title: Disentangling stimulus plausibility and contextual congruency: Electro-physiological evidence for differential cognitive dynamics.
abstract: Expectancy mechanisms are routinely used by the cognitive system in stimulus processing and in anticipation of appropriate responses. Electrophysiology research has documented negative shifts of brain activity when expectancies are violated within a local stimulus context (e.g., reading an implausible word in a sentence) or more globally between consecutive stimuli (e.g., a narrative of images with an incongruent end). In this EEG study, we examine the interaction between expectancies operating at the level of stimulus plausibility and at more global level of contextual congruency to provide evidence for, or against, a disassociation of the underlying processing mechanisms. We asked participants to verify the congruency of pairs of cross-modal stimuli (a sentence and a scene), which varied in plausibility. ANOVAs on ERP amplitudes in selected windows of interest show that congruency violation has longer-lasting (from 100 to 500ms) and more widespread effects than plausibility violation (from 200 to 400ms). We also observed critical interactions between these factors, whereby incongruent and implausible pairs elicited stronger negative shifts than their congruent counterpart, both early on (100-200ms) and between 400-500ms. Our results suggest that the integration mechanisms are sensitive to both global and local effects of expectancy in a modality independent manner. Overall, we provide novel insights into the interdependence of expectancy during meaning integration of cross-modal stimuli in a verification task.
authors.affiliation: School of Philosophy, Psychology and Language Sciences, University of Edinburgh, 3 Charles Street, Edinburgh EH8 9AD, UK; Faculdade de Psicologia, Universidade de Lisboa, Portugal. Electronic address: moreno.cocoi@gmail.com.
authors.forename: Moreno I
authors.initials: MI
authors.lastname: Coco
authors.affiliation: Cognitive Neuroscience Research Group, Centre for Biomedical Research (CBMR), University of Algarve, Portugal; Faculdade de Psicologia, Universidade de Lisboa, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Araujo
authors.affiliation: Cognitive Neuroscience Research Group, Centre for Biomedical Research (CBMR), University of Algarve, Portugal; Max Planck Institute for Psycholinguistics, Nijmegen, the Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, the Netherlands.
authors.forename: Karl Magnus
authors.initials: KM
authors.lastname: Petersson
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D059031:Anticipation, Psychological / Q000502:physiology*; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D003071:Cognition / Q000502:physiology*; D004569:Electroencephalography; D005074:Evoked Potentials, Visual; D005260:Female; D006801:Humans; D008297:Male; D011930:Reaction Time; D011932:Reading; D012660:Semantics; D013997:Time Factors; D014825:Vocabulary; D055815:Young Adult
keywords: Contextual congruency; Cross-modal verification; Electro-physiology; Event plausibility; Stimulus processing