The influence of only on syntactic processing of "long" relative clause sentences

We report an eye movement experiment investigating the influence of the focus operator only on syntactic processing of "long" relative clause sentences. Paterson, Liversedge, and Underwood (1999) found that readers were garden pathed by "short" reduced relative clause sentences containing the focus operator only . They argued that due to thematic differences between "short" and "long" relative clause sentences, garden path effect might not occur when "long" reduced relative clause sentences are read. Eye-tracking data show that garden path effects found during initial processing of the disambiguating verb of "long" reduced sentences without only were absent or delayed in the case of counterparts with only . We discuss our results in terms of current theories of sentence processing.     

Plausibility and Verb Subcategorization in Temporarily Ambiguous Sentences: Evidence from Self-Paced Reading

A self-paced reading experiment investigated processing of sentences containing a noun-phrase that could temporarily be mistaken as the direct-object argument of a verb in a subordinate clause but actually constituted the syntactic subject of the main clause (often referred to as an early vs. late closure ambiguity). Subcategorization preference of the subordinate verb and plausibility of the syntactic misanalysis were manipulated. Elevated reading times occurred during processing of the temporarily ambiguous noun-phrase for those sentences where the noun-phrase was an implausible direct-object of the preceding verb, regardless of the verbs subcategorization preferences. Elevated reading times were observed for all sentence types following syntactic disambiguation. Subsequent correlational analyses showed that the verbs individual subcategorization preferences affected processing time on the critical noun-phrase and the syntactically disambiguating main verb.     

Discourse influences during parsing are delayed.

Subjects read sentences containing either a syntactically ambiguous prepositional phrase attachment or a syntactically ambiguous reduced relative clause. The sentences were embedded in passages of text that were consistent with either the minimal or non-minimal attachment reading. In addition, a discourse factor (i.e., whether or not the target sentence was in the discourse focus) was varied. Subjects' eye movements were recorded as they read the passages of text. Our primary finding was that subjects were garden-pathed even when there was biasing context. However, when the target sentence was in the discourse focus, subjects were able to recover more readily from their initial erroneous parse of the sentence. The data thus support models of sentence parsing that postulate that the parsing of a sentence is based upon structurally based principles and the influence of semantic or pragmatic information makes itself felt only after the initial parsing decision has been made.     

Underspecification of syntactic ambiguities: Evidence from self-paced reading

Syntactically ambiguous sentences are sometimes read faster than disambiguated strings. Models of parsing have explained this tendency by appealing either to a race in the construction of alternative structures or to reanalysis. However, it is also possible that readers of ambiguous sentences save time by strategically underspecifying interpretations of ambiguous attachments. In a self-paced reading study, participants viewed sentences with relative clauses that could attach to one of two sites. Type of question was also manipulated between participants in order to test whether goals can influence reading/parsing strategies. The experiment revealed an ambiguity advantage in reading times, but only when participants expected superficial comprehension questions. When participants expected queries about relative clause interpretation, disambiguating regions were inspected with more care, and the ambiguity advantage was attenuated. However, even when participants expected relative clause queries, question-answering times suggested underspecified representations of ambiguous relative clause attachments. The results support the construal and "good-enough" models of parsing.     

Eye movements of young and older adults during reading

The eye movements of young and older adults were tracked as they read sentences varying in syntactic complexity. In Experiment 1, cleft object and object relative clause sentences were more difficult to process than cleft subject and subject relative clause sentences; however, older adults made many more regressions, resulting in increased regression path fixation times and total fixation times, than young adults while processing cleft object and object relative clause sentences. In Experiment 2, older adults experienced more difficulty than young adults while reading cleft and relative clause sentences with temporary syntactic ambiguities created by deleting the that complementizers. Regression analyses indicated that readers with smaller working memories need more regressions and longer fixation times to process cleft object and object relative clause sentences. These results suggest that age-associated declines in working memory do affect syntactic processing.     

