About Edible Restaurants: Conflicts between Syntax and Semantics as Revealed by ERPs

The P600 as a continuous index of integration effort

The integration of word meaning into an unfolding utterance representation is a core operation of incremental language comprehension. There is considerable debate, however, as to which component of the ERP signal-the N400 or the P600-directly reflects integrative processes, with far reaching consequences for the temporal organization and architecture of the comprehension system. Multi-stream models maintaining the N400 as integration crucially rely on the presence of a semantically attractive plausible alternative interpretation to account for the absence of an N400 effect in response to certain semantic anomalies, as reported in previous studies. The single-stream Retrieval-Integration account posits the P600 as an index of integration, further predicting that its amplitude varies continuously with integrative effort. Here, we directly test these competing hypotheses using a context manipulation design in which a semantically attractive alternative is either available or not, and target word plausibility is varied across three levels. An initial self-paced reading study revealed graded reading times for plausibility, suggesting differential integration effort. A subsequent ERP study showed no N400 differences across conditions, and that P600 amplitude is graded for plausibility. These findings are inconsistent with the interpretation of the N400 as an index of integration, as no N400 effect emerged even in the absence of a semantically attractive alternative. By contrast, the link between plausibility, reading times, and P600 amplitude supports the view that the P600 is a continuous index of integration effort. More generally, our results support a single-stream architecture and eschew the need for multi-stream accounts.

The effects of grammatical gender on the processing of occupational role names in Slovene: An event-related potential study

The event-related potential method has proven to be a useful tool for studying the effects of gender information in language. Studies have shown that mismatch between the antecedent and the following referent triggers two ERP components, N400 and P600. In the present study, we investigated how grammatical gender affects the mental representation of the grammatical subject. A match-mismatch paradigm was used to investigate how masculine grammatical gender and gender-balanced forms (the explicit mention of masculine and feminine forms as word pairs) as role nouns affect the processing of the referent in Slovenian. The morphological complexity of Slovenian language required the use of anaphoric verbs instead of nouns/pronouns, on which previous research was based. The results showed that following both the gender-balanced and the masculine generic forms, P600 (but not N400) was observed in response to the feminine verb but not to the masculine verb. The P600 amplitude was smaller in the case of the gender-balanced form than in the case of the masculine generic form only. We have concluded that gender-balanced forms are more open to feminine continuations than masculine generic forms. This is the first ERP study in Slovenian to address the effects of processing grammatical gender, thus contributing to existing research on languages with grammatical gender. The great strength of the study is that it is one of the first ERP studies to test the mental inclusivity of gender-balanced forms.

First Event-Related Potentials Evidence of Auditory Morphosyntactic Processing in a Subject-Object-Verb Nominative-Accusative Language (Farsi)

While most studies on neural signals of online language processing have focused on a few-usually western-subject-verb-object (SVO) languages, corresponding knowledge on subject-object-verb (SOV) languages is scarce. Here we studied Farsi, a language with canonical SOV word order. Because we were interested in the consequences of second-language acquisition, we compared monolingual native Farsi speakers and equally proficient bilinguals who had learned Farsi only after entering primary school. We analyzed event-related potentials (ERPs) to correct and morphosyntactically incorrect sentence-final syllables in a sentence correctness judgment task. Incorrect syllables elicited a late posterior positivity at 500-700 ms after the final syllable, resembling the P600 component, as previously observed for syntactic violations at sentence-middle positions in SVO languages. There was no sign of a left anterior negativity (LAN) preceding the P600. Additionally, we provide evidence for a real-time discrimination of phonological categories associated with morphosyntactic manipulations (between 35 and 135 ms), manifesting the instantaneous neural response to unexpected perturbations. The L2 Farsi speakers were indistinguishable from L1 speakers in terms of performance and neural signals of syntactic violations, indicating that exposure to a second language at school entry may results in native-like performance and neural correlates. In nonnative (but not native) speakers verbal working memory capacity correlated with the late posterior positivity and performance accuracy. Hence, this first ERP study of morphosyntactic violations in a spoken SOV nominative-accusative language demonstrates ERP effects in response to morphosyntactic violations and the involvement of executive functions in non-native speakers in computations of subject-verb agreement.

