Please check Researchgate for pdf copies of many of our papers:
https://www.researchgate.net/profile/Tamara_Swaab/research

• Traxler, M.J. & Swaab, T.Y. (2025). Predictive Processing and Language. In: Andrews, E. & Kiran, S. (Eds.). The Cambridge Handbook of Language and Brain. Cambridge University Press. ISBN:9781009202336
• Swaab, T.Y. (2025). Language (Chapter 11). In: Gazzaniga et al., Cognitive Neuroscience: The Biology of the Mind. (6th Edition). W.W. Norton Pub.: New York (Textbook).
• Costa, C., Pezzetta, R., Toffalini, E., Grassi, M., Cona, G., Miniussi, C., Bauer, P., Borgomaneri, S., Brysbaert, M., Chambers, C., Edelstyn, N., Eerland, A., Gilbert, S., Nitsche, M., Poldrack, R., Puce, A., Ridderinkhof, K. R., Swaab, T., Umiltà, C., Wiener, M., & Scarpazza, C. (in press). Enhancing the quality and reproducibility of research: Preferred Evaluation of Cognitive and Neuropsychological Studies – The PECANS statement for human studies. Behavior Research Methods.
• Trammel, T., Khodayari, N., Luck, S. J., Traxler, M. J., & Swaab, T. Y. (2023). Decoding semantic relatedness and prediction from EEG: A classification method comparison. NeuroImage, 277, 120268.
  • Abstract: Machine-learning (ML) decoding methods have become a valuable tool for analyzing information represented in electroencephalogram (EEG) data. However, a systematic quantitative comparison of the performance of major ML classifiers for the decoding of EEG data in neuroscience studies of cognition is lacking. Using EEG data from two visual word-priming experiments examining well-established N400 effects of prediction and semantic relatedness, we compared the performance of three major ML classifiers that each use different algorithms: support vector machine (SVM), linear discriminant analysis (LDA), and random forest (RF). We separately assessed the performance of each classifier in each experiment using EEG data averaged over cross-validation blocks and using single-trial EEG data by comparing them with analyses of raw decoding accuracy, effect size, and feature importance weights. The results of these analyses demonstrated that SVM outperformed the other ML methods on all measures and in both experiments.
• Beier, E., Breska, A., Miller, L., Oganian, Y., Mangun, G., & Swaab, T.Y. (2023). The role of anticipatory attention during spoken language comprehension and its encoding in alpha amplitude modulations. Poster presented at 30th Anniversary Meeting of the Cognitive Neuroscience Society (CNS 2023), San Francisco, CA, USA. DOI: 21.11116/0000-000C-EA0A-2
  • Abstract: Spoken language rapidly conveys information over time. Current theories hold that listeners make continuous predictions about the importance and timing of information as it arrives, but the underlying neurocognitive mechanisms remain unclear. The goal of this ongoing project is to examine whether linguistic cues guide anticipatory attention toward upcoming linguistic information. Participants heard an Early Focus question ('Which man was wearing the hat?') or a Late Focus question ('What hat was the man wearing?'), focusing either an Early Target or a Late Target word in the following sentence ('The man on the CORNER was wearing the DARK hat'; target words in all caps). Previous findings (Beier & Ferreira, 2022) revealed faster reaction times to the Early Target word when focused with the Early Focus question than when defocused with the Late Focus question, and vice versa for the Late Target word. This study extends these findings by additionally recording EEG and observing changes in neural dynamics associated with attentional allocation, including anticipatory alpha suppression. We predict that alpha amplitude prior to the Early and Late target words will vary as a function of whether they were focused through the preceding questions. Furthermore, we will test whether alpha prior to each target word correlates with the amplitude of the N400 elicited by the target words, as well as with memory for the target words in a subsequent memory test. Overall, this study integrates interdisciplinary lines of research by investigating the role of anticipatory attention mechanisms in language comprehension.
• Sendek, K., Corina, D., Cates, D. Traxler, M.J., Swaab, T.Y. (2023). L1 referential features influence pronoun reading in L2 for deaf, ASL-English bilinguals. Bilingualism, Language and Cognition, 6(4), 738-750. https://doi.org/10.1017/S1366728923000020
  • Abstract: Referential processing relies on similar cognitive functions across languages – in particular, working memory. However, this has only been investigated in spoken languages with highly similar referential systems. In contrast to spoken languages, American Sign Language (ASL) uses a spatial referential system. It is unknown whether the referential system of ASL (L1) impacts referential processing in English (L2). This cross-language impact may be of particular importance for deaf, bimodal bilinguals who sign in ASL and read in English. Self-paced reading times of pronouns in English texts were compared between ASL–English bimodal bilinguals and Chinese–English unimodal bilinguals. The results showed that L1 referential characteristics influenced pronoun reading time in L2. Furthermore, in contrast to Chinese–English bilinguals, ASL–English bilinguals’ referential processing during reading of English texts relied on vocabulary knowledge – not working memory. These findings emphasize the need to expand current theories of referential processing to include more diverse types of language transfer.
• Dave, S., Brothers, T., Hoversten, L. J., Traxler, M. J., & Swaab, T. Y. (2021). Cognitive control mediates age-related changes in flexible anticipatory processing during listening comprehension. Brain Research, 1768, 147573. DOI: 10.1016/j.brainres.2021.147573
  • Abstract: Effective listening comprehension not only requires processing local linguistic input, but also necessitates incorporating contextual cues available in the global communicative environment. Local sentence processing can be facilitated by pre-activation of likely upcoming input, or predictive processing. Recent evidence suggests that young adults can flexibly adapt local predictive processes based on cues provided by the global communicative environment, such as the reliability of specific speakers. Whether older comprehenders can also flexibly adapt to global contextual cues is currently unknown. Moreover, it is unclear whether the underlying mechanisms supporting local predictive processing differ from those supporting adaptation to global contextual cues. Critically, it is unclear whether these mechanisms change as a function of typical aging. We examined the flexibility of prediction in young and older adults by presenting sentences from speakers whose utterances were typically more or less predictable (i.e., reliable speakers who produced expected words 80% of the time, versus unreliable speakers who produced expected words 20% of the time). For young listeners, global speaker reliability cues modulated neural effects of local predictability on the N400. In contrast, older adults, on average, did not show global modulation of local processing. Importantly, however, cognitive control (i.e., Stroop interference effects) mediated age-related reductions in sensitivity to the reliability of the speaker. Both young and older adults with high cognitive control showed greater N400 effects of predictability during sentences produced by a reliable speaker, suggesting that cognitive control is required to regulate the strength of top-down predictions based on global contextual information. Critically, cognitive control predicted sensitivity to global speaker-specific information but not local predictability cues, suggesting that predictive processing in local sentence contexts may be supported by separable neural mechanisms from adaptation of prediction as a function of global context. These results have important implications for interpreting age-related change in predictive processing, and for drawing more generalized conclusions regarding domain-general versus language-specific accounts of prediction.
• Bousquet, K., Swaab, T.Y., & Long, D.L. (2020) The use of context in resolving syntactic ambiguity: structural and semantic influences, Language, Cognition and Neuroscience, 35:1, 43-57, DOI: 10.1080/23273798.2019.1622750
  • Abstract: Verb bias facilitates parsing of temporarily ambiguous sentences, but it is unclear when and how comprehenders use probabilistic knowledge about the combinatorial properties of verbs in context. In a self-paced reading experiment, participants read direct object/sentential complement sentences. Reading time in the critical region was investigated as a function of three forms of bias: structural bias (the frequency with which a verb appears in direct object/sentential complement sentences), lexical bias (the simple co-occurrence of verbs and other lexical items), and global bias (obtained from norming data about the use of verbs with specific noun phrases). For reading times at the critical word, structural bias was the only reliable predictor. However, global bias was superior to structural and lexical bias at the post-critical word and for offline acceptability ratings. The results suggest that structural information about verbs is available immediately, but that context-specific, semantic information becomes increasingly informative as processing proceeds.
• Brothers, T., Dave, S., Hoversten, L. J., Traxler, M. J., & Swaab, T. Y. (2019). Flexible predictions during listening comprehension: Speaker reliability affects anticipatory processes. Neuropsychologia, 135, 107225. DOI: 10.1016/j.neuropsychologia.2019.107225
  • Abstract: During listening comprehension, the identification of individual words can be strongly influenced by properties of the preceding context. While sentence context can facilitate both behavioral and neural responses, it is unclear whether these effects can be attributed to the pre-activation of lexico-semantic features or the facilitated integration of contextually congruent words. Moreover, little is known about how statistics of the broader language environment, or information about the current speaker, might shape these facilitation effects. In the present study, we measured neural responses to predictable and unpredictable words as participants listened to sentences for comprehension. Critically, we manipulated the reliability of each speaker's utterances, such that individual speakers either tended to complete sentences with words that were highly predictable (reliable speaker) or with words that were unpredictable but still plausible (unreliable speaker). As expected, the amplitude of the N400 was reduced for locally predictable words, but, critically, these context effects were also modulated by speaker identity. Sentences from a reliable speaker showed larger facilitation effects with an earlier onset, suggesting that listeners engaged in enhanced anticipatory processing when a speaker's behavior was more predictable. This finding suggests that listeners can implicitly track the reliability of predictive cues in their environment and use these statistics to adaptively regulate predictive processing.
