Abstract Although bilingual children and elderly have been observed to outperform monolinguals in typical executive control tasks, this bilingual advantage is not consistently found in the young adult population. Proponents of the bilingual executive control advantage argue the reason for this is that task demands in the typical tasks used are not high enough, since young adults perform at ceiling level, whereas critics of the effect argue it has benefited from publication bias. Here we test the task-load hypothesis using a standard and a difficult version of the arrow-flanker task and identify stimulus processing characteristics underlying greater bilingual executive control. We increased task demands by using an “Opposite” task in which participants were to respond to the central arrow indicating its opposite direction whilst a task cue indicated which task was to be performed at each trial. Further increase in task difficulty was expected to arise from reducing the task preparation time by using different stimulus-onset-asynchronies between cue and target stimuli. As predicted, we observed no language group differences in the normal flanker task, whereas bilinguals displayed less errors than monolinguals and were less hampered by the difficult task than monolinguals when auditory task cues were used. Event-related potentials (ERPs) revealed that the bilinguals' conflict monitoring response occurred much earlier than the monolinguals’ when the task cue was auditory but less so when the cue was visual. Indeed, bilinguals appeared to prioritize the cue signal when it was auditory, but not when it was visual. Further ERP results showed bilinguals displayed greater attentional responses to the target stimulus than monolinguals. Finally, the behavioral and conflict-monitoring ERP responses correlated with language proficiency and usage scores. Together, these results show that when tasks demands are high and auditory processing is part of the task, bilingual adults outperform monolinguals due to better stimulus identification and greater efficiency in managing task demands.

中文翻译：

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听觉处理和高任务要求促进了年轻人的双语执行控制优势

摘要 虽然双语儿童和老年人在典型的执行控制任务中被观察到优于单语者，但这种双语优势并没有在年轻成年人群中持续发现。双语执行控制优势的支持者认为，其原因是所使用的典型任务中的任务要求不够高，因为年轻人的表现处于天花板水平，而对该效应的批评者则认为它受益于发表偏见。在这里，我们使用箭头侧翼任务的标准和困难版本来测试任务负载假设，并确定更大的双语执行控制背后的刺激处理特征。我们通过使用“相反”任务来增加任务需求，在该任务中，参与者将对指示其相反方向的中央箭头做出反应，而任务提示则指示在每次试验中要执行的任务。通过在提示和目标刺激之间使用不同的刺激开始异步来减少任务准备时间，预计会进一步增加任务难度。正如预测的那样，我们在正常的侧翼任务中没有观察到语言组的差异，而双语者比单语者显示出更少的错误，并且在使用听觉任务线索时比单语者更少受到困难任务的阻碍。事件相关电位 (ERP) 显示，当任务线索是听觉的时，双语者的冲突监控反应比单语者的发生得早得多，而在视觉线索时则更少。确实，双语者似乎优先考虑听觉提示信号，而不是视觉提示信号。进一步的 ERP 结果显示，双语者比单语者对目标刺激表现出更大的注意力反应。最后，行为和冲突监测 ERP 反应与语言能力和使用分数相关。总之，这些结果表明，当任务要求很高并且听觉处理是任务的一部分时，双语成年人的表现优于单语者，因为更好的刺激识别和更高的管理任务需求的效率。行为和冲突监测 ERP 反应与语言能力和使用分数相关。总之，这些结果表明，当任务要求很高并且听觉处理是任务的一部分时，双语成年人的表现优于单语者，因为更好的刺激识别和更高的管理任务需求的效率。行为和冲突监测 ERP 反应与语言能力和使用分数相关。总之，这些结果表明，当任务要求很高并且听觉处理是任务的一部分时，双语成年人的表现优于单语者，因为更好的刺激识别和更高的管理任务需求的效率。