Sentence Comprehension

Brothers, T. (2022). Capacity limits in sentence comprehension: Evidence from dual-task judgements and event-related potentials. Cognition , 225, 105153.Abstract

There is an ongoing controversy over whether readers can access the meaning of multiple words, simultaneously. To date, different experimental methods have generated seemingly contradictory evidence in support of serial or parallel processing accounts. For example, dual-task studies suggest that readers can process a maximum of one word at a time (White, Palmer & Boynton, 2018), while ERP studies have demonstrated neural priming effects that are more consistent with parallel activation (Wen, Snell & Grainger, 2019). To help reconcile these views, I measured neural responses and behavioral accuracy in a dual-task sentence comprehension paradigm. Participants saw masked sentences and two-word phrases and had to judge whether or not they were grammatical. Grammatically correct sentences (This girl is neat) produced smaller N400 responses compared to scrambled sentences (Those girl is fled): an N400 sentence superiority effect. Critically, participants' grammaticality judgements on the same trials showed striking capacity limitations, with dual-task deficits closely matching the predictions of a serial, all-or-none processing account. Together, these findings suggest that the N400 sentence superiority effect is fully compatible with serial word recognition, and that readers are unable to process multiple sentence positions simultaneously.

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    Brothers, T., Zeitlin, M., Choi Perrachione, A., Choi, C., & Kuperberg, G. R. (2021). Domain-general conflict monitoring predicts neural and behavioral indices of linguistic error processing during reading comprehension. Journal of Experimental Psychology: General.Abstract
    The ability to detect and respond to linguistic errors is critical for successful reading comprehension, but these skills can vary considerably across readers. In the current study, healthy adults (age 18-35) read short discourse scenarios for comprehension while monitoring for the presence of semantic anomalies. Using a factor analytic approach, we examined if performance in nonlinguistic conflict monitoring tasks (Stroop, AX-CPT) would predict individual differences in neural and behavioral measures of linguistic error processing. Consistent with this hypothesis, domain-general conflict monitoring predicted both readers' end-of-trial acceptability judgments and the amplitude of a late neural response (the P600) evoked by linguistic anomalies. The influence on the P600 was nonlinear, suggesting that online neural responses to linguistic errors are influenced by both the effectiveness and efficiency of domain-general conflict monitoring. These relationships were also highly specific and remained after controlling for variability in working memory capacity and verbal knowledge. Finally, we found that domain-general conflict monitoring also predicted individual variability in measures of reading comprehension, and that this relationship was partially mediated by behavioral measures of linguistic error detection. These findings inform our understanding of the role of domain-general executive functions in reading comprehension, with potential implications for the diagnosis and treatment of language impairments. 
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    Brothers, T., & Kuperberg, G. R. (2021). Word predictability effects are linear, not logarithmic: Implications for probabilistic models of sentence comprehension. Journal of Memory and Language , 116, 1041742.Abstract

    During language comprehension, we routinely use information from the prior context to help identify the meaning of individual words. While measures of online processing difficulty, such as reading times, are strongly influenced by contextual predictability, there is disagreement about the mechanisms underlying this lexical predictability effect, with different models predicting different linking functions – linear (Reichle, Rayner, & Pollatsek, 2003) or logarithmic (Levy, 2008). To help resolve this debate, we conducted two highly-powered experiments (self-paced reading, N = 216; cross-modal picture naming, N = 36), and a meta-analysis of prior eye-tracking while reading studies (total N = 218). We observed a robust linear relationship between lexical predictability and word processing times across all three studies. Beyond their methodological implications, these findings also place important constraints on predictive processing models of language comprehension. In particular, these results directly contradict the empirical predictions of surprisal theory, while supporting a proportional pre-activation account of lexical prediction effects in comprehension.

