Computing and recomputing discourse models: An ERP study

Abstract

ABSTRACT. While syntactic reanalysis has been extensively investigated in psycholinguistics, comparatively little is known about reanalysis in the semantic domain. We used event-related brain potentials (ERPs) to keep track of semantic processes involved in understanding short narratives such as 'The girl was writing a letter when her friend spilled coffee on the paper'.We hypothesize that these sentences are interpreted in two steps: (1) when the progressive clause is processed, a discourse model is computed in which the goal state (a complete letter) is predicted to occur; (2) when the subordinate clause is processed, the initial representation is recomputed to the effect that, in the final discourse structure, the goal state is not satisfied.Critical sentences evoked larger sustained anterior negativities (SAN) compared to controls, starting around 400 ms following the onset of the sentence-final word, and lasting for about 400 ms. The amplitude of the SAN was correlated with the frequency with which participants, in an off-line probe-selection task, responded that the goal state was not attained. Our results raise the possibility that the brain supports some form of non-monotonic recomputation to integrate information which invalidates previously held assumptions.

Reasoning with Exceptions: An Event-related Brain Potentials Study

“…This explanation is supported by Baggio et al (2008), who also found a sustained negativity when a default inference had to be overridden and revised, albeit that the scalp distribution of the observed effect in our study was more central than in their study. Alternatively, the sustained negativity may reflect an attempt to link the exception with information retrieved from long-term memory, or extra working memory demands to hold information about the exception in mind in order to withdraw the conclusion (Markovits & Potvin, 2001;Vadeboncoeur & Markovits, 1999;Rösler, Heil, & Glowalla, 1993).…”

“…They suggested that the sustained negativity may reflect inhibitory processes to suppress a representation that is in conflict with world knowledge. Finally, Baggio, van Lambalgen, and Hagoort (2008) found a sustained anterior negativity in defeasible inferences. Participants read sentences such as "The girl was writing a letter when her friend spilled coffee on the paper/tablecloth."…”

“…There are two possible referents for the ambiguous noun in Van Berkum, ; in object-relative sentences, the head noun phrase has both a subject and object role; in the study of Münte et al (1998), there may have been a default representation of events in chronological order as well as the actual, nonchronological order of events; and finally, in Baggio et al (2008), there is a default representation that "writing a letter" has a completed letter as goal state, whereas the "spilling coffee event" requires one to revise this implication. In sum, the sustained negativity may reflect recomputation or additional processing in order to come up with a meaningful representation, or extra working memory load due to multiple representations.…”

The Processing Consequences of Compositionality

“…search and selection of the appropriate meaning but not to recomputation, as in the second account. These operations might give rise to different neurophysiological responses (Baggio et al 2008a), so in principle the two accounts can be tested experimentally.…”

Intuitions and Competence in Formal Semantics

“…Further reasons to doubt that intuitions are really independent of cognitive tasks comes from experiments that show a remarkable shift in neural activity if native speakers are asked to reflect on their intuitions. Cf., Baggio et al (2008) for a case study involving the progressive paradox. It should be stressed that the point here is not that scholars/scientists should not use their intuitions about what is relevant and what is not: there is always construction, and this happens in every discipline, and intuitions (in the sense of 'gut feelings', 'hunches', etc) are an integral part of that.…”