Immediate memory for words from main and subordinate clauses at different age levels

A probe-latency task was used to assess accessibility to the words from the first and second clauses of four types of sentences. The sentences contained either independent clauses or main and subordinate clauses. The subjects were 3-, 4-, and 5-year-old children, and adults. On sentences with no main-subordinate distinction, word recognition latencies were shorter for second clauses for all groups except 4-year-olds. On sentences with main and subordinate clauses systematically varied over position in the sentence, however, latencies were most often shorter for subordinate clauses, even when they occurred at the beginning of the sentence. The results indicate that a clause is not simply represented in abstract form rather than verbatim form once the complete clause has been heard, but instead the structural role of the clause, as well as other factors, influences accessibility to verbatim form. It is proposed that listeners frequently interpret an asserted main clause more readily than a subordinate clause. This comprehension strategy appears in different forms at different stages of development.This research was supported in part by NIMH Fellowship No. 1 FO2MH 57352-01 and in part by a Montclair State College Faculty Research Grant to the first author.     

Clause structure of sentences and speech processing

Listeners heard narrative stories in segments 20-60 sec long, and wrote their immediate recall for the most recent speech in each segment. Segments ended in four ways: there was a main clause alone, a subordinate clause alone, a main clause preceding a subordinate clause, or a subordinate clause preceding a main clause. Only these final sentences were well recalled. Of these, single-clause sentences were recalled best and two-clause sentences with main-subordinate clause order were recalled worst. An interaction obtained between clause position and function suggests that processing may be delayed when sentences fall to begin with main clauses.     

Discourse structure and relative clause processing

Studies in several languages have shown that subject-relative clauses are easier to process than object-relative clauses. Mak, Vonk, and Schriefers (2006) have proposed the topichood hypothesis to account for the preference for subject-relative clauses. This hypothesis claims that the entity in the relative clause that is most topicworthy will be chosen as the subject. By default, the antecedent of the relative clause will be chosen as the subject of the relative clause, because it is the topic of the relative clause. However, when the noun phrase (NP) in the relative clause is also topicworthy, the preference for the antecedent to be the subject will disappear. This was confirmed in two experiments. In Experiment 1, we tested relative clauses with a personal pronoun in the relative clause. We obtained a preference for object-relative clauses, in line with the assumption that personal pronouns refer to a discourse topic and are thus topicworthy. In Experiment 2, the discourse status of the NP in the relative clause was manipulated; either it was not present in the preceding context, or it was the discourse topic. The experiment showed that when the NP in the relative clause refers to the discourse topic, the difficulty of object-relative clauses is reduced, in comparison with relative clauses with an NP that is new in the discourse, even in the absence of any explicit cue in the relative clause itself. The experiments show that discourse factors guide processing at the sentence level.     

Processing controlled PROs in Spanish

Two experiments were carried out to investigate the processing of the empty category PRO and the time-course of this in Spanish. Eye movements were recorded while participants read sentences in which a matrix clause was followed by a subordinate infinitival clause, so that the subject or the object of the main clause could act as controller of PRO, and therefore as implicit grammatical subject of the infinitive. In Experiment 1, verb control information was manipulated: The matrix clause contained either subject-control verbs like prometer ('promise') or object-control verbs like forzar ('force'). In Experiment 2, the preposition that headed adverbial subordinate clauses was manipulated: Two different kinds of infinitival adverbial clauses were used, expressing purpose (preposition para) and reason (preposition por) and in which control information is primarily induced by the prepositions (para tends to trigger subject-control; por object-control). Experiment 1 showed that readers make immediate use of verb control information to recover the antecedent of the empty category PRO in Spanish obligatory control constructions. The data obtained in Experiment 2 suggest that during the processing of the empty category PRO in purpose vs. reason adverbial subordinate infinitival clauses the control information induced by the prepositions por vs. para is not initially used as a constraint to guide the selection of the nominal antecedent of PRO. In addition, both experiments showed that PRO antecedent selection is a very fast process and that, together with verb control information, recency played an important role. The results are discussed in terms of current psycholinguistic hypotheses about empty categories and in relation to formal linguistic hypotheses about PRO control. We argue that obligatory control ties (which are co-referential ties) are processed fast because they are launched from the same lexical platform that launches all fast syntactic connections (complements, as opposed to modifiers). In short, that such lexically-specified co-referential ties are regulated by linguistic form.     