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      Wang, L., Wlotko, E., Alexander, E., Schoot, L., Kim, M., Warnke, L., & Kuperberg, G. (2020). Neural evidence for the prediction of animacy features during language comprehension: Evidence from MEG and EEG Representational Similarity Analysis. Journal of Neuroscience , 40 (16), 3278-3291.Abstract

      It has been proposed that people can generate probabilistic predictions at multiple levels of representation during language comprehension. We used magnetoencephalography (MEG) and electroencephalography (EEG), in combination with representational similarity analysis, to seek neural evidence for the prediction of animacy features. In two studies, MEG and EEG activity was measured as human participants (both sexes) read three-sentence scenarios. Verbs in the final sentences constrained for either animate or inanimate semantic features of upcoming nouns, and the broader discourse context constrained for either a specific noun or for multiple nouns belonging to the same animacy category. We quantified the similarity between spatial patterns of brain activity following the verbs until just before the presentation of the nouns. The MEG and EEG datasets revealed converging evidence that the similarity between spatial patterns of neural activity following animate-constraining verbs was greater than following inanimate-constraining verbs. This effect could not be explained by lexical-semantic processing of the verbs themselves. We therefore suggest that it reflected the inherent difference in the semantic similarity structure of the predicted animate and inanimate nouns. Moreover, the effect was present regardless of whether a specific word could be predicted, providing strong evidence for the prediction of coarse-grained semantic features that goes beyond the prediction of individual words.

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      Kuperberg, G. R., Brothers, T., & Wlotko, E. (2020). A Tale of Two Positivities and the N400: Distinct neural signatures are evoked by confirmed and violated predictions at different levels of representation. Journal of Cognitive Neuroscience , 32 (1), 12-35.Abstract
      It has been proposed that hierarchical prediction is a fundamental computational principle underlying neurocognitive processing. Here we ask whether the brain engages distinct neurocognitive mechanisms in response to inputs that fulfill versus violate strong predictions at different levels of representation during language comprehension. Participants read three-sentence scenarios in which the third sentence constrained for a broad event structure, e.g. {Agent caution animate-Patient}. High constraint contexts additionally constrained for a specific event/lexical item, e.g. a two-sentence context about a beach, lifeguards and sharks constrained for the event, {Lifeguards cautioned Swimmers} and the specific lexical item, “swimmers”. Low constraint contexts did not constrain for any specific event/lexical item. We measured ERPs on critical nouns that fulfilled and/or violated each of these constraints. We found clear, dissociable effects to fulfilled semantic predictions (a reduced N400), to event/lexical prediction violations (an increased late frontal positivity), and to event structure/animacy prediction violations (an increased late posterior positivity/P600). We argue that the late frontal positivity reflects a large change in activity associated with successfully updating the comprehender’s current situation model with new unpredicted information. We suggest that the late posterior positivity/P600 is triggered when the comprehender detects a conflict between the input and her model of the communicator and communicative environment. This leads to an initial failure to incorporate the unpredicted input into the situation model, which may be followed by second-pass attempts to make sense of the discourse through reanalysis, repair, or reinterpretation. Together, these findings provide strong evidence that confirmed and violated predictions at different levels of representation manifest as distinct spatiotemporal neural signatures.
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      Wang, L., Kuperberg, G. R., & Jensen, O. (2018). Specific lexico-semantic predictions are associated with unique spatial and temporal patterns of neural activity. eLife , 7 e39061.Abstract
      We used Magnetoencephalography (MEG) in combination with Representational Similarity Analysis to probe neural activity associated with distinct, item-specific lexico-semantic predictions during language comprehension. MEG activity was measured as participants read highly constraining sentences in which the final words could be predicted. Before the onset of the predicted words, both the spatial and temporal patterns of brain activity were more similar when the same words were predicted than when different words were predicted. The temporal patterns localized to the left inferior and medial temporal lobe. These findings provide evidence that unique spatial and temporal patterns of neural activity are associated with item-specific lexico-semantic predictions. We suggest that the unique spatial patterns reflected the prediction of spatially distributed semantic features associated with the predicted word, and that the left inferior/medial temporal lobe played a role in temporally “binding” these features, giving rise to unique lexico-semantic predictions.
      Full Text Supplementary Material: Figures Supplementary Materials: Author Response Supplementary Material: Chinese/ English Stimuli
      Rabagliati, H., Delaney-Busch, N., Snedeker, J., & Kuperberg, G. R. (2018). Spared bottom-up but impaired top-down effects during naturalistic language processing in schizophrenia: Evidence from the visual world paradigm. Psychological Medicine , 49 (58), 1335-1345. Full TextAbstract


      People with schizophrenia process language in unusual ways, but the causes of these abnormalities are unclear. In particular, it has proven difficult to empirically disentangle explanations based on impairments in the top-down processing of higher-level information from those based on the bottom-up processing of lower-level information.



