Naylor Lavelda J, Stanley Emily M, Wicha Nicole Y Y
Department of Biology, University of Texas at San Antonio San Antonio, TX, USA.
Front Psychol. 2012 Apr 2;3:81. doi: 10.3389/fpsyg.2012.00081. eCollection 2012.
The color word Stroop effect in bilinguals is commonly half the magnitude when the written and naming languages are different (between) than when they are the same (within). This between-within language Stroop difference (BWLS) is likened to a response set effect, with greater response conflict for response relevant than irrelevant words. The nature of the BWLS was examined using a bilingual Stroop task. In a given block (Experiment 1), color congruent and incongruent words appeared in the naming language or not (single), or randomly in both languages (mixed). The BWLS effect was present for both balanced and unbalanced bilinguals, but only partially supported a response set explanation. As expected, color incongruent trials during single language blocks, lead to slower response times within than between languages. However, color congruent trials during mixed language blocks led to slower times between than within languages, indicating that response-irrelevant stimuli interfered with processing. In Experiment 2, to investigate the neural timing of the BWLS effect, event related potentials were recorded while balanced bilinguals named silently within and between languages. Replicating monolingual findings, an N450 effect was observed with larger negative amplitude for color incongruent than congruent trials (350-550 ms post-stimulus onset). This effect was equivalent within and between languages, indicating that color words from both languages created response conflict, contrary to a strict response set effect. A sustained negativity (SN) followed with larger amplitude for color incongruent than congruent trials, resolving earlier for between than within language Stroop. This effect shared timing (550-700 ms), but not morphology or scalp distribution with the commonly reported sustained potential. Finally, larger negative amplitude (200-350 ms) was observed between than within languages independent of color congruence. This negativity, likened to a no-go N2, may reflect processes of inhibitory control that facilitate the resolution of conflict at the SN, while the N450 reflects parallel processing of distracter words, independent of response set (or language). In sum, the BWLS reflects brain activity over time with contributions from language and color conflict at different points.
当双语者的书写语言和命名语言不同（跨语言）时，颜色词斯特鲁普效应的强度通常只有两者相同时（同语言）的一半。这种跨语言与同语言的斯特鲁普差异（BWLS）类似于一种反应定势效应，即与反应无关的单词相比，与反应相关的单词会产生更大的反应冲突。本研究使用双语斯特鲁普任务来探究BWLS的本质。在给定的组块中（实验1），颜色一致和不一致的单词要么以命名语言呈现（单一语言条件），要么随机以两种语言呈现（混合语言条件）。平衡型和非平衡型双语者都出现了BWLS效应，但仅部分支持反应定势解释。正如预期的那样，在单一语言组块中，颜色不一致的试验导致同语言内的反应时间比跨语言时更慢。然而，在混合语言组块中，颜色一致的试验导致跨语言的反应时间比同语言内更慢，这表明与反应无关的刺激干扰了加工过程。在实验2中，为了探究BWLS效应的神经时间进程，在平衡型双语者在同语言和跨语言条件下默读时记录事件相关电位。重复单语研究的结果，观察到N450效应，即颜色不一致试验的负波幅大于颜色一致试验（刺激开始后350 - 550毫秒）。这种效应在同语言和跨语言条件下是等效的，这表明两种语言的颜色词都会产生反应冲突，这与严格的反应定势效应相反。随后出现了持续负波（SN），颜色不一致试验的波幅大于颜色一致试验，并且跨语言斯特鲁普效应的持续负波比同语言斯特鲁普效应的持续负波更早消退。这种效应的时间进程相同（550 - 700毫秒），但形态或头皮分布与通常报道的持续电位不同。最后，无论颜色是否一致，跨语言条件下观察到的负波幅（200 - 350毫秒）都大于同语言条件。这种负波类似于“不执行”N2，可能反映了抑制控制过程，该过程有助于在SN阶段解决冲突，而N450反映了干扰词的并行加工，与反应定势（或语言）无关。总之，BWLS反映了大脑活动随时间的变化，不同阶段受到语言和颜色冲突的影响。