• Boudewyn, M.A., Blalock, A.R., Long, D.L., & Swaab, T.Y., (2019). Adaptation to Animacy Violations during Listening Comprehension. Cognitive Affective and Behavioral Neuroscience, 19, 1247–1258. DOI: 10.3758/s13415-019-00735-x
  • Abstract: The goal of this study was to examine adaptation to various types of animacy violations in cartoon-like stories. We measured the event-related potentials (ERPs) elicited by words at the beginning, middle, and end of four-sentence stories in order to examine adaptation over time to conflicts between stored word knowledge and context-derived meaning (specifically, to inanimate objects serving as main characters, as they might in a cartoon). The fourth and final sentence of each story contained a predicate that required either an animate or an inanimate subject. The results showed that listeners quickly adapted to stories in the Inanimate Noun conditions, consistent with previous research (Filik & Leuthold, 2008; Nieuwland & Van Berkum, 2006). They showed evidence of processing difficulty for animacy-requiring predicates in the Inanimate Noun conditions in Sentence 1, but the effect dissipated in Sentences 2 and 3. In Sentences 2 and 4, we measured ERPs at three critical points where it was possible to observe the influence of both context-based expectations and expectations from prior knowledge on processing. Overall, the pattern of results demonstrates how listeners flexibly adapt to unusual, conflict-ridden input, using previous context to generate expectations about upcoming input, but that current context is weighted appropriately in combination with expectations from background knowledge and prior language experience.
• Johns, C. L., Long, D. L., & Swaab, T. Y. (2019). Processing pronouns with real-world referents: An electrophysiological investigation. DOI: 10.31219/osf.io/6cbq5
  • Abstract: Investigations of coreferential processing typically require participants to link anaphors with semantically underspecified (“empty”) discourse entities. However, outside the laboratory, anaphors often refer to people, objects, or events about which we possess extensive background knowledge. In addition, recent evidence indicates that comprehenders experience processing difficulty when sentence characters are semantically similar. In the current study we examined whether activating pre-existing real-world knowledge about antecedents influenced coreferential processing in a developing sentence context. Event-related potentials were recorded as participants read sentences containing ambiguous pronouns. Antecedents were either “empty” or were real, well-known individuals. In addition, pronouns either matched or mismatched the sex of their antecedents. Mismatching anaphors elicited a P600 effect whose amplitude was significantly greater when sentence characters were real. Moreover, matching pronouns elicited a P600-like effect when their antecedents were semantically “empty”. Our results suggest that the presence of high-quality representations in a discourse model facilitates coreferential processing.
• Dave, S., Brothers, T. A., Traxler, M. J., Ferreira, F., Henderson, J. M., & Swaab, T. Y. (2018). Electrophysiological Evidence for Preserved Primacy of Lexical Prediction in Aging. Neuropsychologia, 117, 135–147. DOI: 10.1016/j.neuropsychologia.2018.05.023
  • Abstract: Young adults show consistent neural benefits of predictable contexts when processing upcoming words, but these benefits are less clear-cut in older adults. Here we disentangle the neural correlates of prediction accuracy and contextual support during word processing, in order to test current theories that suggest that neural mechanisms underlying predictive processing are specifically impaired in older adults. During a sentence comprehension task, older and younger readers were asked to predict passage-final words and report the accuracy of these predictions. Age-related reductions were observed for N250 and N400 effects of prediction accuracy, as well as for N400 effects of contextual support independent of prediction accuracy. Furthermore, temporal primacy of predictive processing (i.e., earlier facilitation for successful predictions) was preserved across the lifespan, suggesting that predictive mechanisms are unlikely to be uniquely impaired in older adults. In addition, older adults showed prediction effects on frontal post-N400 positivities (PNPs) that were similar in amplitude to PNPs in young adults. Previous research has shown correlations between verbal fluency and lexical prediction in older adult readers, suggesting that the production system may be linked to capacity for lexical prediction, especially in aging. The current study suggests that verbal fluency modulates PNP effects of contextual support, but not prediction accuracy. Taken together, our findings suggest that aging does not result in specific declines in lexical prediction.
• Dave, S., Brothers, T., & Swaab, T.Y. (2018). 1/f Neural Noise and Electrophysiological Indices of Contextual Prediction in Normative Aging. Brain Research. DOI: 10.1016/j.brainres.2018.04.007.
  • Abstract: Prediction of upcoming words during reading has been suggested to enhance the efficiency of discourse processing. Emerging models have postulated that predictive mechanisms require synchronous firing of neural networks, but to date, this relationship has been investigated primarily through oscillatory activity in narrow frequency bands. A recently-developed measure proposed to reflect broadband neural activity – and thereby synchronous neuronal firing – is 1/f neural noise extracted from EEG spectral power. Previous research has indicated that this measure of 1/f neural noise changes across the lifespan, and these neural changes predict age-related behavioral impairments in visual working memory. Using a cross-sectional sample of young and older adults, we examined age-related changes in 1/f neural noise and whether this measure predicted ERP correlates of successful lexical prediction during discourse comprehension. 1/f neural noise across two different language tasks revealed high within-subject correlations, indicating that this measure can provide a reliable index of individualized patterns of neural activation. In addition to age, 1/f noise was a significant predictor of N400 effects of successful lexical prediction; however, noise did not mediate age-related declines in other ERP effects. We discuss broader implications of these findings for theories of predictive processing, as well as potential applications of 1/f noise across research populations.
• Karimi, H., Swaab, T.Y., & Ferreira, F.  (2018). Electrophysiological Evidence for an Independent Effect of Memory Retrieval on Referential Processing. Journal of Memory and Language, 102, 68-82 DOI: 10.1016/j.jml.2018.05.003
  • Abstract: In this study, we show that the difficulty of re-activating and retrieving the representations of potential referents from memory (retrieval difficulty) influences referential processing, and that this effect is independent of the number of potential referents for a pronoun or the probability of possible referential interpretations (referential coherence). In two experiments, we varied retrieval difficulty by manipulating whether two referential candidates were modified by extra semantic information or not, creating representationally rich (modified) or bare (unmodified) referential candidates, respectively, and we measured event-related brain potentials (ERPs) on following pronouns. We observed a sustained frontal negative shift (the Nref effect) on pronouns following bare, and therefore difficult-to-retrieve, referential candidates relative to those following representationally rich candidates, regardless of the ambiguity of pronouns and the probability of either referential interpretation. Since referential coherence was held constant across the conditions, the results suggest that retrieval difficulty affects referential processing independently of coherence. We discuss the implications for memory-based theories of language processing.
• Brothers, T., Swaab, T.Y., & Traxler, M.J., (2017). Goals and strategies influence lexical prediction during sentence comprehension. Journal of Memory and Language, 93, 203-216. DOI: 10.1016/j.jml.2016.10.002
  • Abstract: Predictive processing is a critical component of language comprehension, but exactly how and why comprehenders generate lexical predictions remains to be determined. Here, we present two experiments suggesting that lexical prediction is influenced by top-down comprehension strategies, and that lexical predictions are not always generated automatically as a function of the preceding context. In Experiment 1 (N = 24), participants read predictable and unpredictable sentence-final words while EEG was recorded from the scalp. When comparing two different sets of task instructions, the neural effects of cloze probability were enhanced when predictive processing was emphasized. In Experiment 2 (N = 252), participants read predictable and unpredictable sentence continuations in a self-paced reading task, and the overall validity of predictive cues was manipulated across groups using a separate set of filler sentences. There was a linear relationship between the benefits of a constraining sentence context and the global validity of predictive cues. Critically, no reading time benefits were observed as prediction validity approached zero. These results provide important constraints for theories of anticipatory language processing, while calling into question prior assumptions about the automaticity of lexical prediction.
• Choi, W., Lowder, M.W., Ferreira, F., Swaab, T.Y. &  Henderson, J.M.  (2017). Effects of word predictability and preview lexicality on eye movements during reading:  A comparison between young and older adults. Psychology and Aging, 32(3), 232-242. DOI: 10.1037/pag0000160
  • Abstract: Previous eye-tracking research has characterized older adults’ reading patterns as “risky,” arguing that compared to young adults, older adults skip more words, have longer saccades, and are more likely to regress to previous portions of the text. In the present eye-tracking study, we reexamined the claim that older adults adopt a risky reading strategy, utilizing the boundary paradigm to manipulate parafoveal preview and contextual predictability of a target word. Results showed that older adults had longer fixation durations compared to young adults; however, there were no age differences in skipping rates, saccade length, or proportion of regressions. In addition, readers showed higher skipping rates of the target word if the preview string was a word than if it was a nonword, regardless of age. Finally, the effect of predictability in reading times on the target word was larger for older adults than for young adults. These results suggest that older adults’ reading strategies are not as risky as was previously claimed. Instead, we propose that older adults can effectively combine top-down information from the sentence context with bottom-up information from the parafovea to optimize their reading strategies.