      To distinguish these accounts, we used visual world eye-tracking, a paradigm that measures spoken language processing during real-world interactions. Participants listened to and then acted out syntactically ambiguous spoken instructions (e.g., “tickle the frog with the feather”, which could either specify how to tickle a frog, or which frog to tickle). We contrasted how 24 people with schizophrenia and 24 demographically-matched controls used two types of lower-level information (prosody and lexical representations) and two types of higher-level information (pragmatic and discourse-level representations) to resolve the ambiguous meanings of these instructions. Eye-tracking allowed us to assess how participants arrived at their interpretation in real time, while recordings of participants’ actions measured how they ultimately interpreted the instructions.



      We found a striking dissociation in participants’ eye movements: the two groups were similarly adept at using lower-level information to immediately constrain their interpretations of the instructions, but only controls showed evidence of fast top-down use of higher-level information. People with schizophrenia, nonetheless, did eventually reach the same interpretations as controls.



      These data suggest that language abnormalities in schizophrenia partially result from a failure to use higher-level information in a top-down fashion, to constrain the interpretation of language as it unfolds in real time.
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      Kuperberg, G. R., Ditman, T., & Choi Perrachione, A. (2018). When proactivity fails: An electrophysiological study of establishing reference in schizophrenia. Biological Psychiatry: Cognitive Neuroscience and Neuroimaging , 3 (1), 77-87. Full TextAbstract

      Background: Schizophrenia is characterized by abnormalities in referential communication, which may be linked to more general deficits in proactive cognitive control. We used event-related potentials (ERPs) to probe the timing and nature of the neural mechanisms engaged as people with schizophrenia linked pronouns to their preceding referents during word-by-word sentence comprehension.

      Methods: We measured ERPs to pronouns in two-clause sentences from 16 people with schizophrenia and 20 demographically-matched control participants. Our design crossed the number of potential referents (1-referent, 2-referent) with whether the pronoun matched the gender of its preceding referent(s) (matching, mismatching). This gave rise to four conditions: (1) 1-referent matching (“…Edward took courses in accounting but he…”), (2) 2-referent matching (“…Edward and Phillip took courses but he…”), (3) 1-referent mismatching (“…Edward took courses in accounting but she…”), and (4) 2-referent mismatching (“…Edward and Phillip took courses but she…”).

      Results: Consistent with previous findings, healthy controls produced a larger left anteriorly-distributed negativity between 400-600ms to 2-referent matching than to 1-referent matching pronouns (the “Nref effect”). In contrast, people with schizophrenia produced a larger centro-posterior positivity effect between 600-800ms. Both patient and control groups produced a larger positivity between 400-800ms to mismatching than to matching pronouns.

      Conclusions: These findings suggest that proactive mechanisms of referential processing, reflected by the Nref effect, are impaired in schizophrenia, while reactive mechanisms, reflected by the positivity effects, are relatively spared. Indeed, patients may compensate for proactive deficits by retro-actively engaging with context to influence the processing of inputs at a later stage of analysis.

