Hyper - Active Gap Filling 1 RUNNING HEAD : Hyper - Active Gap Filling Hyper - Active Gap Filling : Pre - verbal Object Gap Creation in English Filler - Gap Dependency Processing

Much work has demonstrated that speakers of verb-final languages are able to construct rich syntactic representations in advance of verb information. This may reflect general architectural properties of the language processor, or it may only reflect a language-specific adaptation to the demands of verb-finality. The present study addresses this issue by examining whether speakers of a verb-medial language (English) wait to consult verb information before constructing fillergap dependencies, where internal arguments are fronted and hence precede the verb. This configuration makes it possible to investigate whether the parser actively makes representational commitments on the gap position before verb information becomes available. A key prediction of the view that rich pre-verbal structure-building is a general architectural property is that speakers of verb-medial languages should predictively construct dependencies in advance of verb information, and therefore that disruption should be observed when the verb has properties that are incompatible with the predicted structure. In three reading experiments (self-paced and eye-tracking) that manipulated verb transitivity we found evidence for reading disruption when the verb was intransitive, although no such reading difficulty was observed when the critical verb was embedded inside a syntactic island structure, in which filler-gap dependency completion is blocked by linguistic constraints. These results are consistent with the hypothesis that in English, as in verb-final languages, information from preverbal NPs is sufficient to trigger active gap creation without having access to verb transitivity information. Hyper-Active Gap Filling 4 HYPER-ACTIVE GAP FILLING: PRE-VERBAL OBJECT GAP CREATION IN ENGLISH FILLER-GAP DEPENDENCY PROCESSING A leading goal of sentence processing research is to understand how the parser adapts to a multitude of linguistic differences across languages to enable successful comprehension. In this regard, comparisons of verb-medial and verb-final languages have provided a valuable source of evidence (Inoue & Fodor, 1995; Mazuka & Lust, 1990). The head of a verb phrase (VP) contains rich information such as subcategorization and thematic role information that is critical for constructing structural analyses and interpretations of the phrase (e.g., Chomsky, 1965; Grimshaw, 1990; Pollard & Sag, 1994), and much experimental evidence shows that the verb is a valuable source of information for parsing (e.g., Blodgett & Boland, 2004; Boland, Tanenhaus, & Garnsey, 1990; Ford, Bresnan, & Kaplan, 1982; Garnsey, Pearlmutter, Myers, & Lotocky, 1997; Mauner & Koenig, 2000; MacDonald, Pearlmutter, & Seidenberg, 1994; Snedeker & Trueswell, 2004; Spivey-Knowlton & Sedivy, 1995; Tanenhaus & Carlson, 1989; Traxler, Pickering, & McElree, 2002). The importance of the information from the verb head has engendered theoretical claims that structure building processes do not even start until the parser encounters the head of a structural unit to be constructed, even in verb-final languages where this would be significantly delayed (Pritchett, 1992; Abney, 1989). However, subsequent empirical research on verb-final languages like Japanese or German has generated strong evidence against such head-driven parsing theories in their strongest form, demonstrating that the parser uses various morphological and syntactic cues to incrementally build structures and interpretations in verb-final languages (Bader & Lasser, 1994; Kamide, Altmann, & Haywood, 2003; Kamide & Mitchell, 1999; Koh, 1997; Konieczny, 2000; Yoshida, 2006; Aoshima, Yoshida, and Phillips, 2009; Bornkessel, Schlesewsky, & Friederici, Hyper-Active Gap Filling 5 2002). Thus, although verb information strongly influences parsing decisions when available, speakers of verb-final languages often begin building syntactic and semantic structure in advance of the verb. These findings raise the question of whether pre-verbal structure building reflects a language-specific adaptation to the processing demands of verb-finality, or rather a property of a general parsing architecture that speakers of all languages use. For example, consider less frequent cases in verb-medial languages where multiple arguments precede the verb. A classic example of this comes from processing of ‘filler-gap’ dependencies as illustrated by the relative clause construction shown in (1), where the object noun phrase (NP) the city (called the filler) is dislocated from the post-verbal thematic position (called the gap), and the parser needs to associate the filler and the gap in order to assign a thematic interpretation. (1) The city that the author visited ____ was named for an explorer. It has been reported that speakers of verb-final languages complete filler-gap dependencies in advance of verb information, associating the filler with the earliest structural position where a thematic role could be assigned (Aoshima, Phillips, & Weinberg, 2004; Nakano, Felser, & Clahsen, 2002). The current study examines whether this may also be the case in a verb-medial language like English. If positing a gap in advance of the verb is a language-general parsing procedure rather than an adaptation specific to verb-final languages, then we predict that English speakers should posit a gap irrespective of whether the verb ultimately