• Boudewyn, M.A., Carter, C.S., Long, D.L., Traxler, M.J., Lesh, T.A., Mangun, G.R., & Swaab, T.Y. (2017). Language Context Processing Deficits in Schizophrenia: the Role of Attentional Engagement. Neuropsychologia, 96, 262-273. DOI:10.1016/j.neuropsychologia.2017.01.024
  • Abstract: Individuals with schizophrenia exhibit problems in language comprehension that are most evident during discourse processing. We hypothesized that deficits in cognitive control contribute to these comprehension deficits during discourse processing, and investigated the underlying cognitive-neural mechanisms using EEG (alpha power) and ERPs (N400). N400 amplitudes to globally supported or unsupported target words near the end of stories were used to index sensitivity to previous context. ERPs showed reduced sensitivity to context in patients versus controls. EEG alpha-band activity was used to index attentional engagement while participants listened to the stories. We found that context effects varied with attentional engagement in both groups, as well as with negative symptom severity in patients. Both groups demonstrated trial-to-trial fluctuations in alpha. Relatively high alpha power was associated with compromised discourse processing in participants with schizophrenia when it occurred during any early portion of the story. In contrast, discourse processing was only compromised in controls when alpha was relatively high for longer segments of the stories. Our results indicate that shifts in attention from the story context may be more detrimental to discourse processing for participants with schizophrenia than for controls, most likely due to an impaired ability to benefit from global context.
• Li X, Zhang Y, Xia J, Swaab TY. (2017). Internal mechanisms underlying anticipatory language processing: Evidence from event-related-potentials and neural oscillations. Neuropsychologia, 102, 70-81.DOI: 10.1016/j.neuropsychologia.2017.05.017
  • Abstract: Although numerous studies have demonstrated that the language processing system can predict upcoming content during comprehension, there is still no clear picture of the anticipatory stage of predictive processing. This electroencephalograph study examined the cognitive and neural oscillatory mechanisms underlying anticipatory processing during language comprehension, and the consequences of this prediction for bottom-up processing of predicted/unpredicted content. Participants read Mandarin Chinese sentences that were either strongly or weakly constraining and that contained critical nouns that were congruent or incongruent with the sentence contexts. We examined the effects of semantic predictability on anticipatory processing prior to the onset of the critical nouns and on integration of the critical nouns. The results revealed that, at the integration stage, the strong-constraint condition (compared to the weak-constraint condition) elicited a reduced N400 and reduced theta activity (4–7 Hz) for the congruent nouns, but induced beta (13–18 Hz) and theta (4–7 Hz) power decreases for the incongruent nouns, indicating benefits of confirmed predictions and potential costs of disconfirmed predictions. More importantly, at the anticipatory stage, the strongly constraining context elicited an enhanced sustained anterior negativity and beta power decrease (19–25 Hz), which indicates that strong prediction places a higher processing load on the anticipatory stage of processing. The differences (in the ease of processing and the underlying neural oscillatory activities) between anticipatory and integration stages of lexical processing were discussed with regard to predictive processing models.
• Hoversten, L.J., Brothers, T., Swaab, T.Y., & Traxler, M.J. (2017). Early processing of orthographic language membership information in bilingual visual word recognition: Evidence from ERPs. Neuropsychologia, 103, 183-190 DOI: 10.1016/j.neuropsychologia.2017.07.026
  • Abstract: For successful language comprehension, bilinguals often must exert top-down control to access and select lexical representations within a single language. These control processes may critically depend on identification of the language to which a word belongs, but it is currently unclear when different sources of such language membership information become available during word recognition. In the present study, we used event-related potentials to investigate the time course of influence of orthographic language membership cues. Using an oddball detection paradigm, we observed early neural effects of orthographic bias (Spanish vs. English orthography) that preceded effects of lexicality (word vs. pseudoword). This early orthographic pop-out effect was observed for both words and pseudowords, suggesting that this cue is available prior to full lexical access. We discuss the role of orthographic bias for models of bilingual word recognition and its potential role in the suppression of nontarget lexical information.
• Kappenman, E. S., Luck, S. J., Kring, A. M., Lesh, T. A., Mangun, G. R., Niendam, T., Ragland, J. D., Ranganath, C., Solomon, M., Swaab, T. Y., & Carter, C. S. (2016). Electrophysiological evidence for impaired control of motor output in schizophrenia. Cerebral Cortex, 26 (5), 1891-1899. DOI:10.1093/cercor/bhu329
  • Previous research has demonstrated pervasive deficits in response-related processing in people with schizophrenia (PSZ). The present study used behavioral measures and event-related potentials (ERPs) to test the hypothesis that schizophrenia involves specific impairment in the ability to exert control over response-related processing. Twenty-two PSZ and 22 matched control participants completed a choice response task in counterbalanced testing sessions that emphasized only accuracy (the unspeeded condition) or emphasized speed and accuracy equally (the speeded condition). Control participants successfully modulated behavioral and ERP indices of response-related processing under speed pressure, as evidenced by faster and less variable reaction times (RTs) and an earlier onset and increased amplitude lateralized readiness potential (LRP). By contrast, PSZ were unable to improve RT speed or variability or to modulate the LRP under speed pressure, despite showing a decrease in accuracy. Notably, response-related deficits in PSZ emerged only in the speeded condition; behavioral and ERP measures did not differ between groups in the unspeeded condition. Together, these results indicate that impairment in the ability to exert control over response-related processing may underlie response-related deficits in schizophrenia.
• Brothers, T., Swaab, T.Y., and Traxler, M. (2015). Effect of prediction and contextual support on lexical processing: Prediction takes precedence. Cognition, 136, 135–149. DOI: 10.1016/j.cognition.2014.10.017
  • Abstract: Readers may use contextual information to anticipate and pre-activate specific lexical items during reading. However, prior studies have not clearly dissociated the effects of accurate lexical prediction from other forms of contextual facilitation such as plausibility or semantic priming. In this study, we measured electrophysiological responses to predicted and unpredicted target words in passages providing varying levels of contextual support. This method was used to isolate the neural effects of prediction from other potential contextual influences on lexical processing. While both prediction and discourse context influenced ERP amplitudes within the time range of the N400, the effects of prediction occurred much more rapidly, preceding contextual facilitation by approximately 100 ms. In addition, a frontal, post-N400 positivity (PNP) was modulated by both prediction accuracy and the overall plausibility of the preceding passage. These results suggest a unique temporal primacy for prediction in facilitating lexical access. They also suggest that the frontal PNP may index the costs of revising discourse representations following an incorrect lexical prediction.
• Hoversten, L, Brothers, T., Swaab, T.Y., and Traxler, M. (2015). Language membership identification precedes semantic access: Suppression during bilingual word recognition. Journal of Cognitive Neuroscience, 27(11), 2108-16. DOI: 10.1162/jocn_a_00844
  • Abstract: Previous research suggests that bilingual comprehenders access lexical representations of words in both languages nonselectively. However, it is unclear whether global language suppression plays a role in guiding attention to target language representations during ongoing lexico-semantic processing. To help clarify this issue, this study examined the relative timing of language membership and meaning activation during visual word recognition. Spanish–English bilinguals performed simultaneous semantic and language membership classification tasks on single words during EEG recording. Go/no-go ERP latencies provided evidence that language membership information was accessed before semantic information. Furthermore, N400 frequency effects indicated that the depth of processing of words in the nontarget language was reduced compared to the target language. These results suggest that the bilingual brain can rapidly identify the language to which a word belongs and subsequently use this information to selectively modulate the degree of processing in each language accordingly.
• Boudewyn, M.A., Long, D.L., Traxler, M.J., Lesh, T., Dave, S., Mangun, G.R., Carter, C.S. & Swaab, T.Y.  (2015). Sensitivity to Referential Ambiguity in Discourse: the Role of Attention, Working Memory and Verbal Ability. Journal of Cognitive Neuroscience, 27(12), 2309-2323. DOI: 10.1162/jocn_a_00837
  • Abstract: The establishment of reference is essential to language comprehension. The goal of this study was to examine listeners' sensitivity to referential ambiguity as a function of individual variation in attention, working memory capacity, and verbal ability. Participants listened to stories in which two entities were introduced that were either very similar (e.g., two oaks) or less similar (e.g., one oak and one elm). The manipulation rendered an anaphor in a subsequent sentence (e.g., oak) ambiguous or unambiguous. EEG was recorded as listeners comprehended the story, after which participants completed tasks to assess working memory, verbal ability, and the ability to use context in task performance. Power in the alpha and theta frequency bands when listeners received critical information about the discourse entities (e.g., oaks) was used to index attention and the involvement of the working memory system in processing the entities. These measures were then used to predict an ERP component that is sensitive to referential ambiguity, the Nref, which was recorded when listeners received the anaphor. Nref amplitude at the anaphor was predicted by alpha power during the earlier critical sentence: Individuals with increased alpha power in ambiguous compared with unambiguous stories were less sensitive to the anaphor's ambiguity. Verbal ability was also predictive of greater sensitivity to referential ambiguity. Finally, increased theta power in the ambiguous compared with unambiguous condition was associated with higher working-memory span. These results highlight the role of attention and working memory in referential processing during listening comprehension.
