Processing linguistic complexity and grammaticality in the left frontal cortex

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Daily Eastern News: April 30, 1990

https://thekeep.eiu.edu/den_1990_apr/1020/thumbnail.jp

"And yet it moves" or why grammar overrides frequency: A reply to Kempen and Harbusch

We show that Kempen and Harbusch's (Cognition (2003) this issue) arguments against our claims cannot be upheld. On the one hand, their alternative account of our data that is based on the availability of constructions with object-experiencer verbs is not compatible with the literature on the processing of these types of sentences in German. Moreover, their allegation that we failed to conduct an accurate corpus count is simply a misreading of our paper. Insofar, the commentary in no way casts doubt on our claim that grammatical regularities override frequency during online comprehension

Grammar overrides frequency: Evidence from the online processing of flexible word order

We show that online processing difficulties induced by word order variations in German cannot be attributed to the relative infrequency of the constructions in question, but rather appear to reflect the application of grammatical principles during parsing. Event-related brain potentials revealed that dative-marked objects in the initial position of an embedded sentence do not elicit a neurophysiologically distinct response from subjects, whereas accusative-marked objects do. These differences are predictable on the basis of grammatical distinctions (i.e. underlying linguistic properties), but not on the basis of frequency information (i.e. a superficial linguistic property). We therefore conclude that the former, but not the latter, guides syntactic integration during online parsing

Contextual information modulates initial processes of syntactic integration: the role of inter- versus intrasentential predictions

The authors demonstrate that intersentential context may influence syntactic integration processes during online sentence comprehension, although this influence appears to be restricted to cases in which a contextual requirement must be fulfilled. By applying event-related brain potentials to the processing of clause-medial word order variations in German, the authors show that the local processing difficulty (a negativity from 300 to 450 ms) observed for object-initial sentences in a neutral context is also obtained in a (behaviorally) facilitating context in which the object is contextually given. By contrast, the processing pattern for a focused (questioned) initial object does not differ from that for a focused subject: both elicit a parietal positivity (280-480 ms) post-onset of the focused phrase. The authors interpret this early positivity as a general marker of focus integration, a process that appears to briefly supersede sentence-internal requirements

Beyond syntax: Language-related positivities reflect the revision of hierarchies

On the basis of an experiment using event-related brain potentials (EPRs), we argue that a characterisation of language-related positivities as necessarily syntax-related is too restrictive. Our data show that, in verb-final German clauses, the processing of a verb which disconfirms the expectations with regard to the hierarchical thematic structure of a sentence (who is doing what to whom) gives rise to an early (200-600 ms) parietal positivity. Thus, positive ERP components elicited during language processing appear to be related to operations (most often revisions) applying to hierarchically structured linguistic information in general, rather than to syntactic structure in particular

Towards a Computational Model of Actor-Based Language Comprehension

Neurophysiological data from a range of typologically diverse languages provide evidence for a cross-linguistically valid, actor-based strategy of understanding sentence-level meaning. This strategy seeks to identify the participant primarily responsible for the state of affairs (the actor) as quickly and unambiguously as possible, thus resulting in competition for the actor role when there are multiple candidates. Due to its applicability across languages with vastly different characteristics, we have proposed that the actor strategy may derive from more basic cognitive or neurobiological organizational principles, though it is also shaped by distributional properties of the linguistic input (e.g. the morphosyntactic coding strategies for actors in a given language). Here, we describe an initial computational model of the actor strategy and how it interacts with language-specific properties. Specifically, we contrast two distance metrics derived from the output of the computational model (one weighted and one unweighted) as potential measures of the degree of competition for actorhood by testing how well they predict modulations of electrophysiological activity engendered by language processing. To this end, we present an EEG study on word order processing in German and use linear mixed-effects models to assess the effect of the various distance metrics. Our results show that a weighted metric, which takes into account the weighting of an actor-identifying feature in the language under consideration outperforms an unweighted distance measure. We conclude that actor competition effects cannot be reduced to feature overlap between multiple sentence participants and thereby to the notion of similarity-based interference, which is prominent in current memory-based models of language processing. Finally, we argue that, in addition to illuminating the underlying neurocognitive mechanisms of actor competition, the present model can form the basis for a more comprehensive, neurobiologically plausible computational model of constructing sentence-level meaning

The emergence of the unmarked: A new perspective on the language-specific function of Broca's Area

A number of neuroimaging studies have implicated an involvement of Broca's area, particularly of the pars opercularis of the left inferior frontal gyrus (IFG), in the processing of complex (permuted) sentences. However, functional interpretations of this region's role range from very general (e.g., in terms of working memory) to highly specific (e.g., as supporting particular types of syntactic operations). A dissociation of these competing accounts is often impossible because in most cases, the language internal complexity of permuted sentence structures is accompanied invariably by increasing costs of a more general cognitive nature (e.g., working memory, task difficulty, and acceptability). We used functional magnetic resonance imaging to explore the precise nature of the pars opercularis activation in the processing of permuted sentences by examining the permutation of pronouns in German. Although clearly involving a permutation operation, sentences with an initial object pronoun behave like simple, subject-initial sentences (e.g., in terms of acceptability) because of a rule stating that pronouns should generally precede non-pro-nominal arguments. The results of the experiment show that in contrast to non-pro-nominal permutations, sentences with a permuted pronoun do not engender enhanced pars opercularis activation. Our findings therefore speak against both language-related working memory and transformation-based accounts of this region's role in sentence comprehension. Rather, we argue that the pars opercularis of the left IFG supports the language-specific linearization of hierarchical linguistic dependencies

Electrophysiology Reveals the Neural Dynamics of Naturalistic Auditory Language Processing: Event-Related Potentials Reflect Continuous Model Update

The recent trend away from ANOVA-based analyses places experimental investigations into the neurobiology of cognition in more naturalistic and ecologically valid designs within reach. Using mixed-effects models for epoch-based regression, we demonstrate the feasibility of examining event-related potentials (ERPs), and in particular the N400, to study the neural dynamics of human auditory language processing in a naturalistic setting. Despite the large variability between trials during naturalistic stimulation, we replicated previous findings from the literature: the effects of frequency, animacy, word order and find previously unexplored interaction effects. This suggests a new perspective on ERPs, namely as a continuous modulation reflecting continuous stimulation instead of a series of discrete and essentially sequential processes locked to discrete events. Significance Statement Laboratory experiments on language often lack ecologicalal validity. In addition to the intrusive laboratory equipment, the language used is often highly constrained in an attempt to control possible confounds. More recent research with naturalistic stimuli has been largely confined to fMRI, where the low temporal resolution helps to smooth over the uneven finer structure of natural language use. Here, we demonstrate the feasibility of using naturalistic stimuli with temporally sensitive methods such as EEG and MEG using modern computational approaches and show how this provides new insights into the nature of ERP components and the temporal dynamics of language as a sensory and cognitive process. The full complexity of naturalistic language use cannot be captured by carefully controlled designs alone