licenses a direct object 1 In this paper we use the ‘gap-filling’ terminology in a theory-neutral way, as is typical in the psycholinguistic literature. This terminology should not be taken as indicating a commitment to representations that include gaps or traces; all of the processing theories we discuss here could be specified in terms of representations that do not include empty categories. Hyper-Active Gap Filling 6 gap position, and that signs of reading disruption should be observed in cases where the verb does not accommodate a direct object. We report the results of three on-line reading experiments in English that tested this prediction by examining the effect of verb transitivity on reading times in filler-gap configurations. The results are consistent with the hypothesis that the parser creates the object gap in advance of the verb in English, specifically as soon as a VP constituent can be anticipated based on the presence of the filler and the subject NP, as well as grammatical knowledge that a VP can potentially contain an object NP position. These results suggest that the filler-gap dependency completion procedure may be uniform across languages, regardless of differences in verb positions. We argue that this finding is consistent with the view that the parser predictively constructs rich representations at the earliest possible moment in advance of critical bottom-up evidence. Background on Active Filler-Gap Dependency Processing Past research on filler-gap dependency processing has established that the parser postulates a gap before there is sufficient bottom-up evidence to confirm that analysis (Active gap filling: Fodor, 1978; Crain & Fodor, 1985; Stowe, 1986; Frazier & Flores D’Arcais, 1989). For example, Stowe (1986) observed the so-called Filled gap effect in (2), i.e., slower reading times at the direct object position us in the wh-fronting condition (2a) than in a control condition that did not involve wh-fronting (2b). This pattern of reading times suggests that the parser had already posited a gap following the transitive verb, before checking whether the direct object position was occupied. Hyper-Active Gap Filling 7 (2) a. My brother wanted to know who Ruth will bring us home to ____ at Christmas. b. My brother wanted to know if Ruth will bring us home to Mom at Christmas. Converging evidence comes from an eye-tracking experiment by Traxler and Pickering (1996), who manipulated the thematic fit between the filler and the potential verb host, as in (3). (3) We like the city / book that the author wrote unceasingly and with great dedication about _____ while waiting for a contract. Traxler and Pickering found a plausibility mismatch effect at the critical verb in (3), i.e., the first fixation time at the optionally transitive verb wrote increased when the filler was an implausible object of the verb (i.e., the city), compared to when the filler was a plausible object of the verb (i.e., the book). This suggests that at least as early as the verb position, the parser postulates a gap and analyzes the filler as the object of the verb. In fact, there is ample time course evidence for active object gap creation in many languages, using a variety of dependent measures such as reading time and gaze duration measures (Crain & Fodor, 1985; de Vincenzi, 1991; Frazier, 1987; Frazier & Clifton, 1989; Phillips, 2006; Pickering & Traxler, 2001, 2003; Wagers & Phillips, 2009), cross-modal priming (Nicol, 1993; Nicol & Swinney, 1989), visual world eyetracking (Sussman & Sedivy, 2003) as well as event-related potentials (Featherston, Gross, Münte, & Clahsen, 2000; Felser, Münte, & Clahsen, 2003; Garnsey, Tanenhaus, & Chapman, 1989; Gouvea, Phillips, Kazanina, & Poeppel, 2010; Kaan, Harris, Gibson, & Holcomb, 2000; Phillips, Kazanina, & Abada, 2005). The work summarized above may suggest that filler-gap dependency completion is Hyper-Active Gap Filling 8 triggered only after the parser gains access to the verb and confirms the transitivity and thematic properties of the verb. However, research on subject gap creation in English as well as studies that investigated object gap creation in verb-final languages have presented evidence that active gap creation does not depend on verb information. For example, Lee (2004) used sentences like (4) to reveal a filled gap effect in the subject NP position. (4) a. That is the laboratory which, on two different occasions, Irene used a courier to deliver the samples to ___. b. That is the laboratory to which, on two different occasions, Irene used a courier to deliver the samples ___. Here, the content of the wh-filler is manipulated in such a way that the wh-filler can plausibly be a subject (4a) or not (4b). The results showed a longer reading time at the subject NP Irene in (4a) than in (4b), suggesting that the parser had postulated a subject gap before encountering the actual subject NP. Although this interpretation has been challenged (Staub, 2010), it would in any case not be surprising that the parser actively creates a subject gap without having access to verb information, given that a subject is present in any sentence, regardless of verb properties. In this sense, if verb information were to play a role in the parser’s attempt to create a gap, the critical empirical evidence should come from object gap creation, where the presence or absence of an object gap position relies on properties of the verb. Evidence for pre-verbal object gap creation has been reported for verb-final languages like Japanese