Planning units and syntax in sentence production

The study was conducted to determine, first, whether it is the deep or the surface clause that is more important as a speech planning unit, and second, whether syntactic decisions are made during sentence production. Subjects, while talking, heard tones to which they had to respond by pressing a button; reaction times to these tones were taken as an index of processing load during production. It was found that there were increased RTs at the ends compared with the beginnings of deep structure clauses. No difference was found between RTs at the beginnings and ends of surface clauses not corresponding to a deep clause. The results were interpreted as showing that deep clauses are major planning units and that some planning for clauses occurs at the end of the preceding clause. Differences were found between RTs during clauses of different syntactic structure. These results were interpreted as indicating that syntax influences production and were discussed in relation to previous studies of pausing and speech disruption.     

Event order versus syntactic structure in recall of adverbial complex sentences

Two experiments using recall of sentences examined two contrasting principles of clause ordering in a type of complex sentences: the main-clause-first (syntactic) principle and the event-order (or temporal-causal order) prir ciple. In Experiment 1, these two principles were studied in complex sentences with a main clause and a subordinate adverbial clause-e.g., When she heard the thunder, she stopped playing Frisbee. In sentences of this type the subordinate clause typically describes a temporally or causally antecedent event, while the main clause describes a subsequent event in the temporal-causal sequence. These two principles make opposite predictions on what is the psychologically simpler or preferred order of the two clauses in this type of complex sentence. Results of Experiment 1 showed an overall preference in memory for main-clause-first order. In Experiment 2, complex sentences with a main clause and a subordinate clause not temporally or causally related were also used in a sentence recall task. Similar results were obtained. The implication of these findings for the determinants of linguistic structures was discussed.     

Temporal references and temporal relations in sentence comprehension

The author investigated the interpretation of temporal references during comprehension of sentences containing a main and subordinate clause. Experiments 1 and 2 examined state and event subordinate clauses, respectively, and showed that subordinate temporal references overlapping with or close to the time of the main clause event were read faster than nonoverlapping distant references. Experiment 3 examined temporal references in nonsubordinate main clauses and confirmed that temporal relations between main and subordinate clauses were established on-line in the previous experiments. Experiment 4 independently manipulated temporal overlap and distance and suggested that event and state clauses are processed according to distinct temporal parameters. The results are explained by the contingency relations that events and states establish with other discourse events.     

The role of pragmatic principles in resolving attachment ambiguities: Evidence from eye movements

In an eyetracking experiment, participants read sentences that contained a prepositional phrase (PP) that could be attached to one of two preceding verbs. To understand the sentence, readers had to select which verb would serve as the host for the PP. In some of the sentences, the critical verbs and the PPs were part of a subordinate clause in which lexical and syntactic factors were expected to matter, but discourse factors favoring attachment of the material to positions where it would be relevant to the main assertion of the sentence were not expected to matter. In other sentences, the critical material was tested in main clause contexts in which the main assertion principle was predicted to apply. Hierarchical linear modeling showed that online attachment preferences were affected by clause type (main vs. subordinate). Specifically, the preference for a local verb over a distant verb was greater when the critical material appeared within a subordinate clause than when it appeared within a main clause. This pattern of results can be explained by the operation of the relativized relevance or main assertion principle, which in our sentences meant that participants favored attachment of the PP to the first verb over the second.     