• Boudewyn, M.A., Long, D.L. & Swaab, T.Y. (2015). Graded Expectations: Predictive Processing and the Adjustment of Expectations during Spoken Language Comprehension. Cognitive, Affective and Behavioral Neuroscience. Cognitive, Affective, & Behavioral Neuroscience, 15 (3), 607-624. DOI: 10.3758/s13415-015-0340-0
  • Abstract: The goal of this study was to investigate the use of the local and global contexts for incoming words during listening comprehension. Local context was manipulated by presenting a target noun (e.g., “cake,” “veggies”) that was preceded by a word that described a prototypical or atypical feature of the noun (e.g., “sweet,” “healthy”). Global context was manipulated by presenting the noun in a scenario that was consistent or inconsistent with the critical noun (e.g., a birthday party). Event-related potentials (ERPs) were examined at the feature word and at the critical noun. An N400 effect was found at the feature word, reflecting the effect of compatibility with the global context. Global predictability and the local feature word consistency interacted at the critical noun: A larger N200 was found to nouns that mismatched predictions when the context was maximally constraining, relative to nouns in the other conditions. A graded N400 response was observed at the critical noun, modulated by global predictability and feature consistency. Finally, post-N400 positivity effects of context updating were observed to nouns that were supported by one contextual cue (global/local) but were unsupported by the other. These results indicate that (1) incoming words that are compatible with context-based expectations receive a processing benefit; (2) when the context is sufficiently constraining, specific lexical items may be activated; and (3) listeners dynamically adjust their expectations when input is inconsistent with their predictions, provided that the inconsistency has some level of support from either the global or the local context.
• Ragland, J.D., Ranganath, C., Phillips, J., Boudewyn, M.A., Kring, A.M., Lesh, T.A., Long, D.L., Luck, S.J., Niendam, T.A., Solomon, M., Swaab, T.Y., Carter, C.S. (2015). Cognitive Control of Episodic Memory in Schizophrenia: Differential Role of Dorsolateral and Ventrolateral Prefrontal Cortex. Frontiers in Human Neuroscience, 2015, 9:604. DOI: 10.3389/fnhum.2015.00604
  • Abstract: Dorsal (DLPFC) and ventral (VLPFC) subregions in lateral prefrontal cortex play distinct roles in episodic memory, and both are implicated in schizophrenia. We test the hypothesis that schizophrenia differentially impairs DLPFC versus VLPFC control of episodic encoding. Methods: Cognitive control was manipulated by requiring participants to encode targets and avoid encoding non-targets based upon stimulus properties of test stimuli. The more automatic encoding response (target versus non-target) was predicted to engage VLPFC in both groups. Conversely, having to overcome the prepotent encoding response (non-targets versus targets) was predicted to produce greater DLPFC activation in controls than in patients. Encoding occurred during event-related fMRI in a sample of 21 individuals with schizophrenia and 30 healthy participants. Scanning was followed by recognition testing outside the scanner. Results: Patients were less successful differentially remembering target versus non-target stimuli, and retrieval difficulties correlated with more severe disorganized symptoms. As predicted, the target versus non-target contrast activated the VLPFC and correlated with retrieval success in both groups. Conversely, the non-target versus target contrast produced greater DLPFC activation in controls than in patients, and DLPFC activation correlated with performance only in controls. Conclusion: Individuals with schizophrenia can successfully engage the VLPFC to provide control over semantic encoding of individual items, but are specifically impaired at engaging the DLPFC to main context for task-appropriate encoding and thereby generate improved memory for target versus non-target items. This extends previous cognitive control models based on response selection tasks to the memory domain.
• Johns, C., Gordon, P.C., Long, D.L. & Swaab, T. Y. (2014). Memory availability and referential access. Language, Cognition and Neuroscience, 29(1), 60-87 DOI: 10.1080/01690965.2012.733014
  • Abstract: Most theories of coreference specify linguistic factors that modulate antecedent accessibility in memory; however, whether nonlinguistic factors also affect coreferential access is unknown. Here we examined the impact of a nonlinguistic generation task (letter-transposition) on the repeated-name penalty, a processing difficulty observed when coreferential repeated names refer to syntactically prominent (and thus more accessible) antecedents. In Experiment 1, generation improved online (event-related potentials) and offline (recognition memory) accessibility of names in word lists. In Experiment 2, we manipulated generation and syntactic prominence of antecedent names in sentences; both improved online and offline accessibility, but only syntactic prominence elicited a repeated-name penalty. Our results have three important implications: (1) the form of a referential expression interacts with an antecedent's status in the discourse model during coreference; (2) availability in memory and referential accessibility are separable; and (3) theories of coreference must better integrate known properties of the human memory system.
• Boudewyn, M.A., Zirnstein, M., Swaab, T.Y., & Traxler, M.J. (2014). Priming Prepositional Phrase Attachment: Evidence from Eye-tracking and ERPs. Quarterly Journal of Experimental Psychology, 467(3), 424-54. DOI: 10.1080/17470218.2013.815237
  • Abstract: Three syntactic-priming experiments investigated the effect of structurally similar or dissimilar prime sentences on the processing of target sentences, using eye tracking (Experiment 1) and event-related potentials (ERPs) (Experiments 2 and 3) All three experiments tested readers' response to sentences containing a temporary syntactic ambiguity. The ambiguity occurred because a prepositional phrase modifier (PP-modifier) could attach either to a preceding verb or to a preceding noun. Previous experiments have established that (a) noun-modifying expressions are harder to process than verb-modifying expressions (when test sentences are presented in isolation); and (b) for other kinds of sentences, processing a structurally similar prime sentence can facilitate processing a target sentence. The experiments reported here were designed to determine whether a structurally similar prime could facilitate processing of noun-attached modifiers and whether such facilitation reflected syntactic-structure-building or semantic processes. These findings have implications for accounts of structural priming during online comprehension and for accounts of syntactic representation and processing in comprehension.
• Minzenberg, M., Gomez, G, C. Yoon, J.H., Swaab, T.Y., Carter, C. S. (2014). Disrupted Action Monitoring in Recent-Onset Psychosis Patients with Schizophrenia and Bipolar Disorder. Psychiatry Research: Neuroimaging, 221 (1), 114-121 DOI: 10.1016/j.pscychresns.2013.11.003
  • Abstract: Schizophrenia patients experience cognitive control disturbances, manifest in altered neural signatures during action monitoring. It remains unclear whether error- and conflict-monitoring disturbances co-occur, and whether they are observed in recent-onset psychosis patients with schizophrenia or bipolar disorder. We tested electrophysiological measures of action monitoring in these patients. Seventy-three schizophrenia patients (SZ), 26 bipolar disorder type I patients (BP), each within one year of psychosis onset, and 54 healthy control subjects (HC) underwent EEG during Stroop task performance. In the trial-averaged EEG at three midline scalp electrodes, the error-related negativity (ERN), error positivity (Pe) and conflict-related N450 were measured. Compared to HC (1) SZ exhibited an attenuated ERN and N450, and Pe unchanged and (2) BP exhibited an attenuated ERN but normal Pe and N450. Between patient groups, SZ showed an attenuated N450; ERN and Pe were not significantly different. A small (n=10) SZ subgroup that was not receiving antipsychotic medication showed normal ERPs. Altered error- and conflict-monitoring occur together in the first-episode schizophrenia patients, and these measures are comparable in patients with the first-episode bipolar disorder. Antipsychotic medication may be associated with altered measures of error-monitoring in schizophrenia.
• Tooley, K.M., Swaab, T.Y., Boudewyn, M.A., Zirnstein, M. & Traxler, M.J. (2013). Evidence for Priming across Intervening Sentences during Online Sentence Comprehension. Language and Cognitive Processes, 129(3), 289-311 DOI: 10.1080/01690965.2013.770892
  • Abstract: Three experiments investigated factors contributing to syntactic priming during on-line comprehension. In all of the experiments, a prime sentence containing a reduced relative clause was presented prior to a target sentence that contained the same structure. Previous studies have shown that people respond more quickly when a syntactically related prime sentence immediately precedes a target. In the current study, ERP and eye-tracking measures were used to assess whether priming in sentence comprehension persists when one or more unrelated filler sentences appear between the prime and the target. In experiment 1, a reduced P600 was found to target sentences both when there were no intervening unrelated fillers, and when there was one unrelated filler between the prime and the target. Thus, processing the prime sentence facilitated processing of the syntactic form of the target sentence. In experiments 2 and 3, eye-tracking experiments showed that target sentence processing was facilitated when three filler sentences intervened between the prime and the target. These experiments show that priming effects in comprehension can be observed when unrelated material appears after a prime sentence and before the target. We interpret the results with respect to residual activation and implicit learning accounts of priming.