in which the object gap position linearly precedes the verb. For example, Aoshima and colleagues examined processing of long-distance scrambling sentences in which an Hyper-Active Gap Filling 9 embedded dative object NP was dislocated to sentence initial position, and found a filled gap effect at a pre-verbal dative object position (Aoshima et al., 2004). Using similar sentences, Nakano and colleagues reported evidence for an antecedent priming effect for the scrambled NP at a pre-verbal gap position (Nakano et al, 2002). These data indicate that the parser can in principle complete filler-gap dependencies before accessing verb information. In verb-medial languages, no such evidence for pre-verbal object gap creation has been reported to date. This may reflect a real difference between languages in processing strategy, and pre-verbal object gap creation in verb-final languages may reflect the parser’s adaptation to the demands of processing these languages. Maintaining the filler in memory while it is structurally unintegrated or when it has not received a thematic interpretation has been argued to impose a burden on working memory (Gibson, 1998; Gordon, Hendrick, & Levine, 2002, Haarmann & Cameron, 2005; King & Just, 1991). Alternatively, the parser may be architecturally constrained to assign a thematic interpretation to the filler as soon as possible (Aoshima, Phillips, & Weinberg, 2004; Pickering & Barry, 1991). On this view, the parser should prioritize integrating the filler into the first grammatically permissible structural position that can potentially receive a thematic role. Given that filler-gap dependencies are potentially unbounded, waiting for the verb before constructing the ultimate object gap position could impose a large processing burden on speakers of verb-final languages. In verb-medial languages like English, verbs become available relatively earlier in the sentence, such that the average working memory cost of waiting for the verb would be less than in verb-final languages. The advantage of waiting for the verb information is that the parser can reduce the likelihood of making risky commitments, because the verb may turn out to be intransitive and disallow an object NP analysis for the filler. In English, therefore, the parser may Hyper-Active Gap Filling 10 create an object gap position only after the verb is confirmed to be transitive. This still constitutes active gap filling, in the respect that the ultimate gap position may turn out to be somewhere later than the object position in the sentence (as in the sentences that are used to illustrate filled gap effect in (2)). Let us call this a conservative active gap filling mechanism, since the bottom-up information from the verb still plays a critical role in the parser’s decision on whether to postulate an object gap or not. This view of active gap filling is rather standard for explaining filler-gap dependency completion in verb medial languages like English. For example, McElree and colleagues have argued that the dependency completion process is triggered when the parser accesses information from the verb and initiates the retrieval process for the filler that is stored in working memory (McElree & Griffith, 1998; McElree, Foraker, & Dyer, 2003; see also Lewis & Vasishth, 2005; Pickering & Barry, 1991). On the other hand, pre-verbal object gap creation in verb-final languages may reflect a language-general property of the processing architecture, although evidence for such mechanisms may be simply more difficult to obtain in verb-medial languages. In the English filler-gap case, for example, in any parser that adopts some form of left-corner strategy, the presence of the subject NP allows the parser to predict the presence of a VP (Abney & Johnson, 1991; Crocker, 1996; Gibson, 1991; Kimball, 1975; Resnik, 1992; Shieber & Johnson, 1993, Stabler, 1994). Given that a VP can contain an object NP position, the parser could project a VP with an object NP slot and assign the filler to this object position before confirming whether the upcoming verb is a transitive verb or not. Let us call this a hyper-active gap filling mechanism, because this involves a more risky predictive structure building process than is standardly assumed for active object gap creation in English. Filler retrieval and structural integration is still integral to the hyper-active gap filling mechanism, but the crucial difference is in what Hyper-Active Gap Filling 11 information triggers the retrieval and integration, and consequently, at what point in the sentence this process is executed. It is important to note that either of these two active gap filling mechanisms is compatible with the existing data on active object gap creation reviewed above. A filled gap effect only indicates that the gap had been created before the actual object NP is processed, but given that both hyper-active gap filling and conservative active gap filling mechanisms assume that object NP gap creation happens before or on the verb, this result is predicted by both accounts. A plausibility mismatch effect indicates that when the verb is potentially transitive, then the semantic fit between the filler and the verb is immediately assessed. This is also predicted by both accounts. The assessment of the semantic relation between the filler and the verb requires the parser to access the content of the verb, by which point the object gap position should have been created on either account. Thus, neither paradigm allows us to tease apart