Neural correlates of Dutch Verb Second in speech production

Dutch speakers with agrammatic Broca's aphasia are known to have problems with the production of finite verbs in main clauses. This performance pattern has been accounted for in terms of the specific syntactic complexity of the Dutch main clause structure, which requires an extra syntactic operation (Verb Second), relative to the basic Subject-Object-Verb order surfacing in Dutch subordinate clauses. We report an fMRI study into the question whether this syntactic complexity is reflected in increased brain activation correlated with the production of Dutch main clause word order, in speakers without language impairment. Nineteen healthy subjects performed a covert sentence completion task, during which main and subordinate clauses were alternately elicited in a block design. Results show a left middle to superior frontal cluster of activation correlated to production of Verb-Second over Verb-Final clauses, with no activation in the opposite contrast. This activation pattern is counter to what might be expected from the frequency distribution of main and subordinate clauses. We conclude that the Verb-Second deviation from the basic Dutch SOV word order costs extra neural resources and that this also underlies the agrammatic problems with the production of finite verbs in Dutch main clauses.     

When is cataphoric reference recognised?

Pronouns typically have explicit antecedents in the prior discourse otherwise processing difficulty is experienced. However, it has been argued [Gordon, P. C., & Hendrick, R. (1997). Intuitive knowledge of linguistic co-reference. Cognition, 62, 325–370; Gordon, P. C., & Hendrick, R. (1998). The representation and processing of co-reference in discourse. Cognitive Science, 22, 389–424] that when a pronoun appears in a preposed subordinate clause (as in, Before she began to sing, Susan stood up), incremental interpretation is suspended and no antecedent is immediately sought, since the pronoun cannot be resolved until the main clause is encountered. We report results from an eye-tracking study showing that on encountering a pronoun that has no prior antecedent (compared to cases where there is an explicit prior antecedent), readers experience immediate difficulty whether or not the pronoun appears in a preposed subordinate clause, suggesting that attempted incremental interpretation is not suspended in these cases.     

Working memory contributions to relative clause attachment processing: A hierarchical linear modeling analysis

An eye-movement-monitoring experiment tested readers' responses to sentences containing relative clauses that could be attached to one or both of two preceding nouns. Previous experiments with such sentences have indicated that globally ambiguous relative clauses are processed more quickly than are determinately attached relative clauses. Central to the present research, a recent study (Swets, Desmet, Hambrick, & Ferreira, 2007) showed that offline preferences for such sentences differ as a function of working memory capacity. Specifically, both English and Dutch participants' preference for the second of two nouns as the host for the relative clause increased as their working memory capacity increased. In the present study, readers' working memory capacity was measured, and eye movements were monitored. Hierarchical linear modeling was used to determine whether working memory capacity moderated readers' online processing performance. The modeling indicated that determinately attached sentences were harder to process than globally ambiguous sentences, that working memory did not affect processing of the relative clause itself, but that working memory did moderate how easy it was to integrate the relative clause with the preceding sentence context. Specifically, in contrast with the offline results from Swets and colleagues' study, readers with higher working memory capacity were more likely to prefer the first noun over the second noun as the host for the relative clause.     

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.     

Does Structural Complexity Necessarily Imply Processing Difficulty?

Our goal is to establish a link between the time needed to plan a sentence containing an embedded clause and the structure of this sentence. Contrary to a traditional monolithic conception of subordination, three types of embeddings were considered, depending on their degree of syntactic integration: subcategorized, modifier and pseudo-embedded clauses. We hypothesized that in the case of subcategorization, fewer pauses should occur between the matrix and the subordinate clause since the latter is required by the lexical properties of verbs. By contrast, pseudo-embedded clauses are the less integrated. Hence, they should exhibit planning characteristics similar to the ones of simple sentences, the matrix clause and the subordinate clauses being planned in two steps. Twenty texts produced by French speaking adults were recorded. Pauses were characterized according to their duration and position. Globally, both predictions were confirmed. We conclude that supposedly complex sentences are not necessarily difficult to process.     