Retrieval (N400) and integration (P600) in expectation-based comprehension

Expectation-based theories of language processing, such as Surprisal theory, are supported by evidence of anticipation effects in both behavioural and neurophysiological measures. Online measures of language processing, however, are known to be influenced by factors such as lexical association that are distinct from—but often confounded with—expectancy. An open question therefore is whether a specific locus of expectancy related effects can be established in neural and behavioral processing correlates. We address this question in an event-related potential experiment and a self-paced reading experiment that independently cross expectancy and lexical association in a context manipulation design. We find that event-related potentials reveal that the N400 is sensitive to both expectancy and lexical association, while the P600 is modulated only by expectancy. Reading times, in turn, reveal effects of both association and expectancy in the first spillover region, followed by effects of expectancy alone in the second spillover region. These findings are consistent with the Retrieval-Integration account of language comprehension, according to which lexical retrieval (N400) is facilitated for words that are both expected and associated, whereas integration difficulty (P600) will be greater for unexpected words alone. Further, an exploratory analysis suggests that the P600 is not merely sensitive to expectancy violations, but rather, that there is a continuous relation. Taken together, these results suggest that the P600, like reading times, may reflect a meaning-centric notion of Surprisal in language comprehension.

An ERP Study on Attraction Effects in Advanced L2 Learners

In English, the rule of agreement is quite simple: verbs must agree with their subject head nouns in terms of number features. Despite this simplicity, agreement processing is always interrupted when the subject phrase of the sentence "The key to the cabinets is on the table," contains two nouns with a mismatch in number features commonly known as attraction effects. This study used event-related potentials (ERPs) to examine whether late advanced second language (L2) learners can acquire native-like sensitivity of attraction effects. The results revealed that L2 learners showed ERP patterns qualitatively similar to native English speakers: ungrammatical verbs following singular attractors elicited a P600 effect relative to their grammatical counterparts, whereas this positivity was replaced by an N400 effect when plural attractors intervened between the subject head nouns and the verbs. Of particular interest, given that, compared to native speakers, the amplitude of the P600 effect elicited by L2 learners was smaller, there was a quantitative difference between native speakers and L2 learners. We proposed that these two ERP components represented the two processing routes of agreement: the P600 effect indexed a full, combinatorial process, which parsed morphosyntactic features between agreement controllers and targets, whereas the N400 effect indexed a shallow, heuristic process, which evaluated lexical associations between agreeing elements. Moreover, similar to native speakers, advanced L2 learners showed an asymmetrical pattern of attraction effects, in that plural attractors were interfered with ungrammaticality at disagreeing verbs, but they did not cause any difficulties in processing grammatical sentences at agreeing verbs. The overall results suggested that compared to native processing, L2 processing of complex agreement with attractor interference was shallower and therefore late advanced L2 learners could not achieve native-like attraction effects.

An ERP index of real-time error correction within a noisy-channel framework of human communication

Recent evidence suggests that language processing is well-adapted to noise in the input (e.g., spelling or speech errors, misreading or mishearing) and that comprehenders readily correct the input via rational inference over possible intended sentences given probable noise corruptions. In the current study, we probed the processing of noisy linguistic input, asking whether well-studied ERP components may serve as useful indices of this inferential process. In particular, we examined sentences where semantic violations could be attributed to noise-for example, in "The storyteller could turn any incident into an amusing antidote", where the implausible word "antidote" is orthographically and phonologically close to the intended "anecdote". We found that the processing of such sentences-where the probability that the message was corrupted by noise exceeds the probability that it was produced intentionally and perceived accurately-was associated with a reduced (less negative) N400 effect and an increased P600 effect, compared to semantic violations which are unlikely to be attributed to noise ("The storyteller could turn any incident into an amusing hearse"). Further, the magnitudes of these ERP effects were correlated with the probability that the comprehender retrieved a plausible alternative. This work thus adds to the growing body of literature that suggests that many aspects of language processing are optimized for dealing with noise in the input, and opens the door to electrophysiologic investigations of the computations that support the processing of imperfect input.

Functional Role of the N400 and P600 in Language-Related ERP Studies with Respect to Semantic Anomalies: An Overview

In this study, the language-related ERP studies relevant to the functional role of the N400 and P600 in semantically anomalous sentences and the underlying reasons which may affect their functions were reviewed. Since their discovery, the N400 and P600 have been the most important language-related ERP components. The N400 has been mostly elicited as a result of processing sentences with lexical and semantic anomalies, but later on, in many studies instead of the expected lexical-semantic N400 effect, semantic anomalies elicited a P600 effect called semantic P600. However, the functional interpretation of these two ERP components has constantly been a matter of debate. Perhaps most notably, it is proposed that it is not just the N400 which is related to semantic anomalies but the P600 can also be reflected as a result of these kinds of anomalies. Reviewing the literature for explaining the functions of the two ERP components, the N400 and the P600, during the processing of semantic anomalies revealed that still there is a need for more research on language processing in order to make the researchers capable of describing the underlying factors influencing them, especially more focused investigations of the functional-anatomical and neurocomputational models may provide a clearer understanding of them. Moreover, any practical theory or model of the N400 and the P600 in language comprehension needs to consider the apparent inconsistencies in the elicitation pattern of the N400 and the P600 in order to successfully capture the full data spectrum.