the two hypotheses on what kind of information is sufficient for triggering object gap creation. In the current study we test the predictions of two hypothesized mechanisms for active object gap creation processes. If English speakers construct the gap site before encountering the verb, just like speakers of verb-final languages, then English speakers risk the possibility that the verb transitivity information might not ultimately license this structure. Therefore, disruption should be observed in filler-gap configurations when the verb turns out to be intransitive, relative to transitive verbs (e.g., The party that the student arrived/planned...). According to the conservative active gap filling mechanism outlined above, the parser waits for a transitive verb before postulating the corresponding gap structure. If this is the mechanism used by English speakers, one should not expect to see disruption at an intransitive verb, since no gap that would require a transitive verb would have been posited in advance of the verb. Hyper-Active Gap Filling 12 Two previous studies are relevant to the two hypotheses about active object gap creation in English. Previous work by Pickering and Traxler (2003) examined the effect of subcategorization frequency in optionally transitive verbs (e.g., Those are the lines/props that the author spoke [about]...). It was found that readers did not take differences in subcategorization frequency into account in deciding where to posit a gap, as there was a strong preference to posit a gap in the verb object position (NP complement) even with verbs that more frequently take a PP complement. The absence of a subcategorization preference in active object gap creation could be taken to indicate that verb information is not relevant for object gap creation processes. However, all of the verbs in Pickering and Traxler’s study could grammatically accommodate an NP complement, and that the parser may therefore have relied on the transitivity information of the verb to create an object gap. Therefore, this finding does not distinguish the predictions of the two proposed mechanisms for active object gap creation. To our knowledge, the only previous test of these two active object gap creation hypotheses is in Experiment 3 of Staub (2007). The test sentences in this experiment (5a-d) manipulated the transitivity of the verb (called vs. arrived) and sentence structure (relative clause with a gap vs. simple declarative with no gap). The filler was manipulated to be an implausible object of the transitive verb (gadget-called). Under the hyper-active gap filling hypothesis, the parser in effect predicts the presence of a transitive verb, and therefore the reading processes in the gap conditions should be disrupted when the verb turns out to be intransitive, and processing should also be disrupted when the verb is transitive because of the plausibility mismatch effect. On the other hand, the conservative active gap filling mechanism postulates a gap only after checking whether the verb is capable of hosting an object NP, and therefore reading disruption is predicted only in the transitive gap condition due to the plausibility mismatch effect. Hyper-Active Gap Filling 13 (5) a. The gadget that the manager called occasionally about ... b. The manager called occasionally about the gadget ... c. The party that the student arrived promptly for ... d. The student arrived promptly for the party ... Staub (2007) found longer first-fixation durations in the transitive gap condition (5a) than in the transitive no-gap condition (5b), but no such difference was observed between the intransitive gap and no-gap conditions (5c) and (5d). This pattern of data supports the prediction of the conservative active gap filling hypothesis, suggesting that the parser does not create an object gap until it checks the transitivity information of the verb. One concern about this design, however, is whether the no-gap condition was truly a neutral baseline against which a transitivity mismatch could be measured, as the gap and no-gap conditions differed substantially in both the linear and structural position of the verb. As Staub (2007) points out, one piece of data suggesting that the control may not have been completely neutral is the fact that reading times on the intransitives were numerically (but non-significantly) shorter in the gap condition than in the no-gap condition. One notable difference between the conditions is that the gap conditions (5a) and (5c) contain an extra NP (i.e., the head of the relative clause) prior to the critical verb region in comparison to the no-gap conditions (5b) and (5d), leading to a difference in the amount of contextual information available prior to the verb. Increased contextual information can facilitate processing for subsequent lexical items (Kutas & Federmeier, 2000; Stanovich & West, 1983; Van Petten & Kutas, 1990), and for this reason, lexical access for the intransitive verb in the gap condition may have become faster and masked the potential reading time slowdown associated Hyper-Active Gap Filling 14 with the structural manipulation. In an attempt to provide a better test of the predictions of the hyper-active and conservative active gap filling accounts, the current study used relative clause islands as a control condition, which allowed the target sentences to more closely match in informational content and word position. EXPERIMENT 1 Experiment 1 was a self-paced reading study that was designed to test the predictions of