Presentations

Abstract

In general, language comprehension is surprisingly reliable. Listeners very rapidly extract meaning from the unfolding speech signal, on a word-by-word basis, and usually successfully. Research on ‘semantic illusions’ however suggests that under certain conditions, people fail to notice that the linguistic input simply doesn’t make sense. In the current event-related brain potentials (ERP) study we examined whether listeners would spontaneously detect an anomaly in which a human character central to the story at hand (e.g. “a tourist”) was suddenly replaced by an inanimate object (e.g. “a suitcase”). Because this replacement introduced a very powerful coherence break, we expected listeners to immediately notice the anomaly and generate the standard ERP effect associated with incoherent language, the N400 effect. However, instead of the standard N400 effect, anomalous words elicited a differential ERP effect from about 500-700 ms onwards. The absence of an N400 effect indicates that subjects did not immediately notice the anomaly, and that for a few hundred milliseconds the comprehension system has converged on an apparently coherent but factually incorrect interpretation. The presence of the later ERP effect indicates that subjects were processing for comprehension and did ultimately detect the anomaly. Therefore, we take our results to reflect a temporary semantic illusion. Our results also show that even attentive listeners sometimes fail to notice a radical change in the nature of a story character, and therefore demonstrate a case of short-lived ‘change deafness’ in language comprehension.

Abstract

n two ERP-experiments we examined whether discourse context could overrule a local semantic violation. In both experiments, subjects listened to stories in which a person was engaged in conversation with an inanimate object. In experiment 1, story-initial animacy violations reflected in an N400 effect were completely neutralized further down the story. In experiment 2, canonical but story-irrelevant inanimate predicates assigned to the inanimate object elicited an N400 effect, compared to contextually appropriate animate predicates.