Bouncing back: Transient, but not long-lasting, effects of background disturbances on speech processing

Abstract

Processing and understanding speech in face of occasional background disturbances can be difficult and often leads to distraction and reduced comprehension. However, despite the vast literature on the detrimental effects of processing speech-in-noise, little is known about the time-course of these effects. Here we studied whether reduced speech processing is limited only to the period when disruptions mask target speech, or if processing difficulties linger even after disruptions end, suggesting longer lasting distraction. Using an ecologically-relevant experimental design, we measured neural activity and skin-conductance from participants as they watched an educational video-lecture. Short background speech comments, mimicking plausible classroom disruptions, were occasional embedded in half of the lecture segments. Speech disruptions elicited robust neurophysiological orienting responses, reflected in a neural auditory ERP and a phasic increase in skin conductance. Importantly, when disruptions were presented, we observed a marked reduction in neural tracking of the lecture, increased inter-subject correlation (ISC), and decreased alpha power, suggesting a brief diversion of processing resources away from the target speech. However, these effects were transient in nature, with all neural measures returning to baseline immediately after disruption offset, showing no evidence for prolonged disruption-related costs or impaired comprehension. Interestingly, neurophysiological responses to disruption and return to baseline were not correlated with self-reported symptoms of attention-deficits (ADD). These findings highlight the resilience of auditory attention, demonstrating its ability to maintain a robust representations of target speech over time, despite of transient ecological disturbances.