Publications

Abstract

In a recent article in Cognition, Delaney-Busch et al. (2019) claim evidence for ‘rational’, Bayesian adaptation of semantic predictions, using ERP data from Lau, Holcomb, and Kuperberg (2013). Participants read associatively related and unrelated prime-target word pairs in a first block with only 10% related trials and a second block with 50%. Related words elicited smaller N400s than unrelated words, and this difference was strongest in the second block, suggesting greater engagement in predictive processing. Using a rational adaptor model, Delaney-Busch et al. argue that the stronger N400 reduction for related words in the second block developed as a function of the number of related trials, and concluded therefore that participants predicted related words more strongly when their predictions were fulfilled more often. In this critique, I discuss two critical flaws in their analyses, namely the confounding of prediction effects with those of lexical frequency and the neglect of data from the first block. Re-analyses suggest a different picture: related words by themselves did not yield support for their conclusion, and the effect of relatedness gradually strengthened in othe two blocks in a similar way. Therefore, the N400 did not yield evidence that participants rationally adapted their semantic predictions. Within the framework proposed by Delaney-Busch et al., presumed semantic predictions may even be thought of as ‘irrational’. While these results yielded no evidence for rational or probabilistic prediction, they do suggest that participants became increasingly better at predicting target words from prime words.

Abstract

In two ERP experiments, we investigated whether readers prioritize animacy over real-world event-knowledge during sentence comprehension. We used the paradigm of Paczynski and Kuperberg (2012), who argued that animacy is prioritized based on the observations that the ‘related anomaly effect’ (reduced N400s for context-related anomalous words compared to unrelated words) does not occur for animacy violations, and that animacy violations but not relatedness violations elicit P600 effects. Participants read passive sentences with plausible agents (e.g., The prescription for the mental disorder was written by the psychiatrist) or implausible agents that varied in animacy and semantic relatedness (schizophrenic/guard/pill/fence). In Experiment 1 (with a plausibility judgment task), plausible sentences elicited smaller N400s relative to all types of implausible sentences. Crucially, animate words elicited smaller N400s than inanimate words, and related words elicited smaller N400s than unrelated words, but Bayesian analysis revealed substantial evidence against an interaction between animacy and relatedness. Moreover, at the P600 time-window, we observed more positive ERPs for animate than inanimate words and for related than unrelated words at anterior regions. In Experiment 2 (without judgment task), we observed an N400 effect with animacy violations, but no other effects. Taken together, the results of our experiments fail to support a prioritized role of animacy information over real-world event-knowledge, but they support an interactive, constraint-based view on incremental semantic processing.

Abstract

In an event-related fMRI study, we examined the cortical networks involved in establishing reference during language comprehension. We compared BOLD responses to sentences containing referentially ambiguous pronouns (e.g., “Ronald told Frank that he…”), referentially failing pronouns (e.g., “Rose told Emily that he…”) or coherent pronouns. Referential ambiguity selectively recruited medial prefrontal regions, suggesting that readers engaged in problem-solving to select a unique referent from the discourse model. Referential failure elicited activation increases in brain regions associated with morpho-syntactic processing, and, for those readers who took failing pronouns to refer to unmentioned entities, additional regions associated with elaborative inferencing were observed. The networks activated by these two referential problems did not overlap with the network activated by a standard semantic anomaly. Instead, we observed a double dissociation, in that the systems activated by semantic anomaly are deactivated by referential ambiguity, and vice versa. This inverse coupling may reflect the dynamic recruitment of semantic and episodic processing to resolve semantically or referentially problematic situations. More generally, our findings suggest that neurocognitive accounts of language comprehension need to address not just how we parse a sentence and combine individual word meanings, but also how we determine who's who and what's what during language comprehension.

Abstract

In this event-related brain potentials (ERPs) study, we explored the possibility to selectively track referential ambiguity during spoken discourse comprehension. Earlier ERP research has shown that referentially ambiguous nouns (e.g., “the girl” in a two-girl context) elicit a frontal, sustained negative shift relative to unambiguous control words. In the current study, we examined whether this ERP effect reflects “deep” situation model ambiguity or “superficial” textbase ambiguity. We contrasted these different interpretations by investigating whether a discourse-level semantic manipulation that prevents referential ambiguity also averts the elicitation of a referentially induced ERP effect. We compared ERPs elicited by nouns that were referentially nonambiguous but were associated with two discourse entities (e.g., “the girl” with two girls introduced in the context, but one of which has died or left the scene), with referentially ambiguous and nonambiguous control words. Although temporally referentially ambiguous nouns elicited a frontal negative shift compared to control words, the “double bound” but referentially nonambiguous nouns did not. These results suggest that it is possible to selectively track referential ambiguity with ERPs at the level that is most relevant to discourse comprehension, the situation model.