the hyper-active and conservative active gap filling hypotheses, while addressing methodological concerns about previous work. We employed the transitivity mismatch paradigm used in Staub (2007) in order to test whether a verb transitivity manipulation affects reading time at the verb. Critically, in the baseline conditions the critical verb was embedded inside a relative clause structure, a syntactic ‘island’ domain that prohibits filler-gap dependency formation (Ross, 1967; for a review, see Szabolcsi & den Dikken, 2003). A sample set of stimuli is shown in (6). (6) a. Transitive, Non-island The city that the author wrote regularly about was named for an explorer. b. Transitive, Island The city that the author who wrote regularly saw was named for an explorer. c. Intransitive, Non-island The city that the author chatted regularly about was named for an explorer. d. Intransitive, Island The city that the author who chatted regularly saw was named for an explorer. Hyper-Active Gap Filling 15 A number of previous studies have shown that the parser respects island constraints in real-time syntactic processing, such that it avoids actively constructing filler-gap dependencies that span syntactic island boundaries (Kluender & Kutas, 1993; McElree & Griffith, 1998; McKinnon & Osterhout, 1996; Stowe, 1986; Traxler & Pickering, 1996; Wagers & Phillips, 2009; Yoshida, 2006). The relative clause island condition thus provided a baseline measure of reading times for the critical transitive and intransitive verbs, independent of processes of filler-gap dependency completion. The use of island configurations allowed us to address the methodological concerns with previous work. First, this design allowed us to retain the filler and the gap surrounding the island domain, such that the same amount of contextual information from the lexical items was present in advance of the critical verb region across the four conditions. Second, the critical region was closely matched across conditions (word 6 in the non-island conditions, word 7 in the island conditions), and it was also placed away from the early portion of the sentence. Furthermore, following Staub’s design, we selected transitive verbs that are implausible hosts for the filler. Under this design, the hyper-active gap filling hypothesis predicted a reading time slowdown in both the non-island transitive (6a) and the non-island intransitive (6c) conditions relative to their baseline conditions (6b) and (6d), but for a different reason in the two cases. In the transitive condition, the slowdown would reflect a plausibility mismatch effect triggered by the semantic misfit between the filler and the verb. In the intransitive condition, the slowdown would result from a transitivity mismatch effect due to the mismatch between the expected subcategorization property of the verb (i.e., transitive) and the actual subcategorization property of the verb. On the other hand, the conservative active gap filling hypothesis predicted an interaction. A reading time contrast should be observed between the non-island transitive Hyper-Active Gap Filling 16 condition (6a) and the island transitive condition (6b) due to the plausibility mismatch effect, but no corresponding contrast should be observed between the two intransitive conditions (6c) and (6d), given that the parser should not actively create an object gap in either condition. Note that the lexical difference in the critical verb region across conditions was not problematic, since the critical contrast was between non-island and island conditions within each verb type. Method Participants We recruited 32 native speakers of American English from the University of Maryland community. They all received a course credit or were paid $10 for their participation and were naïve to the purpose of the experiment. Materials We used 28 sets of four sentences like (6a) to (6d), which are all listed in Appendix A. The transitive non-island and island conditions were taken from the implausible semantic fit conditions in Omaki and Schulz (2011), who used a modified version of the plausibility manipulation materials from Traxler and Pickering (1996). Omaki and Schulz replicated Traxler and Pickering’s plausibility mismatch effect with native and non-native speakers alike, confirming that the semantic fit between the filler and the verb affects the reading time for the verb when the verb is in a gap filling (i.e., non-island) environment, but not when the verb is inside a relative clause island. Critically, it was also found that the implausible verb-filler combination in a non-island environment (e.g., city-wrote) led to a significant slow down at the verb compared to its island counterpart with the same implausible verb-filler combination. Thus, even though the current experiment did not include a plausible counterpart of the implausible Hyper-Active Gap Filling 17 transitive verb condition, we could be confident that a reading time contrast between the transitive non-island and island conditions results from the semantic misfit between the filler and the verb. In other words, the finding in Omaki and Schulz’s study supports the notion that island conditions in general can be used as baseline conditions for a reading disruption associated with active object gap creation. The intransitive conditions were modeled after the transitive conditions by replacing the optionally transitive verb with unergative or unaccusative intransitive verbs (Levin & Rappaport Hovav, 1995). The non-island and island