Processing relative clauses varying on syntactic and semantic dimensions: An analysis with event-related potentials

Event-related potentials were used to study how parsing of German relative clauses is influenced by semantic information. Subjects read well-formed sentences containing either a subject or an object relative clause and answered questions concerning the thematic roles expressed in those sentences. Half of the sentences contained past participles that on grounds of semantic plausibility biased either a subject or an object relative reading; the other half contained past participles that provided no semantic information favoring either reading. The past participle elicited an N400 component, larger in amplitude for neutral than for semantically biased verbs, but this occurred only in the case of subject relative clauses. More specific effects were obtained only for a subgroup of subjects, when these were grouped into fast and slow comprehenders on the basis of their questionanswering reaction times. Fast comprehenders showed larger N400 amplitudes for neutral than for semantically biased past participles in general and larger N400s for the latter when there was a bias for an object relative reading as opposed to a subject relative reading. Syntactic ambiguity resolution, indicated by an auxiliary in sentence final position, was associated in this subgroup with a positive component (P345), larger in amplitude for auxiliaries indicating an object relative reading than for those indicating a subject relative reading. The latter component was independent of semantically biasing information given by a preceding past participle. Implications of these findings for models of language comprehension are considered.     

Effects of Local and Global Context on Processing Sentences with Subject and Object Relative Clauses

An eye tracking study investigated the effects of local and global discourse context on the processing of subject and object relative clauses, whereby the contexts favored either a subject relative clause interpretation or an object relative clause interpretation. The fixation data replicated previous studies showing that object relative clause sentences were more difficult to process than subject relative sentences. Crucially, however, the reading difficulty asymmetry between subject and object relative clause sentences disappeared when the sentences were presented with a local or a global discourse context that favored the objects in the object relative clauses. These findings demonstrate that the evidence for a syntax-based account of sentence processing is found when sentences are presented in isolation. However, if sentences are placed more naturally, in context, discourse factors outweigh the initial structural assignment.     

Effects of punctuation on the processing of temporarily ambiguous sentences in Japanese

This study explored the effects of comma insertion on the processing of garden path sentences in Japanese. In two experiments, participants read relative clause sentences containing two ambiguities: single versus relative clause and early‐opening (EO) versus late‐opening (LO) left clause boundaries. EO sentences were presented with or without a comma compatible with an EO boundary in Experiment 1 and, in Experiment 2, with an LO boundary. The results showed that the comma, whether compatible or incompatible with the correct clause boundary, decreased reading time for the relative clause's head noun, indicating that a comma helps readers avoid or recover from garden paths caused by relative clause structures. Conversely, a comma incompatible with a clause boundary increased processing costs of second ambiguity resolution (EO vs. LO). We concluded that punctuation affects processing of temporary ambiguity in Japanese as in languages with stricter punctuation rules; furthermore, readers depend strongly on punctuation for online processing of whole sentence structures. We also discuss the relationship between punctuation and (implicit) prosody.     

The on-line resolution of the sentence complement/relative clause ambiguity: evidence from Spanish

Two self-paced reading experiments investigated syntactic ambiguity resolution in Spanish. The experiments examined the way in which Spanish subjects initially interpret sentences that are temporarily ambiguous between a sentence complement and a relative clause interpretation. Experiment 1 examined whether the sentence complement preference found in English is observed in Spanish speaking subjects. In Experiment 2, verbal mood was manipulated in order to study the influence of verb-specific information on sentence processing. Since subcategorization for a subjunctive complement clause is generally assumed to be a lexical property of some verbs, the manipulation of the mood of the embedded verb affords us an interesting and novel way to examine the influence of lexical information on syntactic ambiguity resolution. Experiment 1 showed that Spanish speakers initially interpret the ambiguous that-clause as a sentence complement. Experiment 2 showed that verb-specific information, in particular, the information that specificies that a verb subcategorizes for a subjunctive complement, is accessed and used rapidly and affects the ambiguity resolution process. The results are discussed in relation to current models of sentence processing.     

The subordination effect: Evidence from self-paced reading and recall

Engelkamp and Rummer (2002) demonstrated that auditorily presented subordinate causal sentences are better retained than coordinate sentences. This subordination effect was explained by suggesting that subordinate sentences are merged more easily in memory than coordinate sentences. The present paper enlarges Engelkamp and Rummer's findings with respect to three aspects. First, it demonstrates that the subordination effect can only be found if a verbatim but not a content related recall score is used. Second, using self-paced reading, it demonstrates a processing advantage for subordinate sentences. This reading time advantage was only observed if the subordinate clause preceded the matrix clause. Third, it excludes an alternative explanation of the subordination effect which attributes memory differences to the fact that the critical causal conjunction word was presented earlier in subordinate than in coordinate sentences. In sum, our findings suggest a direct contribution of syntactic information to sentence regeneration.     

