Replicating and Extending Hemispheric Asymmetries in Auditory Distraction: No Metacognitive Awareness for the Left-Ear Disadvantage for Changing-State Sounds

Two experiments explored hemispheric asymmetries in auditory distraction by manipulating the spatial location of presentation of to-be-ignored sound. Previous research revealed a left-ear disadvantage for the presentation of changing-state sequences during short-term serial recall (Hadlington et al., 2004; 2006), but did not provide a direct measure of the changing-state effect as no steady-state condition was incorporated. Experiment 1 addressed this by comparing changing-state with steady-state sequences in a visual-verbal serial recall task, and confirmed that the additional disruption produced via left-ear presentation stemmed from the acoustically varying nature of the sound. This left-ear disadvantage for the changing-state effect highlights right hemisphere dominance for processing acoustic variation within unattended sound. Using the same stimuli, Experiment 2 replicated these results and gained insight into participant’s metacognitive monitoring of the disruptive potential of auditory distractors. Participants prospectively rated the extent to which they would be distracted by steady-state and changing-state sequences presented to the left ear, right ear, or both ears, and judged whether the sounds had a beneficial or detrimental effect on their performance after each trial. Participants showed both prospective and retrospective awareness that changing-state sequences were more disruptive than steady-state sequences (cf. Bell et al., 2021). However, participants did not expect disruption to vary by auditory location and were unaware that changing-state sequences were more disruptive when presented to the left ear, relative to the right ear or both ears. Therefore, individuals have metacognitive awareness of the greater disruptive impact of changing- over steady-state sound, but not the accompanying left-ear disadvantage. Implications of these findings are considered in the context of theoretical accounts of auditory distraction.

两项实验通过操纵需要忽略的听觉刺激的呈现空间位置，探究了听觉分心（auditory distraction）效应中的半球不对称性（hemispheric asymmetries）。既往研究发现，在短时序列回忆（short-term serial recall）任务中，变化状态序列（changing-state sequences）的左耳呈现存在左耳劣势效应（Hadlington等人，2004；2006），但由于未设置稳态条件，未能直接量化变化状态效应的大小。实验1通过在视觉-言语序列回忆任务中对比变化状态序列与稳态序列（steady-state sequences），填补了这一研究空白，并证实左耳呈现所引发的额外干扰源于声音的声学变化特性。这种针对变化状态效应的左耳劣势，揭示了右半球在加工未被注意的声音的声学变化时占据主导地位。使用相同的刺激材料，实验2重复验证了上述结果，并深入探讨了被试对听觉分心刺激潜在干扰性的元认知监控（metacognitive monitoring）。被试会前瞻性地评估左耳、右耳或双耳呈现的稳态序列与变化状态序列对自身的分心程度，并在每轮试次后判断这些声音对自身任务表现产生的是有益还是有害影响。结果显示，被试表现出了前瞻性与回溯性的认知：变化状态序列比稳态序列更具干扰性（参照Bell等人，2021）。然而，被试并未预料到分心程度会随听觉呈现位置发生变化，也未意识到相较于右耳或双耳呈现，左耳呈现的变化状态序列会带来更强的干扰。因此，个体能够元认知到变化状态声音相较于稳态声音具有更强的干扰效应，但并未意识到与之伴随的左耳劣势效应。本研究结合听觉分心效应的相关理论框架，对上述发现的理论意义进行了探讨。