• Vergara-Martinez, M., Perea, M. ,Gómez, P. & Swaab, T.Y. (2013). ERP correlates of letter identity and letter position are modulated by lexical frequency. Brain and Language, 125, 11-27 DOI: 10.1016/j.bandl.2012.12.009
  • Abstract: The encoding of letter position is a key aspect in all recently proposed models of visual-word recognition. We analyzed the impact of lexical frequency on letter position assignment by examining the temporal dynamics of lexical activation induced by pseudowords extracted from words of different frequencies. For each word (e.g., BRIDGE), we created two pseudowords: A transposed-letter (TL: BRIGDE) and a replaced-letter pseudoword (RL: BRITGE). ERPs were recorded while participants read words and pseudowords in two tasks: Semantic categorization (Experiment 1) and lexical decision (Experiment 2). For high-frequency stimuli, similar ERPs were obtained for words and TL-pseudowords, but the N400 component to words was reduced relative to RL-pseudowords, indicating less lexical/semantic activation. In contrast, TL- and RL-pseudowords created from low-frequency stimuli elicited similar ERPs. Behavioral responses in the lexical decision task paralleled this asymmetry. The present findings impose constraints on computational and neural models of visual-word recognition.
• Boudewyn, M.A., Long, D.L., & Swaab, T.Y. (2013). Effects of working memory span on processing of lexical associations and congruence in spoken discourse. Frontiers in Psychology, 4 (60), 1-16 DOI:doi.org/10.3389/fpsyg.2013.00060
  • Abstract: The goal of this study was to determine whether variability in working memory (WM) capacity and cognitive control affects the processing of global discourse congruence and local associations among words when participants listened to short discourse passages. The final, critical word of each passage was either associated or unassociated with a preceding prime word (e.g., “He was not prepared for the fame and fortune/praise”). These critical words were also either congruent or incongruent with respect to the preceding discourse context [e.g., a context in which a prestigious prize was won (congruent) or in which the protagonist had been arrested (incongruent)]. We used multiple regression to assess the unique contribution of suppression ability (our measure of cognitive control) and WM capacity on the amplitude of individual N400 effects of congruence and association. Our measure of suppression ability did not predict the size of the N400 effects of association or congruence. However, as expected, the results showed that high WM capacity individuals were less sensitive to the presence of lexical associations (showed smaller N400 association effects). Furthermore, differences in WM capacity were related to differences in the topographic distribution of the N400 effects of discourse congruence. The topographic differences in the global congruence effects indicate differences in the underlying neural generators of the N400 effects, as a function of WM. This suggests additional, or at a minimum, distinct, processing on the part of higher capacity individuals when tasked with integrating incoming words into the developing discourse representation.
• Swaab, T.Y., Boudewyn, M.A., Long, D.L., Luck, S.L., Kring, A., Ragland, D., Ranganath, C., Lesh, T., Niendam, T.A., Solomon, M. Mangun, G.R. & Carter, C. (2013). Spared and Impaired Spoken Discourse Processing in Schizophrenia: Effects of Local and Global Language Context. Journal of Neuroscience, 33(39), 15578-87 DOI:10.1523/JNEUROSCI.0965-13.2013
  • Abstract: Individuals with schizophrenia are impaired in a broad range of cognitive functions, including impairments in the controlled maintenance of context-relevant information. In this study, we used ERPs in human subjects to examine whether impairments in the controlled maintenance of spoken discourse context in schizophrenia lead to overreliance on local associations among the meanings of individual words. Healthy controls (n = 22) and patients (n = 22) listened to short stories in which we manipulated global discourse congruence and local priming. The target word in the last sentence of each story was globally congruent or incongruent and locally associated or unassociated. ERP local association effects did not significantly differ between control participants and schizophrenia patients. However, in contrast to controls, patients only showed effects of discourse congruence when targets were primed by a word in the local context. When patients had to use discourse context in the absence of local priming, they showed impaired brain responses to the target. Our findings indicate that schizophrenia patients are impaired during discourse comprehension when demands on controlled maintenance of context are high. We further found that ERP measures of increased reliance on local priming predicted reduced social functioning, suggesting that alterations in the neural mechanisms underlying discourse comprehension have functional consequences in the illness.
• Swaab, T.Y. (2013). Language (Chapter 11). (2014). In: Gazzaniga, M.S., R., Ivry and G.R. Mangun, Cognitive Neuroscience: The Biology of the Mind. (4th Edition). W.W. Norton Pub.: New York (Textbook).
• Swaab, T.Y., Ledoux, K., Camblin, C.C., & Boudewyn, M.A. (2012) Language related ERP components. (Book Chapter). In: Luck, S. J. & Kappenman, E.S. (Eds.), pp 397-440. Oxford Handbook of Event-Related Potential Components. New York: Oxford University Press.  DOI: 10.1093/oxfordhb/9780195374148.013.0197
  • Abstract: Understanding the processes that permit us to extract meaning from spoken or written linguistic input requires elucidating how, when, and where in the brain sentences and stories, syllables and words are analyzed. Because human language is a cognitive function that is not readily investigated using neuroscience approaches in animal models, this task presents special challenges. In this chapter, we describe how event-related potentials (ERPs) have contributed to the understanding of language processes as they unfold in real-time. We will provide an overview of the many ERPs that have been used in language research, and will discuss the main models of what these ERPs reflect in terms of linguistic and neural processes. In addition, using examples from the literature, we will illustrate how ERPs can be used to study language comprehension, and will also outline methodological issues that are specific to using ERPs in language research.
• Boudewyn, M.A., Carter, C. & Swaab, T.Y. (2012). Cognitive Control and Discourse Comprehension in Schizophrenia. Schizophrenia Research and Treatment, 1- 7. doi:10.1155/2012/484502
  • Abstract: Cognitive deficits across a wide range of domains have been consistently observed in schizophrenia and are linked to poor functional outcome (Green, 1996; Carter, 2006). Language abnormalities are among the most salient and include disorganized speech as well as deficits in comprehension. In this review, we aim to evaluate impairments of language processing in schizophrenia in relation to a domain-general control deficit. We first provide an overview of language comprehension in the healthy human brain, stressing the role of cognitive control processes, especially during discourse comprehension. We then discuss cognitive control deficits in schizophrenia, before turning to evidence suggesting that schizophrenia patients are particularly impaired at processing meaningful discourse as a result of deficits in control functions. We conclude that domain-general control mechanisms are impaired in schizophrenia and that during language comprehension this is most likely to result in difficulties during the processing of discourse-level context, which involves integrating and maintaining multiple levels of meaning. Finally, we predict that language comprehension in schizophrenia patients will be most impaired during discourse processing. We further suggest that discourse comprehension problems in schizophrenia might be mitigated when conflicting information is absent and strong relations amongst individual words are present in the discourse context."There is no "centre of Speech" in the brain any more than there is a faculty of Speech in the mind.The entire brain, more or less, is at work in a man who uses language"William JamesFrom The Principles of Psychology, 1890"The mind in dementia praecox is like an orchestra without a conductor"Kraepelin, 1919.
• Qiu, L., Swaab, T.Y., Chen, H., & Wang, S. (2012). The Role of Gender Information in Pronoun Resolution: Evidence from Chinese. PloS one. 7(5): e36156. doi:10.1371/journal.pone.0036156 DOI: 10.1371/journal.pone.0036156
  • Abstract: Although previous studies have consistently demonstrated that gender information is used to resolve pronouns, the mechanisms underlying the use of gender information continue to be controversial. The present study used event-related potentials (ERPs) to investigate whether working memory modulates the effect of gender information on pronoun resolution. The critical pronoun agreed or disagreed with its antecedent in gender. Moreover, the distance between a pronoun and its antecedent was varied to assess the influence of working memory. Compared with the congruent pronouns, the incongruent pronouns elicited an N400 effect in the short distance condition and a P600 effect in the long distance condition. The results suggest that the effect of gender information on pronoun comprehension is modulated by working memory.
• Vergara-Martínez, M. & Swaab, T.Y. (2012). Orthographic neighborhood effects as a function of word frequency: An Event-Related Potential study. Psychophysiology, 49, 1277–1289 DOI:10.1111/j.1469-8986.2012.01410.x
  • Abstract: The present study assessed the mechanisms and time course by which orthographic neighborhood size (ON) influences visual word recognition. ERPs were recorded to words that varied in ON and in word frequency while participants performed a semantic categorization task. ON was measured with the Orthographic Levenshtein Distance (OLD20), a richer metric of orthographic similarity than the traditional Coltheart's N metric. The N400 effects of ON (260–500 ms) were larger and showed a different scalp distribution for low than for high frequency words, which is consistent with proposals that suggest lateral inhibitory mechanisms at a lexical level. The ERP ON effects had a shorter duration and different scalp distribution than the effects of word frequency (mainly observed between 380–600 ms) suggesting a transient activation of the subset of orthographically similar words in the lexical network compared to the impact of properties of the single words.
• Boudewyn, M.A., Long, D.L., & Swaab, T.Y. (2012). Cognitive Control Influences the use of Meaning Relations during Spoken Sentence Comprehension. Neuropsychologia, 50, 2659-2668 DOI: 10.1016/j.neuropsychologia.2012.07.019
  • The aim of this study was to investigate individual differences in the influence of lexical association on word recognition during auditory sentence processing. Lexical associations among individual words (e.g. salt and pepper) represent one type of semantic information that is available during the processing of words in context. We predicted that individuals would vary in their sensitivity to this type of local context as a function of suppression ability and working-memory capacity. Lexical association was manipulated in auditory sentence contexts, and multiple regression analyses were employed to examine the relation between individuals’ brain responses to meaning relations in sentences and measures of working-memory capacity, cognitive control and vocabulary. Lexical association influenced the processing of words that were embedded in sentences and also showed a great deal of individual variability. Specifically, suppression ability emerged as a significant predictor of sensitivity to lexical association, such that individuals who performed poorly on our measure of suppression ability (the Stroop task), compared to those who performed well, showed larger N400 effects of lexical association.