Abstract

Background Recently several studies have shown that people use contextual information to make predictions about the rest of the sentence or story as the text unfolds. Using event related potentials (ERPs) we tested whether these on-line predictions are based on a message-based representation of the discourse or on simple automatic activation by individual words. Subjects heard short stories that were highly constraining for one specific noun, or stories that were not specifically predictive but contained the same prime words as the predictive stories. To test whether listeners make specific predictions critical nouns were preceded by an adjective that was inflected according to, or in contrast with, the gender of the expected noun. Results When the message of the preceding discourse was predictive, adjectives with an unexpected gender-inflection evoked a negative deflection over right-frontal electrodes between 300 and 600 ms. This effect was not present in the prime control context, indicating that the prediction mismatch does not hinge on word-based priming but is based on the actual message of the discourse. Conclusions When listening to a constraining discourse people rapidly make very specific predictions about the remainder of the story, as the story unfolds. These predictions are not simply based on word-based automatic activation, but take into account the actual message of the discourse.

Abstract

The electrophysiology of language comprehension has long been dominated by research on syntactic and semantic integration. However, to understand expressions like "he did it" or "the little girl", combining word meanings in accordance with semantic and syntactic constraints is not enough--readers and listeners also need to work out what or who is being referred to. We review our event-related brain potential research on the processes involved in establishing reference, and present a new experiment in which we examine when and how the implicit causality associated with specific interpersonal verbs affects the interpretation of a referentially ambiguous pronoun. The evidence suggests that upon encountering a singular noun or pronoun, readers and listeners immediately inspect their situation model for a suitable discourse entity, such that they can discriminate between having too many, too few, or exactly the right number of referents within at most half a second. Furthermore, our implicit causality findings indicate that a fragment like "David praised Linda because..." can immediately foreground a particular referent, to the extent that a subsequent "he" is at least initially construed as a syntactic error. In all, our brain potential findings suggest that referential processing is highly incremental, and not necessarily contingent upon the syntax. In addition, they demonstrate that we can use ERPs to relatively selectively keep track of how readers and listeners establish reference.

Abstract

In linguistic theories of how sentences encode meaning, a distinction is often made between the context-free rule-based combination of lexical–semantic features of the words within a sentence (‘‘semantics’’), and the contributions made by wider context (‘‘pragmatics’’). In psycholinguistics, this distinction has led to the view that listeners initially compute a local, context-independent meaning of a phrase or sentence before relating it to the wider context. An important aspect of such a two-step perspective on interpretation is that local semantics cannot initially be overruled by global contextual factors. In two spoken-language event-related potential experiments, we tested the viability of this claim by examining whether discourse context can overrule the impact of the core lexical–semantic feature animacy, considered to be an innate organizing principle of cognition. Two-step models of interpretation predict that verb–object animacy violations, as in ‘‘The girl comforted the clock,’’ will always perturb the unfolding interpretation process, regardless of wider context. When presented in isolation, such anomalies indeed elicit a clear N400 effect, a sign of interpretive problems. However, when the anomalies were embedded in a supportive context (e.g., a girl talking to a clock about his depression), this N400 effect disappeared completely. Moreover, given a suitable discourse context (e.g., a story about an amorous peanut), animacyviolating predicates (‘‘the peanut was in love’’) were actually processed more easily than canonical predicates (‘‘the peanut was salted’’). Our findings reveal that discourse context can immediately overrule local lexical–semantic violations, and therefore suggest that language comprehension does not involve an initially context-free semantic analysis.

Abstract

Although we usually have no trouble finding the right antecedent for a pronoun, the co-reference relations between pronouns and antecedents in everyday language are often ‘formally’ ambiguous. But a pronoun is only really ambiguous if a reader or listener indeed perceives it to be ambiguous. Whether this is the case may depend on at least two factors: the language processing skills of an individual reader, and the contextual bias towards one particular referential interpretation. In the current study, we used event related brain potentials (ERPs) to explore how both these factors affect the resolution of referentially ambiguous pronouns. We compared ERPs elicited by formally ambiguous and non-ambiguous pronouns that were embedded in simple sentences (e.g., “Jennifer Lopez told Madonna that she had too much money.”). Individual differences in language processing skills were assessed with the Reading Span task, while the contextual bias of each sentence (up to the critical pronoun) had been assessed in a referential cloze pretest. In line with earlier research, ambiguous pronouns elicited a sustained, frontal negative shift relative to non-ambiguous pronouns at the group-level. The size of this effect was correlated with Reading Span score, as well as with contextual bias. These results suggest that whether a reader perceives a formally ambiguous pronoun to be ambiguous is subtly co-determined by both individual language processing skills and contextual bias.