Syntactic priming in Chinese sentence comprehension: Evidence from Event-Related Potentials

Using the event-related potential (ERP) technique, this study examined the nature of syntactic priming effects in Chinese. Participants were required to read prime-target sentence pairs each embedding an ambiguous relative clause (RC) containing either the same verb or a synonymous verb. In Chinese, the word de serves as a relative clause marker. During reading a potential Chinese RC structure (either the prime or the target sentence), Chinese readers initially expect to read an Subject–Verb–Object (SVO) structure but the encounter of a relative clause marker de would make readers abandon the initial strategy and reanalyze the structure as a relative clause. A reduced P600 effect was elicited by the critical word de in the target sentence containing the same initial verb as in the prime sentence. No significant reduction of the P600 was observed in the target sentences in the synonymous condition. The results demonstrated that verb repetition but not similarity in meaning produced a syntactic priming effect in Chinese. The constraint-based lexicalist hypothesis and the argument structure theory were adopted to explain the syntactic priming effect obtained in the current study.     

Recall of grammatical relations within clause-containing sentences

Two major findings were obtained in a study of college students' recall of meaningful grammatical relations within sentences: (1) verb-object relations in object focus relative clauses were recalled less accurately than verb-object relations in subject focus relative clauses, thus supporting the hypothesis that permuted word order in certain relative clauses interferes with adequate encoding of underlying grammatical relations, and (2) subject-verb relations in nested sentences in which a relative clause intervened between subject and verb (nested sentences) were retained in memory as accurately as uninterrupted subject-verb relations (not nested sentences).     

An on-line assessment of causal reasoning during comprehension

Fletcher and Bloom (1988) have argued that as readers read narratives, clause by clause, they repeatedly focus their attention on the last preceding clause that contains antecedents but no consequences in the text. This strategy allows them to discover a causal path linking the text's opening to its final outcome while minimizing the number of times long-term memory must be searched for missing antecedents or consequences. In order to test this hypothesis, we examined the reading times of 25 subjects for each clause of eight simple narrative texts. The results show that: (1) causal links between clauses that co-occur in short-term memory (as predicted by the strategy) increase the time required to read the second clause; (2) potential causal links between clauses that never co-occur in short-term memory (again as predicted by the strategy) have no effect on reading time; and (3) reinstatement searches are initiated at the end of sentences that are causally unrelated to the contents of short-term memory or that contain clauses that satisfy goals no longer in short-term memory. These results support the claim that subjects engage in a form of causal reasoning when they read simple narrative texts.     

Sentence processing strategies in Spanish and English

In parallel experiments, 12 English- and 12 Spanish-speaking subjects read right-branching and self-embedded sentences with one, two, or three subordinate clauses, in their native languages. Subjects read the sentences one word at a time, the subjects controlling the rate of presentation by means of a computer keyboard. The reading time for each word was recorded. After each sentence subjects performed one of four comprehension tasks. Reading times indicated that Spanish- and English-speaking subjects employ different processing strategies. Results of the comprehension tasks indicated that Spanish-but not English-speaking subjects understood self-embedded sentences with two subordinate clauses. These results are discussed in terms of the relative importance of the clause as a perceptual unit in the two languages, and the implications of the differences in comprehension for theories of sentence processing.     

Evaluating information for truthfulness: The effects of logical subordination

Research has shown that many individuals do not routinely evaluate new information for consistency with respect to what they already know. One factor that may affect the likelihood of critical evaluation is whether or not the information is the central focus of the message. Two experiments tested this possibility by establishing differential emphasis of false information within complex sentences. Half of the target sentences contained a false fact in the main clause and half contained a false fact in the subordinate clause. In Experiment 1 subjects verified 64 sentences presented orally as either true or false. In Experiment 2 subjects read and evaluated 20 paragraphs for the presence of false information. As expected, subjects were less likely to report the false information when it was conveyed as logically subordinate rather than central. The results suggest one explanation for deficits in comprehension monitoring and have implications for understanding susceptibility to persuasive communications.     