• Boudewyn, M.A., Gordon, P.C., Long, D., Polse, L. & Swaab, T.Y. (2011). Does discourse congruence influence spoken language comprehension before lexical association? Evidence from event-related potentials. Language and Cognitive Processes.          DOI: 10.1080/01690965.2011.577980
  • Abstract: The goal of this study was to examine how lexical association and discourse congruence affect the time course of processing incoming words in spoken discourse. In an event-related potential (ERP) norming study, we presented prime-target pairs in the absence of a sentence context to obtain a baseline measure of lexical priming. We observed a typical N400 effect when participants heard critical associated and unassociated target words in word pairs. In a subsequent experiment, we presented the same word pairs in spoken discourse contexts. Target words were always consistent with the local sentence context, but were congruent or not with the global discourse (e.g., “Luckily Ben had picked up some salt and pepper/basil,” preceded by a context in which Ben was preparing marinara sauce (congruent) or dealing with an icy walkway (incongruent). Event-related potential effects of global discourse congruence preceded those of local lexical association, suggesting an early influence of the global discourse representation on lexical processing, even in locally congruent contexts. Furthermore, effects of lexical association occurred earlier in the congruent than incongruent condition. These results differ from those that have been obtained in studies of reading, suggesting that the effects may be unique to spoken word recognition.
• Nakano, H., Saron, C., & Swaab, T.Y. (2010). Speech and Span: Working memory capacity impacts the use of animacy but not of world knowledge during spoken sentence comprehension. Journal of Cognitive Neuroscience, 22 (12), 2886–2898  DOI: 10.1162/jocn.2009.21400
  • Abstract: We present results from a study demonstrating that high- and low-span listeners show qualitatively different brain responses when comprehending simple active sentences. Participants listened to naturally produced sentences in three conditions in which the plausibility of thematic relations was manipulated, for instance: The dog(1)/The poet(2)/The box(3) is biting the mailman. Event-related potentials were recorded to the first noun, the verb, and the second noun in all three conditions. In (2), the thematic relations between the words in the sentence are less expected given our world knowledge, and this resulted in an N400 effect of semantic processing difficulty to the second noun for both high- and low-span subjects. In (3), the inanimate first noun cannot be the agent of the verb. Only high-span subjects showed an effect of animacy on the sentence-initial nouns, evident from a larger anterior negative shift to inanimate than animate nouns. Furthermore, to the thematically violated verbs (3), low-span subjects showed an N400, whereas high-span subjects generated a P600. We suggest that this P600 effect to the thematically violated verb may be related to processing costs resulting from a conflict between the provisional thematic roles assigned as a function of the inanimate sentence-initial noun, and the actual (animate) agent required by the verb. We further argue that low-span subjects lag behind those with high span in their use of animacy, but not real-world knowledge in the on-line computation of thematic roles in spoken language comprehension.
• Tooley, K., Traxler, M. & Swaab, T.Y. (2009). Electrophysiological and Behavioral Evidence of Syntactic Priming in Sentence Comprehension. Journal of Experimental Psychology: Language, Memory and Cognition, 35, 19-45. DOI: 10.1037/a0013984
  • Abstract: Event-related potentials and eye tracking were used to investigate the nature of priming effects in sentence comprehension. Participants read 2 sentences (a prime sentence and a target sentence), both of which had a difficult and ambiguous sentence structure. The prime and target sentences contained either the same verb or verbs that were very close in meaning. Priming effects were robust when the verb was repeated. In the event-related potential experiment, the amplitude of the P600 was reduced in target sentences that followed prime sentences with the same verb but not in prime sentences with a synonymous verb. In the eye-tracking experiment, total reading times on the disambiguating region were reduced when the targets followed prime sentences with the same verb but not when targets followed prime sentences with a synonymous verb. The fact that verb overlap greatly boosted priming effects in reduced relative sentences may indicate that verb argument structures play an important role in online parsing.
• Swaab, T.Y. (2009). Language (Chapter 10). In: Gazzaniga, M.S., R., Ivry and G.R. Mangun, Cognitive Neuroscience: The Biology of the Mind. (3rd Edition). W.W. Norton Pub.: New York (Textbook).
• Ledoux, K., Gordon, P.C., Camblin, C.C. & Swaab, T.Y (2007). Coreference and lexical repetition: Neural mechanisms of discourse integration. Memory and Cognition. 35 (4), 801-815 DOI: 10.3758/bf03193316
  • Abstract: The use of repeated expressions to establish coreference allows an investigation of the relationship between basic processes of word recognition and higher level language processes that involve the integration of information into a discourse model. In two experiments on reading, we used eye tracking and event-related potentials to examine whether repeated expressions that are coreferential within a local discourse context show the kind of repetition priming that is shown in lists of words. In both experiments, the effects of lexical repetition were modulated by the effects of local discourse context that arose from manipulations of the linguistic prominence of the antecedent of a coreferentially repeated name. These results are interpreted within the context of discourse prominence theory, which suggests that processes of coreferential interpretation interact with basic mechanisms of memory integration during the construction of a model.
• Diaz, M. & Swaab, T.Y. (2007). Electrophysiological differentiation of phonological and semantic integration in word and sentence contexts. Brain Research. 1146, 85-100 DOI: 10.1016/j.brainres.2006.07.034.
  • Abstract: During auditory language comprehension, listeners need to rapidly extract meaning from the continuous speech-stream. It is a matter of debate when and how contextual information constrains the activation of lexical representations in meaningful contexts. Electrophysiological studies of spoken language comprehension have identified an event-related potential (ERP) that was sensitive to phonological properties of speech, which was termed the phonological mismatch negativity (PMN). With the PMN, early lexical processing could potentially be distinguished from processes of semantic integration in spoken language comprehension. However, the sensitivity of the PMN to phonological processing per se has been questioned, and it has additionally been suggested that the “PMN” is not separable from the N400, an ERP that is sensitive to semantic aspects of the input. Here, we investigated whether or not a separable PMN exists and if it reflects purely phonological aspects of the speech input. In the present experiment, ERPs were recorded from healthy young adults (N = 24) while they listened to sentences and word lists, in which we manipulated semantic and phonological expectation and congruency of the final word. ERPs sensitive to phonological processing were elicited only when phonological expectancy was violated in lists of words, but not during normal sentential processing. This suggests a differential role of phonological processing in more or less meaningful contexts and indicates a very early influence of the overall context on lexical processing in sentences.
• Camblin C.C., Gordon, P.C. & Swaab, T.Y. (2007). The interplay of discourse congruence and lexical association during sentence processing: Evidence from ERPs and eye tracking. Journal of Memory and Language. 56, 103–128 DOI: 10.1016/j.jml.2006.07.005
  • Abstract: Five experiments used ERPs and eye tracking to determine the interplay of word-level and discourse-level information during sentence processing. Subjects read sentences that were locally congruent but whose congruence with discourse context was manipulated. Furthermore, critical words in the local sentence were preceded by a prime word that was associated or not. Violations of discourse congruence had early and lingering effects on ERP and eye-tracking measures. This indicates that discourse representations have a rapid effect on lexical semantic processing even in locally congruous texts. In contrast, effects of association were more malleable: Very early effects of associative priming were only robust when the discourse context was absent or not cohesive. Together these results suggest that the global discourse model quickly influences lexical processing in sentences, and that spreading activation from associative priming does not contribute to natural reading in discourse contexts.
• Ledoux, K., Traxler, M.J., & Swaab, T.Y. (2007). Syntactic Priming in Comprehension: Evidence from Event-Related Potentials. Psychological Science. 18, 135-143 DOI: 10.1111/j.1467-9280.2007.01863.x
  • Abstract: Syntactic priming is the facilitation of processing that occurs when a sentence has the same syntactic form as a preceding sentence. Such priming effects have been less consistently demonstrated in comprehension than in production, and those that have been reported have depended on the repetition of verbs across sentences. In an event-related potential experiment, subjects read target sentences containing reduced-relative clauses. Each was preceded by a sentence that contained the same verb and either a reduced-relative or a main-clause construction. Reduced-relative primes elicited a larger positivity than did main-clause primes. Reduced-relative targets that were preceded by a main-clause prime elicited a greater positivity than the same target sentences following a reduced-relative prime. In addition, syntactic priming effects were dissociated from effects of lexical repetition at the verb.