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      Yan, S., Kuperberg, G. R., & Jaeger, T. F. (2017). Prediction (or not) during language processing. A commentary on Nieuwland et al. (2017) and Delong et al. (2005). bioRxiv. Full textAbstract
      The extent to which language processing involves prediction of upcoming inputs remains a question of ongoing debate. One important data point comes from DeLong et al. (2005) who reported that an N400-like event-related potential correlated with a probabilistic index of upcoming input. This result is often cited as evidence for gradient probabilistic prediction of form and/or semantics, prior to the bottom-up input becoming available. However, a recent multi-lab study reports a failure to find these effects (Nieuwland et al., 2017). We review the evidence from both studies, including differences in the design and analysis approach between them. Building on over a decade of research on prediction since DeLong et al. (2005)'s original study, we also begin to spell out the computational nature of predictive processes that one might expect to correlate with ERPs that are evoked by a functional element whose form is dependent on an upcoming predicted word. For paradigms with this type of design, we propose an index of anticipatory processing, Bayesian surprise, and apply it to the updating of semantic predictions. We motivate this index both theoretically and empirically. We show that, for studies of the type discussed here, Bayesian surprise can be closely approximated by another, more easily estimated information theoretic index, the surprisal (or Shannon information) of the input. We re-analyze the data from Nieuwland and colleagues using surprisal rather than raw probabilities as an index of prediction. We find that surprisal is gradiently correlated with the amplitude of the N400, even in the data shared by Nieuwland and colleagues. Taken together, our review suggests that the evidence from both studies is compatible with anticipatory semantic processing. We do, however, emphasize the need for future studies to further clarify the nature and degree of form prediction, as well as its neural signatures, during language comprehension.
      Kuperberg, G. R. (2016). Separate streams or probabilistic inference? What the N400 can tell us about the comprehension of events. Language, Cognition and Neuroscience , 31 (5), 602-616. Full text Abstract

      Since the early 2000s, several ERP studies have challenged the assumption that we always use syntactic contextual information to influence semantic processing of incoming words, as reflected by the N400 component. One approach for explaining these findings is to posit distinct semantic and syntactic processing mechanisms, each with distinct time courses. While this approach can explain specific datasets, it cannot account for the wider body of findings. I propose an alternative explanation: a dynamic generative framework in which our goal is to infer the underlying event that best explains the set of inputs encountered at any given time. Within this framework, combinations of semantic and syntactic cues with varying reliabilities are used as evidence to weight probabilistic hypotheses about this event. I further argue that the computational principles of this framework can be extended to understand how we infer situation models during discourse comprehension, and intended messages during spoken communication.