On-line and off-line reflexive resolution in Japanese logophoric sentences

This study investigates on-line and off-line resolution of a Japanese reflexive,jibun, for logophoric sentences, i.e., complex sentences involving a matrix verb that reflects one's point of view feelings, or state of consciousness, and for nonlogophoric sentences, i.e., complex sentences involving a subordinate adverbial clause. According to Kuroda's (1973) thesis and Chomsky's (1981) binding principle (for nonlogophoric sentences only), the reflexive in the logophoric sentences can be associated with the subject of both a matrix sentence and a subordinate sentence whereas that in the nonlogophoric sentences can only be associated with the subject of the subordinate sentence. In Experiment 1, 42 students were administered a probe-recognition task in which a probe was given for the subject either of the matrix sentence or of the subordinate sentence immediately after the end of the subordinate clause or at the end of a sentence following the matrix verb. Recognition times were faster for a matrix-subject probe than for a subordinatesubject probe regardless of the sentence type and probe position. In Experiment 2, 40 students were administered an on-line antecedent identification task in which they were required to quickly and accurately identify, when given a probe, the antecedent of the reflexive, with the probe given after the reflexive or at the end of a sentence. Regardless of the sentence type, matrix-subject was judged to be the antecedent of the reflexive more often than subordinate-subject, with the effect of probe position being negligible. An offline study required 136 students to indicate the antecedent(s) for the two types of sentence given in their entirety. No effect of sentence type was found. Findings indicate that neither Kuroda's thesis nor Chomsky's binding principle is applied when Japanese speakers parse logophoric and nonlogophoric sentences.Part of this study was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture, No. 05610067. Deep gratitude is due to Professor D. D. Steinberg for reading an earlier version of this paper. Thanks are also due to Ms. S. Ogawa for her help in collecting part of the off-line data.     

A note on temporal relations between language and gestures

The initiation of the spontaneous gestures of Wernicke's aphasics was analyzed in relation to shifts in semantic content between the syntactic boundaries of main clauses and embedded clauses. Gestures proved more likely to arise at the initial boundaries of embedded clauses when these were semantically discontinuous with the main clause than when these were semantically related to the main clause. Spontaneous gestures may signal underlying shifts in semantic intention, thereby reflecting the difficulties encountered by Wernicke's aphasics in maintaining a coherent stream of thought across syntactic boundaries.     

The On-Line Processing of Verb-Phrase Ellipsis in Aphasia

We investigate the on-line processing of verb-phrase ellipsis (VPE) constructions in two brain injured populations: Broca’s and Anomic aphasics. VPE constructions are built from two simple clauses; the first is the antecedent clause and the second is the ellipsis clause. The ellipsis clause is missing its verb and object (i.e., its verb phrase (VP)), which receives its reference from the fully specified VP in the antecedent clause. VPE constructions are unlike other sentence types that require displacement of an argument NP; these latter constructions (e.g., object-relatives, wh-questions) yield either on-time or delayed antecedent reactivation. Our results demonstrate that Anomics, like unimpaired individuals, evince reactivation of the direct object NP (within the VP) at the elided position. Broca’s patients, on the other hand, do not show reactivation of the antecedent. We consider several interpretations for our data, including explanations focusing on the larger ‘grain size’ of the reconstructed material in the ellipsis clause, the properties of the auxiliary that carries tense and agreement features, and the possibility that the cost-free syntactic copy procedure claimed to underlie VPE may be modulated by the functional deficit in Broca’s aphasia.     

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.     

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.     

The effect of clause wrap-up on eye movements during reading

The effect of clause wrap-up on eye movements in reading was examined. Readers read passages in which a target category noun referred to either a high typical or a low typical antecedent. In addition, the category noun was either clause final or non-clause final. There were four primary results: (1) Readers looked longer at a category noun when its antecedent was a low typical member of the category than when it was a high typical member; (2)readers looked longer at the category noun and at the post-category region when they were clause final than when they were not clause final; (3) readers regressed from a category noun or post-category region more frequently when it was clause final than when it was not clause final; and (4) readers made longer initial saccades when their eyes left the category noun or post-category region when this word was in clause final position than when it was not clause final. The last result suggests that sometimes higher order processes that are related to making a decision about when to move the eyes impinge on lower level decisions that are typically associated with deciding where to move the eyes.