Distinguishing Syntactic Operations in the Brain: Dependency and Phrase-Structure Parsing

Finding the structure of a sentence-the way its words hold together to convey meaning-is a fundamental step in language comprehension. Several brain regions, including the left inferior frontal gyrus, the left posterior superior temporal gyrus, and the left anterior temporal pole, are supposed to support this operation. The exact role of these areas is nonetheless still debated. In this paper we investigate the hypothesis that different brain regions could be sensitive to different kinds of syntactic computations. We compare the fit of phrase-structure and dependency structure descriptors to activity in brain areas using fMRI. Our results show a division between areas with regard to the type of structure computed, with the left anterior temporal pole and left inferior frontal gyrus favouring dependency structures and left posterior superior temporal gyrus favouring phrase structures.

Expectancy effects in the EEG during joint and spontaneous word-by-word sentence production in German

Our aim in the present study is to measure neural correlates during spontaneous interactive sentence production. We present a novel approach using the word-by-word technique from improvisational theatre, in which two speakers jointly produce one sentence. This paradigm allows the assessment of behavioural aspects, such as turn-times, and electrophysiological responses, such as event-related-potentials (ERPs). Twenty-five participants constructed a cued but spontaneous four-word German sentence together with a confederate, taking turns for each word of the sentence. In 30% of the trials, the confederate uttered an unexpected gender-marked article. To complete the sentence in a meaningful way, the participant had to detect the violation and retrieve and utter a new fitting response. We found significant increases in response times after unexpected words and - despite allowing unscripted language production and naturally varying speech material - successfully detected significant N400 and P600 ERP effects for the unexpected word. The N400 EEG activity further significantly predicted the response time of the subsequent turn. Our results show that combining behavioural and neuroscientific measures of verbal interactions while retaining sufficient experimental control is possible, and that this combination provides promising insights into the mechanisms of spontaneous spoken dialogue.

Studying brain activity during word-by-word interactions using wireless EEG

We introduce here the word-by-word paradigm, a dynamic setting, in which two people take turns in producing a single sentence. This task requires a high degree of coordination between the partners and the simplicity of the task allows us to study with sufficient experimental control behavioral and neural processes that underlie this controlled interaction. For this study, 13 pairs of individuals engaged in a scripted word-by-word interaction, while we recorded the neural activity of both participants simultaneously using wireless EEG. To study expectation building, different semantic contexts were primed for each participant. Semantically unexpected continuations were introduced in 25% of all sentences. In line with the hypothesis, we observed amplitude differences for the P200-N400-P600 ERPs for unexpected compared to expected words. Moreover, we could successfully assess speech and reaction times. Our results show that it is possible to measure ERPs and RTs to semantically unexpected words in a dyadic interactive scenario.

Processing syntax: perspectives on language specificity

Objective: The past few decades of research in language processing provides empirical data on the dimensions of the brain-language relationship. The methodologies used to study language processing have evidenced an immense advancement over the years, tracking real-time processing events with millisecond precision. Event-related potentials is one such method which assists to visualize the neural mechanisms that underlie language processing. Different electrophysiological components mark different components of language depending on their structural and functional aspects. Since research on language processing is expanding its boundaries, the neural mechanisms for processing syntax components have been the focus of recent investigations across the languages of the world. The present review article aims to discuss the findings of studies on syntax processing besides highlighting the functional significance of P600, the electrophysiological marker of syntax processing.Methods: Electronic databases such as Pubmed, Science Direct, Research gate, PLOS, Directory of Open Access Journals were searched for relavant articles. The review process followed PRISMA guidelines for screening, identification, and selection of articles.Results: The results of the review elucidate the need for evaluating the finer details of syntax, including morpho-syntax concerning specific language structures. Studies across the languages of the world exemplify the uniqueness in the structure of different languages that may provide varied perspectives on the universality in syntax processing.Conclusion: The present review contributes a new dimension towards understanding the nature of syntax processing with respect to language specificity.