      Wittenberg, E., Paczynski, M., Wiese, H., Jackendoff, R., & Kuperberg, G. R. (2014). The difference between “giving a rose” and “giving a kiss”: A sustained anterior negativity to the light verb construction. Journal of Memory and Language , (73), 31 - 42. Full TextAbstract
      We used event-related potentials (ERPs) to investigate the neurocognitive mechanisms associated with processing light verb constructions such as “give a kiss”. These constructions consist of a semantically underspecified light verb (“give”) and an event nominal that contributes most of the meaning and also activates an argument structure of its own (“kiss”). This creates a mismatch between the syntactic constituents and the semantic roles of a sentence. Native speakers read German verb-final sentences that contained light verb constructions (e.g., “Julius gave Anne a kiss”), non-light constructions (e.g., “Julius gave Anne a rose”), and semantically anomalous constructions (e.g., *“Julius gave Anne a conversation”). ERPs were measured at the critical verb, which appeared after all its arguments. Compared to non-light constructions, the light verb constructions evoked a widely distributed, frontally focused, sustained negative-going effect between 500 and 900 ms after verb onset. We interpret this effect as reflecting working memory costs associated with complex semantic processes that establish a shared argument structure in the light verb constructions.
      Supplementary Material: Sample Stimuli Supplementary Material: Full Stimuli List (German Only) Supplementary Materials: Analysis of Sentence Final Words
      Paczynski, M., Jackendoff, R., & Kuperberg, G. R. (2014). When events change their nature: The neurocognitive mechanisms underlying aspectual coercion. The Journal of Cognitive Neuroscience , 29 (9), 1905-17. Full TextAbstract
      The verb “pounce” describes a single, near-instantaneous event. Yet, we easily understand that, “For several minutes the cat pounced…” describes a situation in which multiple pounces occurred, although this interpretation is not overtly specified by the sentenceʼs syntactic structure or by any of its individual words—a phenomenon known as “aspectual coercion.” Previous psycholinguistic studies have reported processing costs in association with aspectual coercion, but the neurocognitive mechanisms giving rise to these costs remain contentious. Additionally, there is some controversy about whether readers commit to a full interpretation of the event when the aspectual information becomes available, or whether they leave it temporarily underspecified until later in the sentence. Using ERPs, we addressed these questions in a design that fully crossed context type (punctive, durative, frequentative) with verb type (punctive, durative). We found a late, sustained negativity to punctive verbs in durative contexts, but not in frequentative (e.g., explicitly iterative) contexts. This effect was distinct from the N400 in both its time course and scalp distribution, suggesting that it reflected a different underlying neurocognitive mechanism. We also found that ERPs to durative verbs were unaffected by context type. Together, our results provide strong evidence that neural activity associated with aspectual coercion is driven by the engagement of a morphosyntactically unrealized semantic operator rather than by violations of real-world knowledge, more general shifts in event representation, or event iterativity itself. More generally, our results add to a growing body of evidence that a set of late-onset sustained negativities reflect elaborative semantic processing that goes beyond simply combining the meaning of individual words with syntactic structure to arrive at a final representation of meaning.
      Wittenberg, E., Jackendoff, R., Kuperberg, G., Paczynski, M., Snedeker, J., Wiese, H., & Wittenberg, E. (2014). The processing and representation of light verb constructions. In Bachrach, A., Roy, I. and Stockall, L. (Eds): Structuring the Argument: Multidisciplinary research on verb argument structure (pp. 61-80) . John Benjamins Publishing Company.
      Kuperberg, G. (2013). The proactive comprehender: What event-related potentials tell us about the dynamics of reading comprehension. In Miller, B., Cutting, L., & McCardle, P (Eds): Unraveling the Behavioral, Neurobiological, and Genetic Components of Reading Comprehension (pp. 176-19) . Paul Brookes Publishing. Full Text
      Paczynski, M., & Kuperberg, G. R. (2012). Multiple Influences of Semantic Memory on Sentence Processing: Distinct Effects of Semantic Relatedness on Violations of Real-World Event/State Knowledge and Animacy Selection Restrictions. J Mem Lang , 67 (4), 426-448. Full TextAbstract
      We aimed to determine whether semantic relatedness between an incoming word and its preceding context can override expectations based on two types of stored knowledge: real-world knowledge about the specific events and states conveyed by a verb, and the verb's broader selection restrictions on the animacy of its argument. We recorded event-related potentials on post-verbal Agent arguments as participants read and made plausibility judgments about passive English sentences. The N400 evoked by incoming animate Agent arguments that violated expectations based on real-world event/state knowledge, was strongly attenuated when they were semantically related to the context. In contrast, semantic relatedness did not modulate the N400 evoked by inanimate Agent arguments that violated the preceding verb's animacy selection restrictions. These findings suggest that, under these task and experimental conditions, semantic relatedness can facilitate processing of post-verbal animate arguments that violate specific expectations based on real-world event/state knowledge, but only when the semantic features of these arguments match the coarser-grained animacy restrictions of the verb. Animacy selection restriction violations also evoked a P600 effect, which was not modulated by semantic relatedness, suggesting that it was triggered by propositional impossibility. Together, these data indicate that the brain distinguishes between real-world event/state knowledge and animacy-based selection restrictions during online processing.
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      Paczynski, M., & Kuperberg, G. R. (2011). Electrophysiological Evidence for Use of the Animacy Hierarchy, but not Thematic Role Assignment, During Verb Argument Processing. Lang Cogn Process , 26 (9), 1402-1456. Full TextAbstract