The effect of noun phrase type on working memory saturation during sentence comprehension

Double centre-embedded structures such as “the rat the cat the boy chased ate was brown” seem ungrammatical to many human subjects. Using an offline complexity judgement task, Gibson and Thomas (1999) demonstrated that people found such sentences no more difficult to understand when the second verb phrase (VP) was omitted, relative to a condition where all the required VPs were present. According to the Syntactic Prediction Locality Theory (SPLT; Gibson, 1998), this syntactic illusion is determined by the high working memory cost associated with the integration of the second VP. This cost could be reduced by replacing the third noun phrase (the boy) by a pronoun, making the reader more sensitive to the omission of the second VP. This hypothesis was tested in two experiments using French sentences. Both experiments confirmed the syntactic illusion when the second VP was not a pronoun. The second experiment measured the reading times of the VPs and showed that the pronoun induced a longer reading time of the final VP when the second VP was omitted. The overall results indicate a condition under which human subjects could process the most complex part of a sentence with more than one embedded relative clause. The overall results are consistent with most of the hypotheses derived from the SPLT although offline complexity judgements could not be the most sensitive measure to test some of these hypotheses.     

Active memory processes in visual sentence comprehension: Clause effects and pronominal reference

Two experiments were conducted to investigate active memory processes during reading. Subjects read two-clause sentences one word at a time at a self-paced rate. Following each sentence a probe word was presented; subjects were to decide if this word occurred in the sentence they had just read. The first experiment examined clausal effects during reading. Reaction times to items from the final clause were shorter than those to items from a previous clause even when the same number of words intervened. The second experiment used the clause effect to address the issue of proniminal reference. Results indicated that a pronoun in the final clause activated the meaning of its antecedent, thus demonstrating that the method is sensitive to both surface and meaning codes in active memory.     

Syntactic structure and the garden path

The experiment investigated locally ambiguous English sentences containing “complement” verbs such as believe, which can be followed either by a direct object or by a complement clause. These two sentence types were compared with unambiguous sentences in which the complement clause was introduced by the word that. Subjects processed numerous examples of these sentences in a word-by-word self-paced reading task. At the disambiguation point after the ambiguous noun phrase, longer reading times were obtained for reduced complement constructions compared with direct object sentences. Such an effect has been attributed to the operation of the parsing principle Minimal Attachment (Frazier and Rayner, 1982). This principle predicts that subjects assume falsely that the noun phrase after the complement verb in the reduced complement constructions is the direct object, resulting in the need for subsequent structural reanalysis. However, longer times in the disambiguating zone were also found for the unambiguous that complements. Thus, the complexity difference seems not to represent “garden-pathing” as a result of the operation of Minimal Attachment, but may instead reflect the extra complexity caused by having to handle two sets of clausal relations instead of just one.     

Effects of Irrelevant Sounds on Phonological Coding in Reading Comprehension and Short term Memory

The effects of irrelevant sounds on reading comprehension and short-term memory were studied in two experiments. In Experiment 1, adults judged the acceptability of written sentences during irrelevent speech, accompanied and unaccompanied singing, instrumental music, and in silence. Sentences varied in syntactic complexity: Simple sentences contained a right-branching relative clause ( The applause pleased the woman that gave the speech ) and syntactically complex sentences included a centre-embedded relative clause ( The hay that the farmer stored fed the hungry animals ). Unacceptable sentences either sounded acceptable ( The dog chased the cat that eight up all his food ) or did not ( The man praised the child that sight up his spinach ). Decision accuracy was impaired by syntactic complexity but not by irrelevant sounds. Phonological coding was indicated by increased errors on unacceptable sentences that sounded correct. These error rates were unaffected by irrelevant sounds. Experiment 2 examined effects of irrelevant sounds on ordered recall of phonologically similar and dissimilar word lists. Phonological similarity impaired recall. Irrelevant speech reduced recall but did not interact with phonological similarity. The results of these experiments question assumptions about the relationship between speech input and phonological coding in reading and the short-term store.     

Processing Italian Relative Clauses: Working Memory Span and Word Order Effects on RTs

In this study, the authors aim to clarify whether the subject–object asymmetry in relative clause comprehension is due to the use of parsing strategies (Active Filler Theory) or to a greater memory load generated by object sentences. Two experiments investigate how individual differences in working memory span may influence the reading times of relative sentences in Italian, a language characterized by a flexible structure. The results of Experiment 1 indicate that object extraction is more complex than subject extraction when sentences have a canonical structure. Furthermore, low-span participants have particular difficulties with object relative sentence comprehension. The results of Experiment 2 show that subject-relative clauses with uncanonical structures are more complex to understand than object-relative clauses, and low-span participants have more difficulties than high-span participants in elaborating both subject and object relative clauses. These data seem to be coherent with the Active Filler Theory.