Going the Extra Mile: Effects of Discourse Context on Two Late Positivities During Language Comprehension

During language comprehension, online neural processing is strongly influenced by the constraints of the prior context. While the N400 ERP response (300-500ms) is known to be sensitive to a word's semantic predictability, less is known about a set of late positive-going ERP responses (600-1000ms) that can be elicited when an incoming word violates strong predictions about upcoming content (late frontal positivity) or about what is possible given the prior context (late posterior positivity/P600). Across three experiments, we systematically manipulated the length of the prior context and the source of lexical constraint to determine their influence on comprehenders' online neural responses to these two types of prediction violations. In Experiment 1, within minimal contexts, both lexical prediction violations and semantically anomalous words produced a larger N400 than expected continuations (James unlocked the door/laptop/gardener), but no late positive effects were observed. Critically, the late posterior positivity/P600 to semantic anomalies appeared when these same sentences were embedded within longer discourse contexts (Experiment 2a), and the late frontal positivity appeared to lexical prediction violations when the preceding context was rich and globally constraining (Experiment 2b). We interpret these findings within a hierarchical generative framework of language comprehension. This framework highlights the role of comprehension goals and broader linguistic context, and how these factors influence both top-down prediction and the decision to update or reanalyze the prior context when these predictions are violated.

The P3b and P600(s): Positive contributions to language comprehension

Since its discovery in the 1960s, the P300 has been contributing both directly and indirectly to language research. Perhaps most notably, it has been suggested that the P600, an ERP component that was first characterized in the context of syntactic processing, could be a variant of the P3b subcomponent of the P300. Here, we review studies on both sides of the debate. We also review the "semantic P600," a positivity with a similar time course and distribution to the P600 seen for syntactic manipulations but that is obtained in response to some types of semantic anomalies. Because most current theories of the P600 try to account for both the syntactic and the semantic variant, linking the syntactic P600 to the P3b might also imply a similar link for the semantic P600. However, we describe emerging research in our lab that casts doubt on the idea that the syntactic P600 and the semantic P600 are the same effect. We argue that grouping ERP responses primarily by domain (language vs. nonlanguage) is likely to be misleading and suggest alternative ways of determining whether ERP effects reflect similar or different processing mechanisms.

Dissociating predictability, plausibility and possibility of sentence continuations in reading: evidence from late-positivity ERPs

Late positive event-related potential (ERP) components occurring after the N400, traditionally linked to reanalysis due to syntactic incongruence, are increasingly considered to also reflect reanalysis and repair due to semantic difficulty. Semantic problems can have different origins, such as a mismatch of specific predictions based on the context, low plausibility, or even semantic impossibility of a word in the given context. DeLong, Quante & Kutas (2014) provided the first direct evidence for topographically different late positivities for prediction mismatch (left frontal late positivity for plausible but unexpected words) and plausibility violation (posterior-parietal late positivity for implausible, incongruent words). The aim of the current study is twofold: (1) to replicate this dissociation of ERP effects for plausibility violations and prediction mismatch in a different language, and (2) to test an additional contrast within implausible words, comparing impossible and possible sentence continuations. Our results replicate DeLong, Quante & Kutas (2014) with different materials in a different language, showing graded effects for predictability and plausibility at the level of the N400, a dissociation of plausible and implausible, anomalous continuations in posterior late positivities and an effect of prediction mismatch on late positivities at left-frontal sites. In addition, we found some evidence for a dissociation, at these left-frontal sites, between implausible words that were fully incompatible with the preceding discourse and those for which an interpretation is possible.

The N400 Effect during Speaker-Switch-Towards a Conversational Approach of Measuring Neural Correlates of Language

Language occurs naturally in conversations. However, the study of the neural underpinnings of language has mainly taken place in single individuals using controlled language material. The interactive elements of a conversation (e.g., turn-taking) are often not part of neurolinguistic setups. The prime reason is the difficulty to combine open unrestricted conversations with the requirements of neuroimaging. It is necessary to find a trade-off between the naturalness of a conversation and the restrictions imposed by neuroscientific methods to allow for ecologically more valid studies. Here, we make an attempt to study the effects of a conversational element, namely turn-taking, on linguistic neural correlates, specifically the N400 effect. We focus on the physiological aspect of turn-taking, the speaker-switch, and its effect on the detectability of the N400 effect. The N400 event-related potential reflects expectation violations in a semantic context; the N400 effect describes the difference of the N400 amplitude between semantically expected and unexpected items. Sentences with semantically congruent and incongruent final words were presented in two turn-taking modes: (1) reading aloud first part of the sentence and listening to speaker-switch for the final word, and (2) listening to first part of the sentence and speaker-switch for the final word. A significant N400 effect was found for both turn-taking modes, which was not influenced by the mode itself. However, the mode significantly affected the P200, which was increased for the reading aloud mode compared to the listening mode. Our results show that an N400 effect can be detected during a speaker-switch. Speech articulation (reading aloud) before the analyzed sentence fragment did also not impede the N400 effect detection for the final word. The speaker-switch, however, seems to influence earlier components of the electroencephalogram, related to processing of salient stimuli. We conclude that the N400 can effectively be used to study neural correlates of language in conversational approaches including speaker-switches.