• Camblin, C.C., Ledoux, K, Boudewyn, M., Gordon, P.C., & Swaab, T.Y. (2007). When and How do Readers and Listeners establish Coreference with Repeated Names? Brain Research. 1146, 174-184. DOI: 10.1016/j.brainres.2006.07.033
  • Abstract: Previous research has shown that the process of establishing coreference with a repeated name can affect basic repetition priming. Specifically, repetition priming on some measures can be eliminated for repeated names that corefer with an entity that is prominent in the discourse model. However, the exact nature and timing of this modulating effect of discourse are not yet understood. Here, we present two ERP studies that further probe the nature of repeated name coreference by using naturally produced connected speech and fast-rate RSVP methods of presentation. With speech we found that repetition priming was eliminated for repeated names that coreferred with a prominent antecedent. In contrast, with fast-rate RSVP, we found a main effect of repetition that did not interact with sentence context. This indicates that the creation of a discourse model during comprehension can affect repetition priming, but the nature of this effect may depend on input speed.
• Ledoux, K., Camblin, C.C., Swaab, T.Y., & Gordon, P.C (2006). Reading words in discourse: The modulation of intralexical priming effects by message-level context. Behavioral and Cognitive Neuroscience Reviews, 5, 107-127 DOI: 10.1177/1534582306289573
  • Abstract: Repetition and semantic-associative priming effects have been demonstrated for words in nonstructured contexts (i.e., word pairs or lists of words) in numerous behavioral and electrophysiological studies. The processing of a word has thus been shown to benefit from the prior presentation of an identical or associated word in the absence of a constraining context. An examination of such priming effects for words that are embedded within a meaningful discourse context provides information about the interaction of different levels of linguistic analysis. This article reviews behavioral and electrophysiological research that has examined the processing of repeated and associated words in sentence and discourse contexts. It provides examples of the ways in which eye tracking and event-related potentials might be used to further explore priming effects in discourse. The modulation of lexical priming effects by discourse factors suggests the interaction of information at different levels in online language comprehension.
• Kaan, E., Wijnen, F., & Swaab, T.Y. (2004). Gapping: Electrophysical Evidence for Immediate Processing of “Missing” Verbs in Sentence Comprehension. Brain and Language, 89, 584-592.
  • Abstract: In the present study we use event related potentials (ERPs) to explore the time course of identification and resolution of verb gaps. ERPs were recorded while participants read sentences that contained a verb gap like Ron took/sanded the planks, and Bill Ø the hammer… Plausibility of the critical words (hammer) that followed the verb gap was manipulated. Relative to the plausible control (preceded by took), ERPs to the critical word in the implausible condition (preceded by sanded) showed an N400, followed by a positivity (P600). ERPs to determiners following gapped verbs showed a negativity between 100 and 300 ms, and a positivity between 300 and 500 ms compared to determiners in non-gapping constructions. These results suggest that the sentence processor recognizes a verb gap and reconstructs the verb information at the earliest possible occasion, and that this reconstruction process is different from the reconstruction of antecedents in other filler-gap constructions (e.g., WH gaps).
• Giesbrecht, B., Camblin, C.C., & Swaab, T.Y. (2004). Separable effects of semantic priming and imageability on word processing in human cortex. Cerebral Cortex, 14, 521-529.
  • Abstract: Understanding the neural representation of semantic concepts is at the core of understanding human knowledge and experience. Competing cognitive theories suggest that these neural representations are based on either a unitary semantic code or on multiple semantic codes. We contrasted these theories using event-related fMRI in a semantic priming study. Pairs of words were presented that were either semantically related or unrelated and were either high or low imageable. The unitary view predicts that there should be little or no difference between neural activity evoked by high and low imageable words when presented in a related context, but large differences in neural activity when there is an unrelated context. In contrast to this view, we provide evidence for functionally and anatomically separable effects of context and imageability in human cortex, suggesting that semantic knowledge consists of multiple representational codes.
• Swaab, T.Y., Camblin, C.C., & Gordon. P.C. (2004). Reversed lexical repetition effects in language processing. Journal of Cognitive Neuroscience, 16, 715-726.
  • Abstract: Effects of word repetition are extremely robust, but can these effects be modulated by discourse context? We examined this in an ERP experiment that tested coreferential processing (when two expressions refer to the same person) with repeated names. ERPs were measured to repeated names and pronoun controls in two conditions: (1) In the prominent condition the repeated name or pronoun coreferred with the subject of the preceding sentence and was therefore prominent in the preceding discourse (e.g., “John went to the store after John/he …”); (2) in the nonprominent condition the repeated name or pronoun coreferred with a name that was embedded in a conjoined noun phrase, and was therefore nonprominent (e.g., “John and Mary went to the store after John/he …”). Relative to the prominent condition, the nonprominent condition always contained two extra words (e.g., “and Mary”), and the repetition lag was therefore smaller in the prominent condition. Typically, effects of repetition are larger with smaller lags. Nevertheless, the amplitude of the N400 was reduced to a coreferentially repeated name when the antecedent was nonprominent as compared to when it was prominent. No such difference was observed for the pronoun controls. Because the N400 effect reflects difficulties in lexical integration, this shows that the difficulty of achieving coreference with a name increased with the prominence of the referent. This finding is the reverse of repetition lag effects on N400 previously found with word lists, and shows that language context can override general memory mechanisms.
• Gordon, P.C., Camblin, C.C. & Swaab, T.Y . (2004). On-line measures of coreferential processing. In: M. Carreiras & C. Clifton (Eds.), The On-line Study of Sentence Comprehension: Eyetracking, ERP and Beyond, New York, NY: Psychology Press.
• Kaan, E. & Swaab, T.Y. (2003). Repair, revision and complexity in syntactic analysis: An electrophysiological differentiation. Journal of Cognitive Neuroscience, 15, 98-110.
  • Abstract: One of the core aspects of human sentence processing is the ability to detect errors and to recover from erroneous analysis through revision of ambiguous sentences and repair of ungrammatical sentences. In the present study, we used event-related potentials (ERPs) to help identify the nature of these processes by directly comparing ERPs to complex ambiguous sentence structures with and without grammatical violations, and to simpler unambiguous sentence structures with and without grammatical violations. In ambiguous sentences, preference of syntactic analysis was manipulated such that in one condition, the structures agreed with the preferred analysis, and in another condition, a nonpreferred but syntactically correct analysis (garden path) was imposed. Nonpreferred ambiguous structures require revision, whereas ungrammatical structures require repair. We found that distinct ERPs reflected different characteristics of syntactic processing. Specifically, our results are consistent with the idea that a positivity with a posterior distribution across the scalp (posterior P600) is an index of syntactic processing difficulty, including repair and revision, and that a frontally distributed positivity (frontal P600) is related to ambiguity resolution and/ or to an increase in discourse level complexity.
• Swaab, T.Y., Brown, C.M., & Hagoort, P. (2003). Understanding words in sentence contexts: the time course of ambiguity resolution. Brain and Language, 86, 326-343.
  • Abstract: Spoken language comprehension requires rapid integration of information from multiple linguistic sources. In the present study we addressed the temporal aspects of this integration process by focusing on the time course of the selection of the appropriate meaning of lexical ambiguities (“bank”) in sentence contexts. Successful selection of the contextually appropriate meaning of the ambiguous word is dependent upon the rapid binding of the contextual information in the sentence to the appropriate meaning of the ambiguity. We used the N400 to identify the time course of this binding process. The N400 was measured to target words that followed three types of context sentences. In the concordant context, the sentence biased the meaning of the sentence-final ambiguous word so that it was related to the target. In the discordant context, the sentence context biased the meaning so that it was not related to the target. In the unrelated control condition, the sentences ended in an unambiguous noun that was unrelated to the target. Half of the concordant sentences biased the dominant meaning, and the other half biased the subordinate meaning of the sentence-final ambiguous words. The ISI between onset of the target word and offset of the sentence-final word of the context sentence was 100 ms in one version of the experiment, and 1250 ms in the second version. We found that (i) the lexically dominant meaning is always partly activated, independent of context, (ii) initially both dominant and subordinate meaning are (partly) activated, which suggests that contextual and lexical factors both contribute to sentence interpretation without context completely overriding lexical information, and (iii) strong lexical influences remain present for a relatively long period of time.
• Kaan, E. & Swaab, T.Y. (2003). Electrophysiological evidence for serial sentence processing: A comparison between non-preferred and ungrammatical continuations. Cognitive Brain Research, 17, 621-635.
  • Abstract: Event-related potentials (ERPs) were used to address a much debated issue in sentence processing research, namely whether one or multiple interpretations are pursued in case of syntactic ambiguities. For example in the syntactically ambiguous fragment “The man is painting the house and the garage…”, ‘and’ either connects ‘the house’ and ‘the garage’, or conjoins two clauses (e.g., “The man is painting the house and the garage is already finished”). According to serial models, only one syntactic interpretation (the simplest) is pursued first (the first interpretation in the example). If this interpretation is incompatible with subsequently incoming words, the syntactic analysis of the preceding sentence fragment is revised. In contrast, parallel models propose that multiple interpretations of the ambiguity are pursued simultaneously. The two models were tested by comparing ERPs to words that were either ungrammatical, or grammatical but non-preferred continuations of the preceding sentence fragment. In a serial model, these two are not distinguished until after initial revision; in a parallel model, a distinction can be made at an early stage. The results supported a serial model: both with an acceptability judgment and a passive reading task a left lateralized negativity was found for ungrammatical and non-preferred continuations relative to unambiguous grammatical continuations, which indicates that ungrammatical and non-preferred continuations were initially processed in the same way. However, in later time intervals, the ERPs to the ungrammatical continuation showed a posterior positivity (P600), whereas the ERPs to the non-preferred continuation had a more anterior focus, which indicates that they were processed differently.