      Animacy is known to play an important role in language processing and production, but debate remains as to how it exerts its effects: 1) through links to syntactic ordering, 2) through inherent differences between animate and inanimate entities in their salience/lexico-semantic accessibility, 3) through links to specific thematic roles. We contrasted these three accounts in two event related potential (ERP) experiments examining the processing of direct object arguments in simple English sentences. In Experiment 1, we found a larger N400 to animate than inanimate direct object arguments assigned the Patient role, ruling out the second account. In Experiment 2 we found no difference in the N400 evoked by animate direct object arguments assigned the Patient role (prototypically inanimate) and those assigned the Experiencer role (prototypically animate), ruling out the third account. We therefore suggest that animacy may impact processing through a direct link to syntactic linear ordering, at least on post-verbal arguments in English. We also examined processing on direct object arguments that violated the animacy-based selection restriction constraints of their preceding verbs. These violations evoked a robust P600, which was not modulated by thematic role assignment or reversibility, suggesting that the so-called semantic P600 is driven by overall propositional impossibility, rather than thematic role reanalysis.
      Supplementary Figures Supplementary Materials
      Kuperberg, G. R., Choi, A., Cohn, N., Paczynski, M., & Jackendoff, R. (2010). Electrophysiological correlates of complement coercion. J Cogn Neurosci , 22 (12), 2685-701. Full TextAbstract
      This study examined the electrophysiological correlates of complement coercion. ERPs were measured as participants read and made acceptability judgments about plausible coerced sentences, plausible noncoerced sentences, and highly implausible animacy-violated sentences ("The journalist began/wrote/astonished the article before his coffee break"). Relative to noncoerced complement nouns, the coerced nouns evoked an N400 effect. This effect was not modulated by the number of possible activities implied by the coerced nouns (e.g., began reading the article; began writing the article) and did not differ either in magnitude or scalp distribution from the N400 effect evoked by the animacy-violated complement nouns. We suggest that the N400 modulation to both coerced and animacy-violated complement nouns reflected different types of mismatches between the semantic restrictions of the verb and the semantic properties of the incoming complement noun. This is consistent with models holding that a verb's semantic argument structure is represented and stored at a distinct level from its syntactic argument structure. Unlike the coerced complement noun, the animacy-violated nouns also evoked a robust P600 effect, which may have been triggered by the judgments of the highly implausible (syntactically determined) meanings of the animacy-violated propositions. No additional ERP effects were seen in the coerced sentences until the sentence-final word that, relative to sentence-final words in the noncoerced sentences, evoked a sustained anteriorly distributed positivity. We suggest that this effect reflected delayed attempts to retrieve the specific event(s) implied by coerced complement nouns.
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      De Grauwe, S., Swain, A., Holcomb, P. J., Ditman, T., & Kuperberg, G. R. (2010). Electrophysiological insights into the processing of nominal metaphors. Neuropsychologia , 48 (7), 1965-84. Full TextAbstract
      We used event-related potentials (ERPs) to examine the time-course of processing metaphorical and literal sentences in the brain. ERPs were measured to sentence-final (Experiment 1) and mid-sentence (Experiment 2) critical words (CWs) as participants read and made plausibility judgments about familiar nominal metaphors ("A is a B") as well as literal and semantically anomalous sentences of the same form. Unlike the anomalous words, which evoked a robust N400 effect (on the CW in experiments 1 and 2 as well as on the sentence-final word in experiment 2), CWs in the metaphorical, relative to the literal, sentences only evoked an early, localized N400 effect that was over by 400ms after CW onset, suggesting that, by this time, their metaphorical meaning had been accessed. CWs in the metaphorical sentences also evoked a significantly larger LPC (Late Positive Component) than in the literal sentences. We suggest that this LPC reflected additional analysis that resolved a conflict between the implausibility of the literal sentence interpretation and the match between the metaphorical meaning of the CW, the context and stored information within semantic memory, resulting from early access to both literal and figurative meanings of the CWs.
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      Nieuwland, M. S., Ditman, T., & Kuperberg, G. R. (2010). On the incrementality of pragmatic processing: An ERP investigation of informativeness and pragmatic abilities. J Mem Lang , 63 (3), 324-346. Full TextAbstract
      In two event-related potential (ERP) experiments, we determined to what extent Grice's maxim of informativeness as well as pragmatic ability contributes to the incremental build-up of sentence meaning, by examining the impact of underinformative versus informative scalar statements (e.g. "Some people have lungs/pets, and…") on the N400 event-related potential (ERP), an electrophysiological index of semantic processing. In Experiment 1, only pragmatically skilled participants (as indexed by the Autism Quotient Communication subscale) showed a larger N400 to underinformative statements. In Experiment 2, this effect disappeared when the critical words were unfocused so that the local underinformativeness went unnoticed (e.g., "Some people have lungs that…"). Our results suggest that, while pragmatic scalar meaning can incrementally contribute to sentence comprehension, this contribution is dependent on contextual factors, whether these are derived from individual pragmatic abilities or the overall experimental context.
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      Osterhout, L., Kim, A., & Kuperberg, G. (2008). The neurobiology of sentence comprehension. In M. Spivey, M. Joannisse, & K. McRae (Eds): The Cambridge Handbook of Psycholinguistics (pp. 365-389) . Cambridge University Press. Full Text