Effects of Type of Agreement Violation and Utterance Position on the Auditory Processing of Subject-Verb Agreement: An ERP Study

Previous ERP studies have often reported two ERP components-LAN and P600-in response to subject-verb (S-V) agreement violations (e.g., the boys (*) runs). However, the latency, amplitude and scalp distribution of these components have been shown to vary depending on various experiment-related factors. One factor that has not received attention is the extent to which the relative perceptual salience related to either the utterance position (verbal inflection in utterance-medial vs. utterance-final contexts) or the type of agreement violation (errors of omission vs. errors of commission) may influence the auditory processing of S-V agreement. The lack of reports on these effects in ERP studies may be due to the fact that most studies have used the visual modality, which does not reveal acoustic information. To address this gap, we used ERPs to measure the brain activity of Australian English-speaking adults while they listened to sentences in which the S-V agreement differed by type of agreement violation and utterance position. We observed early negative and positive clusters (AN/P600 effects) for the overall grammaticality effect. Further analysis revealed that the mean amplitude and distribution of the P600 effect was only significant in contexts where the S-V agreement violation occurred utterance-finally, regardless of type of agreement violation. The mean amplitude and distribution of the negativity did not differ significantly across types of agreement violation and utterance position. These findings suggest that the increased perceptual salience of the violation in utterance final position (due to phrase-final lengthening) influenced how S-V agreement violations were processed during sentence comprehension. Implications for the functional interpretation of language-related ERPs and experimental design are discussed.

When language comprehension goes wrong for the right reasons: Good-enough, underspecified, or shallow language processing

This paper contains an overview of language processing that can be described as "good enough", "underspecified", or "shallow". The central idea is that a nontrivial proportion of misunderstanding, misinterpretation, and miscommunication can be attributed not to random error, but instead to processing preferences of the human language processing system. In other words, the very architecture of the language processor favours certain types of processing errors because in a majority of instances, this "fast and frugal", less effortful processing is good enough to support communication. By way of historical background, connections are made between this relatively recent facet of psycholinguistic study, other recent language processing models, and related concepts in other areas of cognitive science. Finally, the nine papers included in this special issue are introduced as representative of novel explorations of good-enough, or underspecified, language processing.

Getting a cue before getting a clue: Event-related potentials to inference in visual narrative comprehension

Inference has long been emphasized in the comprehension of verbal and visual narratives. Here, we measured event-related brain potentials to visual sequences designed to elicit inferential processing. In Impoverished sequences, an expressionless "onlooker" watches an undepicted event (e.g., person throws a ball for a dog, then watches the dog chase it) just prior to a surprising finale (e.g., someone else returns the ball), which should lead to an inference (i.e., the different person retrieved the ball). Implied sequences alter this narrative structure by adding visual cues to the critical panel such as a surprised facial expression to the onlooker implying they saw an unexpected, albeit undepicted, event. In contrast, Expected sequences show a predictable, but then confounded, event (i.e., dog retrieves ball, then different person returns it), and Explicit sequences depict the unexpected event (i.e., different person retrieves then returns ball). At the critical penultimate panel, sequences representing depicted events (Explicit, Expected) elicited a larger posterior positivity (P600) than the relatively passive events of an onlooker (Impoverished, Implied), though Implied sequences were slightly more positive than Impoverished sequences. At the subsequent and final panel, a posterior positivity (P600) was greater to images in Impoverished sequences than those in Explicit and Implied sequences, which did not differ. In addition, both sequence types requiring inference (Implied, Impoverished) elicited a larger frontal negativity than those explicitly depicting events (Expected, Explicit). These results show that neural processing differs for visual narratives omitting events versus those depicting events, and that the presence of subtle visual cues can modulate such effects presumably by altering narrative structure.

