Effects of Task-Irrelevant Talker Identity and Continuity on Spatial Selective Attention Under Interruption

Task-irrelevant features can impact formation of auditory objects and influence the effectiveness of selective attention, including the buildup of attention over time. Using a previously established paradigm exploring the effects of random interruptions on spatial selective attention, this study explores how the task-irrelevant feature of talker identity impacts the buildup of spatial attention and whether it alters the impact of interruptions. Participants performed a sequence recall task in which participants were presented with two competing syllable sequences coming from different spatial directions and were asked to report the syllable sequence coming from the target direction. On half of the trials, an unpredictable, novel interrupting sound occurred, disrupting attentional focus. Two experiments explored how talker identity influenced performance, specifically, whether 1) making the two streams come from different talkers facilitates task performance and reduces the impact of interruption compared to when the streams are spoken by the same talker, and 2) talker discontinuity interferes with attention buildup and harms syllable recall performance compared to when the talker is the same from one syllable to the next. Our results showed that distinct talker features, though task-irrelevant in this spatial task, significantly improved syllable recall performance and reduced the impact of interrupters. Further, irrelevant talker discontinuities damaged attention buildup and reduced syllable recall performance. Post hoc analysis also revealed that repeating syllables in sequence substantially improved recall performance, which should be accounted for in future studies using similar paradigms.