conditions differed in the number of relative clauses: The nonisland condition had only one relative clause (the city that the author wrote/chatted regularly about) such that the object position of the verb wrote/chatted was the first potential gap position after the embedded subject was encountered, whereas in the island conditions the critical verb was embedded inside another relative clause the author who wrote/chatted regularly, such that linearly this was still the first verb but grammatically the filler should not be accessible to the verb due to the relative clause island constraint. Thus, the first verb served as the critical region for testing the plausibility and transitivity mismatch effects. All the transitive verbs were optionally transitive, such that the sentences in the island conditions were all ultimately grammatical. The subcategorization frequency of the optionally transitive verbs was not controlled, since Pickering and Traxler (2003) have demonstrated that plausibility mismatch effects are attested for optionally transitive verbs regardless of subcategorization frequency. In all four conditions the same adverb immediately followed the verb, making it possible to observe potential spill-over effects. The 28 sentence sets were counter-balanced across four lists so that each participant saw only one version of the target items and consequently read 7 tokens of each condition. In addition, 72 fillers of similar length and complexity were constructed and added to Hyper-Active Gap Filling 18 each list. Procedure The self-paced reading task was implemented on the Linger software developed by Doug Rohde (http://tedlab.mit.edu/~dr/Linger/). We used a word-by-word, non-cumulative moving window presentation (Just, Carpenter, & Woolley, 1982). In this design, each sentence initially appears as a series of dashes, and these dashes are replaced by a word from left to right every time the participant presses the space bar. In order to ensure that the participants were paying attention while reading the sentences, all sentences were followed by yes-no comprehension questions, and feedback was provided if the questions were answered incorrectly. Comprehension questions never addressed the critical filler-gap portion of the sentence. At the beginning of the experiment, participants were instructed to read at a natural pace and to answer the questions as accurately as possible. Seven practice items preceded the self-paced reading experiment, and the order of presentation was randomized for each participant. The experiment took approximately 30 minutes. Analysis The data from two items were excluded from analyses due to coding errors, and only trials in which the comprehension question was answered accurately were included in the analysis. We also analyzed the data without excluding the trials based on comprehension accuracy, but the overall pattern of results did not change. Self-paced reading times for the target sentences were examined for each successive region, although the words after the auxiliary was were combined into a single region because these lay beyond the critical regions and were unlikely to show effects relevant for the critical manipulation. Reading time data that exceeded three standard deviations from the group mean at each region and in each condition were Hyper-Active Gap Filling 19 excluded, affecting 1.7% of the data. The participant mean (F1) and item mean (F2) of the remaining reading time data for each region were submitted to a repeated measures 2 × 2 ANOVA with the factors structure type (non-island vs. island) and verb type (transitive vs. intransitive). In the critical regions, planned comparisons were conducted to test for systematic differences between non-island and island conditions within each verb type. Results Comprehension accuracy. The mean comprehension question accuracy for experimental items across participants and items was 93.0%. For the non-island conditions, the transitive items were answered with an accuracy of 93.7% (SE = 1.9), and the intransitive items with an accuracy of 94.6% (SE = 1.4). For the island conditions, the transitive items were answered with an accuracy of 91.5% (SE = 1.7), and the intransitive items with an accuracy of 92.0% (SE = 2.2). The mean accuracy did not differ reliably across conditions, although the fact that the mean accuracy for island conditions was numerically lower may reflect the complexity difference between non-island and island conditions. Reading time data. Regions were defined as in the following example: The1 city2 that3 the4 author5 (who)6 wrote7 regularly8 about/(saw)9 was10 [named for an explorer]11. The critical regions where a potential plausibility or transitivity mismatch effect was expected consist of Region 7 (i.e., the verb wrote/chatted) and the following Region 8 (i.e., the adverb regularly), in which spill-over effects could be observed. Regions 1 through 6 were predicted to show no difference across conditions, since they were lexically matched. Regions 9 through 11 could reveal reading time differences after the filler-gap dependency is completed (Region 9 hosts the true gap site), and with a possible additional difference in the island conditions, due to the complexity associated with the extra relative clause in these conditions. Hyper-Active Gap Filling 20 The region-by-region mean reading time for the transitive conditions is presented in Figure 1, and the mean region-by-region reading time for the intransitive conditions is presented in Figure 2.