Kousaie Shanna, Phillips Natalie A
Cognitive Neuroscience Unit, Montreal Neurological Institute, McGill University, Canada.
Department of Psychology/Centre for Research in Human Development, Concordia University, Canada.
Neuropsychologia. 2017 Jan 8;94:23-35. doi: 10.1016/j.neuropsychologia.2016.11.013. Epub 2016 Nov 20.
Given previous, but inconsistent, findings of language group differences on cognitive control tasks the current investigation examined whether such differences could be demonstrated in a sample of older bilingual adults. Monolingual and bilingual older adults performed three cognitive control tasks that have previously been used in the literature (i.e., Stroop, Simon and flanker tasks) while brain electrophysiological recordings took place. Both behavioural (response time and accuracy) and event-related brain potentials (ERPs; N2 and P3 amplitude and latency) were compared across the two language groups. Processing differences between monolinguals and bilinguals were identified for each task, although the locus differed across the tasks. Language group differences were most clear in the Stroop task, with bilinguals showing superior performance both behaviourally and electrophysiologically. In contrast, for the Simon and flanker tasks there were electrophysiological differences indicating language group processing differences at the level of conflict monitoring (Simon task only) and stimulus categorization (Simon and flanker tasks), but no behavioural differences. These findings support suggestions that these three tasks that are often used to examine executive control processes show little convergent validity; however, there are clear language group differences for each task that are suggestive of superior performance for bilinguals, with behavioural differences emerging only in the linguistic Stroop task. Furthermore, it is clear that behavioural measures alone do not capture the language group effects in their entirety, and perhaps processing differences between language groups are more marked in a sample of older adults who are experiencing age-related cognitive changes than in younger adults who are at the peak of their cognitive capacity.
鉴于先前关于语言群体在认知控制任务上存在差异的研究结果并不一致，当前的调查研究了在一组老年双语成年人样本中是否能证实这种差异。单语和双语老年成年人在进行三项先前文献中使用过的认知控制任务（即斯特鲁普任务、西蒙任务和侧翼任务）时，同时进行脑电生理记录。对两个语言群体的行为指标（反应时间和准确性）以及事件相关脑电位（ERP；N2和P3波幅及潜伏期）进行了比较。尽管不同任务中差异的位点有所不同，但每项任务都发现了单语者和双语者之间的加工差异。语言群体差异在斯特鲁普任务中最为明显，双语者在行为和电生理方面均表现出更优的成绩。相比之下，在西蒙任务和侧翼任务中，存在电生理差异，表明在冲突监测水平（仅西蒙任务）和刺激分类（西蒙任务和侧翼任务）上存在语言群体加工差异，但行为上没有差异。这些发现支持了这样的观点，即这三项常用于检验执行控制过程的任务几乎没有聚合效度；然而，每项任务都存在明显的语言群体差异，表明双语者表现更优，且行为差异仅出现在语言斯特鲁普任务中。此外，很明显仅行为测量并不能完全捕捉语言群体效应，而且在经历与年龄相关认知变化的老年成年人样本中，语言群体之间的加工差异可能比处于认知能力巅峰的年轻成年人更为显著。
