Involuntary attentional capture by speech and non-speech deviations: A combined behavioral–event-related potential study

Abstract

This study applied an auditory distraction paradigm to investigate involuntary attention effects of unexpected deviations in speech and non-speech sounds on behavior (increase in response time and error rate) and event-related brain potentials (ΔN1/MMN and P3a). Our aim was to systematically compare identical speech sounds with physical vs. linguistic deviations and identical deviations (pitch) with speech vs. non-speech sounds in the same set of healthy volunteers. Sine tones and bi-syllabic pseudo-words were presented in a 2-alternative forced-choice paradigm with occasional phoneme deviants in pseudo-words, pitch deviants in pseudo-words, or pitch deviants in tones. Deviance-related ERP components were elicited in all conditions. Deviance-related negativities (ΔN1/MMN) differed in scalp distribution between phoneme and pitch deviants within phonemes, indicating that auditory deviance-detection partly operates in a deviance-specific manner. P3a as an indicator of attentional orienting was similar in all conditions, and was accompanied by behavioral indicators of distraction. Yet smaller behavioral effects and prolonged relative MMN-P3a latency were observed for pitch deviants within phonemes relative to the other two conditions. This suggests that the similarity and separability of task-relevant and task-irrelevant information is essential for the extent of attentional capture and distraction.