Quantifiers are incrementally interpreted in context, more than less

Language interpretation is often assumed to be incremental. However, our studies of quantifier expressions in isolated sentences found N400 event-related brain potential (ERP) evidence for partial but not full immediate quantifier interpretation (Urbach & Kutas, 2010). Here we tested similar quantifier expressions in pragmatically supporting discourse contexts (Alex was an unusual toddler. Most/Few kids prefer sweets/vegetables…) while participants made plausibility judgments (Experiment 1) or read for comprehension (Experiment 2). Control Experiments 3A (plausibility) and 3B (comprehension) removed the discourse contexts. Quantifiers always modulated typical and/or atypical word N400 amplitudes. However, only the real-time N400 effects only in Experiment 2 mirrored offline quantifier and typicality crossover interaction effects for plausibility ratings and cloze probabilities. We conclude that quantifier expressions can be interpreted fully and immediately, though pragmatic and task variables appear to impact the speed and/or depth of quantifier interpretation.

The P600-as-P3 hypothesis revisited: single-trial analyses reveal that the late EEG positivity following linguistically deviant material is reaction time aligned

The P600, a late positive ERP component following linguistically deviant stimuli, is commonly seen as indexing structural, high-level processes, e.g. of linguistic (re)analysis. It has also been identified with the P3 (P600-as-P3 hypothesis), which is thought to reflect a systemic neuromodulator release facilitating behavioural shifts and is usually response time aligned. We investigated single-trial alignment of the P600 to response, a critical prediction of the P600-as-P3 hypothesis. Participants heard sentences containing morphosyntactic and semantic violations and responded via a button press. The elicited P600 was perfectly response aligned, while an N400 following semantic deviations was stimulus aligned. This is, to our knowledge, the first single-trial analysis of language processing data using within-sentence behavioural responses as temporal covariates. Results support the P600-as-P3 perspective and thus constitute a step towards a neurophysiological grounding of language-related ERPs.

Context-dependent Semantic Processing in the Human Brain: Evidence from Idiom Comprehension

Language comprehension involves activating word meanings and integrating them with the sentence context. This study examined whether these routines are carried out even when they are theoretically unnecessary, namely, in the case of opaque idiomatic expressions, for which the literal word meanings are unrelated to the overall meaning of the expression. Predictable words in sentences were replaced by a semantically related or unrelated word. In literal sentences, this yielded previously established behavioral and electrophysiological signatures of semantic processing: semantic facilitation in lexical decision, a reduced N400 for semantically related relative to unrelated words, and a power increase in the gamma frequency band that was disrupted by semantic violations. However, the same manipulations in idioms yielded none of these effects. Instead, semantic violations elicited a late positivity in idioms. Moreover, gamma band power was lower in correct idioms than in correct literal sentences. It is argued that the brain's semantic expectancy and literal word meaning integration operations can, to some extent, be “switched off” when the context renders them unnecessary. Furthermore, the results lend support to models of idiom comprehension that involve unitary idiom representations.

CNTNAP2 and language processing in healthy individuals as measured with ERPs

The genetic FOXP2-CNTNAP2 pathway has been shown to be involved in the language capacity. We investigated whether a common variant of CNTNAP2 (rs7794745) is relevant for syntactic and semantic processing in the general population by using a visual sentence processing paradigm while recording ERPs in 49 healthy adults. While both AA homozygotes and T-carriers showed a standard N400 effect to semantic anomalies, the response to subject-verb agreement violations differed across genotype groups. T-carriers displayed an anterior negativity preceding the P600 effect, whereas for the AA group only a P600 effect was observed. These results provide another piece of evidence that the neuronal architecture of the human faculty of language is shaped differently by effects that are genetically determined.

Individual variation in the late positive complex to semantic anomalies

It is well-known that, within ERP paradigms of sentence processing, semantically anomalous words elicit N400 effects. Less clear, however, is what happens after the N400. In some cases N400 effects are followed by Late Positive Complexes (LPC), whereas in other cases such effects are lacking. We investigated several factors which could affect the LPC, such as contextual constraint, inter-individual variation, and working memory. Seventy-two participants read sentences containing a semantic manipulation (Whipped cream tastes sweet/anxious and creamy). Neither contextual constraint nor working memory correlated with the LPC. Inter-individual variation played a substantial role in the elicitation of the LPC with about half of the participants showing a negative response and the other half showing an LPC. This individual variation correlated with a syntactic ERP as well as an alternative semantic manipulation. In conclusion, our results show that inter-individual variation plays a large role in the elicitation of the LPC and this may account for the diversity in LPC findings in language research.