On sense and reference: Examining the functional neuroanatomy of referential 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 problemsolving 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.

The interplay between semantic and referential aspects of anaphoric noun phrase resolution: Evidence from ERPs

“…Because our language comprehension system has only limited processing capacity, this focus on reestablishing semantic coherence diverted readers' attention from the 'smaller concern' imposed by referential ambiguity. 4 As such, the current results provide convergent evidence that engaging in referential ambiguity resolution (as reflected by the referentially induced ERP effect) involves elaborate anaphoric inferencing (Nieuwland et al, 2007b;Nieuwland & Van Berkum, 2006; see also Greene et al, 1992).…”

“…One way this might go is that referential ambiguity adds to the unexpectedness of a semantically incoherent anaphor (equivalent to the 'syntactic boost'; Hagoort, 2003), causing the combined violations to elicit a larger N400 effect than single semantic anomalies. Alternatively, referential ambiguity resolution involves making an anaphoric inference to decide between the referential candidates (Nieuwland et al, 2007b), and this process may be more difficult when the antecedents are both implausible than when they are both plausible, as the ambiguity now has to be resolved with even fewer cues to which antecedent fits best. This could cause the combined violations to elicit a larger referential ambiguity ERP effect than referential ambiguity alone.…”

“…Moreover, results from a functional magnetic resonance imaging (fMRI) study (Nieuwland, Petersson, & Van Berkum, 2007b) seem to extend this notion to a neural systems level. In this study, referentially ambiguous pronouns selectively recruited medial prefrontal regions, suggesting that readers engaged in controlled inferencing (problem-solving) to evaluate the two antecedents in the discourse model and to make an anaphoric inference (Greene, McKoon, & Ratcliff, 1992).…”

Event-related brain potentials index cue-based retrieval interference during sentence comprehension

“…Referential ambiguity, the difficulty in interpretation which arises whenever language users are unable to converge on a unique referent (e.g., noun phrase anaphor or pronoun in the extent literature) from multiple candidates in the discourse, is known to evoke a sustained anterior negativity (the Nref; Van Berkum et al, 1999). Possibly related sustained negativities have been reported when participants interpret a pronoun with an unexpected gender as referring to an unmentioned person (see Osterhout and Mobley, 1995;King and Kutas, 1997; see also Kutas et al, 2000;Nieuwland et al, 2007b). Importantly, it stands to argue that, while an elided constituent is not a proform or a trace (Johnson, 2001), grammatically incorrect determiners during ellipsis may similarly constitute a referential (rather than only a strictly morphosyntactic) problem, when it is insufficient to retrieve a unique antecedent.…”

The Anterior Midline Field: Coercion or decision making?

“…A survey of the literature does, however, reveal several studies where ventromedial effects of semantic processing have been identified. For example, the ventromedial prefrontal cortex (VMF) has been reported to show increased activation for referentially ambiguous expressions in fMRI (Nieuwland, Petersson, & Van Berkum, 2007). In ERPs, similar manipulations have elicited increased anterior negativities, qualitatively different from the N400 response associated with semantic anomalies (Van Berkum, Brown, Hagoort, & Zwitserlood, 2003;Van Berkum, Koornneef, Otten, & Nieuwland, 2007).…”