similar to or dissimilar from the sentence-nouns). A significant on-line interaction was found between syntactic complexity and similarity between the memory-nouns and the sentence-nouns in the three memory-nouns conditions, such that the similarity between the memory-nouns and the sentence-nouns affected the more complex object-extracted relative clauses to a greater extent than the less complex subject-extracted relative clauses. These results extend Gordon, Hendrick, and Levine’s (2002) report of a trend of such an interaction. The results argue against the domain-specific view of working memory resources in sentence comprehension ( Caplan & Waters, 1999).

Determinants of Bold Signal Correlates of Processing Object-Extracted Relative Clauses

Event-related functional magnetic resonance imaging (fMRI) was used to investigate the determinants of blood oxygenation level-dependent (BOLD) signal correlates of processing relative clauses. Matched pairs of sentences that differed in their processing demands were compared. One member of the pair consisted of a syntactically simpler object- subject (OS) sentence, containing a subject-relativized clause attached to the object noun phrase. The second member of the pair consisted of a syntactically more complex subject-object (SO) sentence, containing an object-relativized clause attached to the subject noun phrase. Participants made plausibility judgments about the sentences in whole sentence visual presentation. Voxel-wise statistical activation maps showed increased BOLD signal in multiple cortical regions for complex compared to simple syntactic structures. This pattern was found for plausible sentences only and, within the set of plausible sentences, for SO sentences in which the head noun of the relative clause was animate and the subject noun of the relative clause was inanimate. These results require a re-interpretation of previous results with the same materials using positron emission tomography.

Depth of lexical-semantic processing and sentential load

The text-change detection task has been used to show that changes are more readily detected for words that fall under narrow focus than broad focus ( Sturt, Sanford, Stewart, & Dawydiak, 2004), and that narrow focus appears to lead to finer semantic distinctions being held in the representation of the word. The present experiments apply the same paradigm to investigate whether sentence processing load also influenced the detection of changes, and whether under a high load, semantic distinctions are held at a more crude (rougher grain) level than under low load. Load comparisons were made through subject- and object-extracted relative clauses (Experiment 1), and through referential load (Experiments 2 and 3). Higher loads resulted in poorer change detection, but the pattern of data differed from that obtained in focus manipulations. Experiment 4 explored the effects of referential load upon comprehension, confirming that comprehension did not break down under high-load conditions. In Experiment 5, the load effect was localized to the embedded verb. These results suggest that the effect of load differs from the effect of focus on lexical processing.

Working memory, animacy, and verb class in the processing of relative clauses

In three eye-movement monitoring experiments, participants’ working memory capacity was assessed and they read sentences containing subject-extracted and object-extracted relative clauses. In Experiment 1, sentences lacked helpful semantic cues, object-relatives were harder to process than subject relatives, and working memory capacity did not moderate syntactic complexity effects. In Experiments 2 and 3, categorical distinctions between critical nouns provided helpful semantic cues to syntactic structure and interpretation. Experiments 2 and 3 showed that helpful semantic cues reduced or eliminated syntactic complexity effects, and that this reduction was not produced by lexical properties of specific verbs. Further, in Experiment 2 working memory capacity moderated the interaction of syntactic complexity and semantic cues.

Processing relative clauses in Chinese

This paper reports results from a self-paced reading study in Chinese that demonstrates that object-extracted relative clause structures are less complex than corresponding subject-extracted structures. These results contrast with results from processing other Subject-Verb-Object languages like English, in which object-extracted structures are more complex than subject-extracted structures. A key word-order difference between Chinese and other Subject-Verb-Object languages is that Chinese relative clauses precede their head nouns. Because of this word order difference, the results follow from a resource-based theory of sentence complexity, according to which there is a storage cost associated with predicting syntactic heads in order to form a grammatical sentence. The results are also consistent with a theory according to which people have less difficulty processing embedded clauses whose word order matches the word order in main clauses. Some corpus analyses of Chinese texts provide results that constrain the classes of possible frequency-based theories. Critically, these results demonstrate that there is nothing intrinsically easy about extracting from subject position: depending on the word order in the main clause and in a relative clause, extraction from object position can be easier to process in some circumstances.

The influence of referential processing on sentence complexity

This paper reports the results of five experiments designed to investigate the effects of referential processing on sentence complexity. Gibson ( Cognition, 68 (1998) 1) suggested that sentence complexity is related to the locality of integrations between dependent syntactic heads, and that an appropriate measure of locality is the number of new discourse referents intervening between the endpoints of those integrations. The experiments in this paper test, modify and extend Gibson's (1998) claims. Each experiment manipulated noun phrases (NPs) in the subject positions of object-extracted relative clauses in order to determine how different types of NPs affected sentence complexity. Experiments 1, 2 and 3 used questionnaires to gauge sentence complexity, whereas Experiments 4 and 5 used self-paced reading. The results from Experiments 1, 2, 4 and 5 suggest that the complexity of the experimental items was more closely related to the Givenness status of the embedded subject in the Givenness Hierarchy than to whether the embedded subject was old or new to the discourse. Experiment 3 compared materials in which a quantifier was rotated through subject positions of a nested relative clause structure. The results of this experiment support a discourse-processing-based distance metric for computing locality and provide evidence against a pure similarity-based account of structural complexity such as proposed by Bever (Bever, T. G. (1970). The cognitive basis of linguistic structures. In J. R. Hayes (Ed.), Cognition and the development of language (pp. 279–362). New York: Wiley).

Linguistic complexity: locality of syntactic dependencies

This paper proposes a new theory of the relationship between the sentence processing mechanism and the available computational resources. This theory – the Syntactic Prediction Locality Theory (SPLT) – has two components: an integration cost component and a component for the memory cost associated with keeping track of obligatory syntactic requirements. Memory cost is hypothesized to be quantified in terms of the number of syntactic categories that are necessary to complete the current input string as a grammatical sentence. Furthermore, in accordance with results from the working memory literature both memory cost and integration cost are hypothesized to be heavily influenced by locality (1) the longer a predicted category must be kept in memory before the prediction is satisfied, the greater is the cost for maintaining that prediction; and (2) the greater the distance between an incoming word and the most local head or dependent to which it attaches, the greater the integration cost. The SPLT is shown to explain a wide range of processing complexity phenomena not previously accounted for under a single theory, including (1) the lower complexity of subject-extracted relative clauses compared to object-extracted relative clauses, (2) numerous processing overload effects across languages, including the unacceptability of multiply center-embedded structures, (3) the lower complexity of cross-serial dependencies relative to center-embedded dependencies, (4) heaviness effects, such that sentences are easier to understand when larger phrases are placed later and (5) numerous ambiguity effects, such as those which have been argued to be evidence for the Active Filler Hypothesis.