• Kaan, E. & Swaab, T.Y. (2002). The brain circuitry of syntactic comprehension. Trends in Cognitive Science, 6, 350-356.
  • Abstract: Syntactic comprehension is a fundamental aspect of human language, and has distinct properties from other aspects of language (e.g. semantics). In this article, we aim to identify if there is a specific locus of syntax in the brain by reviewing imaging studies on syntactic processing. We conclude that results from neuroimaging support evidence from neuropsychology that syntactic processing does not recruit one specific area. Instead a network of areas including Broca's area and anterior, middle and superior areas of the temporal lobes is involved. However, none of these areas appears to be syntax specific.
• Swaab, T.Y., Baynes, K., & Knight, R.T. (2002). Separable effects of priming and imageability on word processing: An ERP study. Cognitive Brain Research, 15, 99-103.
  • Abstract: Concrete, highly imageable words (e.g. banana) are easier to understand than abstract words for which it is difficult to generate an image (e.g. justice). This effect of concreteness or imageability has been taken by some as evidence for the existence of separable verbal- and image-based semantic systems. Instead, however, effects of concreteness may result from better associations to relevant contextual representations for concrete than for abstract words within a single semantic system. In this study, target words of high and low imageability were preceded by supportive (related) or non-supportive (unrelated) context words. The influence of contextual support on the imageability effect was measured by recording event-related brain potentials (ERPs) to the high and low imageable target words in both context conditions. The topographic distributions of the ERPs elicited by the high versus low imageable target words were found to be different, and this effect was independent of contextual support. These data are consistent with the idea that distinct verbal- and image-based semantic codes exist for word representations, and that as a result, concrete words that are highly imageable can be understood more easily.
• Swaab, T.Y. (2002). Language and Brain (Chapter 9). In: Gazzaniga, M.S., R., Ivry and G.R. Mangun, Cognitive Neuroscience: The Biology of the Mind. (2nd Edition). W.W. Norton Pub.: New York (Textbook).
• Swaab, T.Y. (1999). The Neurocognition of Language. Trends in Cognitive Sciences, 3, 488-489. (Invited Book Review)
• Swaab, T.Y. (1998). Event-related potentials in cognitive neuropsychology: Methodological considerations and an example from studies of aphasia. Behavior, Research Methods, Instruments and Computers, 30, 157-170.
  • Abstract: Recording event-related potentials (ERPs) from neurological patients introduces some methodological problems that are unique to this type of work. Important issues include, for example, the signal-to-noise ratio in patients relative to control subjects and changes in conductivity that are due to brain lesion. Therefore, in order to be able to reliably interpret possible changes in the ERP effects of brain-damaged patients as reflecting changes in underlying cognitive processes, it is important to clearly identify the factors that might contaminate the results of the experiments and to apply appropriate controls. Possible controls are discussed, and, as an example, some studies illustrating the use of ERPs in aphasic patients are reviewed.
• Swaab, T.Y., Brown, C., & Hagoort, P. (1998). Understanding ambiguous words in sentence contexts: Electrophysiological evidence for delayed contextual selection in Broca’s aphasia. Neuropsychologia, 36, 737-761.
  • Abstract: This study investigates whether spoken sentence comprehension deficits in Broca’s aphasics results from their inability to access the subordinate meaning of ambiguous words (e.g. bank), or alternatively, from a delay in their selection of the contextually appropriate meaning. Twelve Broca’s aphasics and twelve elderly controls were presented with lexical ambiguities in three context conditions, each followed by the same target words. In the concordant condition, the sentence context biased the meaning of the sentence-final ambiguous word that was related to the target. In the discordant condition, the sentence context biased the meaning of the sentence-final ambiguous word that was incompatible with the target. In the unrelated condition, the sentence-final word was unambiguous and unrelated to the target. The task of the subjects was to listen attentively to the stimuli. The activational status of the ambiguous sentence-final words was inferred from the amplitude of the N400 to the targets at two inter-stimulus intervals (ISIs) (100 ms and 1250 ms). At the short ISI, the Broca’s aphasics showed clear evidence of activation of the subordinate meaning. In contrast to elderly controls, however, the Broca’s aphasics were not successful at selecting the appropriate meaning of the ambiguity in the short ISI version of the experiment. But at the long ISI, in accordance with the performance of the elderly controls, the patients were able to successfully complete the contextual selection process. These results indicate that Broca’s aphasics are delayed in the process of contextual selection. It is argued that this finding of delayed selection is compatible with the idea that comprehension deficits in Broca’s aphasia result from a delay in the process of integrating lexical information.
• Swaab, T.Y. (1998). Language and Brain (Chapter 8). In: Gazzaniga, M.S., R., Ivry and G.R. Mangun, Cognitive Neuroscience: The Biology of the Mind. (1st Edition). W.W. Norton Pub.: New York (Textbook).
• Swaab, T.Y., Brown, C., & Hagoort, P. (1997). Spoken sentence comprehension in aphasia: Event-related potential evidence for a lexical integration deficit. Journal of Cognitive Neuroscience, 9, 39-66.
  • Abstract: In this study the N400 component of the event-related potential was used to investigate spoken sentence understanding in Broca's and Wernicke's aphasics. The aim of the study was to determine whether spoken sentence comprehension problems in these patients might result from a deficit in the on-line integration of lexical information. Subjects listened to sentences spoken at a normal rate. In half of these sentences, the meaning of the final word of the sentence matched the semantic specifications of the preceding sentence context. In the other half of the sentences, the sentence-final word was anomalous with respect to the preceding sentence context. The N400 was measured to the sentence-final words in both conditions. The results for the aphasic patients (n = 14) were analyzed according to the severity of their comprehension deficit and compared to a group of 12 neurologically unimpaired age-matched controls, as well as a group of 6 nonaphasic patients with a lesion in the right hemisphere. The nonaphasic brain damaged patients and the aphasic patients with a light comprehension deficit (high comprehenders, n = 7) showed an N400 effect that was comparable to that of the neurologically unimpaired subjects. In the aphasic patients with a moderate to severe comprehension deficit (low comprehenders, n = 7), a reduction and delay of the N400 effect was obtained. In addition, the P300 component was measured in a classical oddball paradigm, in which subjects were asked to count infrequent low tones in a random series of high and low tones. No correlation was found between the occurrence of N400 and P300 effects, indicating that changes in the N400 results were related to the patients' language deficit. Overall, the pattern of results was compatible with the idea that aphasic patients with moderate to severe comprehension problems are impaired in the integration of lexical information into a higher order representation of the preceding sentence context.
• Hagoort P., Brown, C. & Swaab, T.Y. (1996). Lexical-semantic event-related potential effects in patients with left hemisphere lesions and aphasia, and patients with right hemisphere lesions without aphasia. Brain, 119, 627-649.
  • Abstract: Lexical—semantic processing impairments in aphasic patients with left hemisphere lesions and non-aphasic patients with right hemisphere lesions were investigated by recording event-related brain potentials (ERPs) while subjects listened to auditorily presented word pairs. The word pairs consisted of unrelated words, or words that were related in meaning. The related words were either associatively related, e.g. ‘bread-butter’, or were members of the same semantic category without being associatively related, e.g. ‘churchvilla’. The latter relationships are assumed to be more distant than the former ones. The most relevant ERP component in this study is the N400. In elderly control subjects, the N400 amplitude to associatively and semantically related word targets is reduced relative to the N400 elicited by unrelated targets. Compared with this normal N400 effect, the different patient groups showed the following pattern of results: aphasic patients with only minor comprehension deficits (high comprehenders) showed N400 effects of a similar size as the control subjects. In aphasic patients with more severe comprehension deficits (low comprehenders) a clear reduction in the N400 effects was obtained, both for the associative and the semantic word pairs. The patients with right hemisphere lesions showed a normal N400 effect for the associatively related targets, but a trend towards a reduced N400 effect for the semantically related word pairs. A dissociation between the N400 results in the word pair paradigm and P300 results in a classical tone oddball task indicated that the N400 effects were not an aspecific consequence of brain lesion, but were related to the nature of the language comprehension impairment. The conclusions drawn from the ERP results are that comprehension deficits in the aphasic patients are due to an impairment in integrating individual word meanings into an overall meaning representation. Right hemisphere patients are more specifically impaired in the processing of semantically more distant relationships, suggesting the involvement of the right hemisphere in semantically coarse coding.
• Brown, C., Hagoort, P., & Swaab, T.Y. (1996). Neurophysiological evidence for a temporal disorganization in aphasic patients with comprehension deficits. In W. Widdig, I.M. Ohlendorff and J.-P. Malin (Eds.). Current Aphasia Therapy. Freiburg: Hochschulverlag. (p 89-122).
• Swaab, T.Y. (1996). The functional locus of comprehension deficits in aphasia: An electrophysiological approach. Afasiologie, 18 (5), 255 263.