title: Auditory semantic processing in dichotic listening: effects of competing speech, ear of presentation, and sentential bias on N400s to spoken words in context.
abstract: The effects of ear of presentation and competing speech on N400s to spoken words in context were examined in a dichotic sentence priming paradigm. Auditory sentence contexts with a strong or weak semantic bias were presented in isolation to the right or left ear, or with a competing signal presented in the other ear at a SNR of -12 dB. Target words were congruent or incongruent with the sentence meaning. Competing speech attenuated N400s to both congruent and incongruent targets, suggesting that the demand imposed by a competing signal disrupts the engagement of semantic comprehension processes. Bias strength affected N400 amplitudes differentially depending upon ear of presentation: weak contexts presented to the le/RH produced a more negative N400 response to targets than strong contexts, whereas no significant effect of bias strength was observed for sentences presented to the re/LH. The results are consistent with a model of semantic processing in which the RH relies on integrative processing strategies in the interpretation of sentence-level meaning.
authors.affiliation: Centre for Brain and Cognitive Development, Birkbeck College, University of London, United Kingdom. Electronic address: d.carey@bbk.ac.uk.
authors.forename: Daniel
authors.initials: D
authors.lastname: Carey
authors.affiliation: Institute of Cognitive Neuroscience, University College London, United Kingdom.
authors.forename: Evelyne
authors.initials: E
authors.lastname: Mercure
authors.affiliation: Centre for Brain and Cognitive Development, Birkbeck College, University of London, United Kingdom.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Pizzioli
authors.affiliation: Centre for Brain and Cognitive Development, Birkbeck College, University of London, United Kingdom.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Aydelott
mesh_terms: D000328:Adult; D032882:Comprehension / Q000502:physiology; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012660:Semantics; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult
keywords: Competing speech; Dichotic sentence processing; Lateralisation; N400; Semantic bias