This study examined the independent effects of working memory (WM) and the interactive effects of WM/L2 proficiency and WM/task complexity on L2 written performance. The study followed a within–between-participant factorial design, with two levels of task complexity as the within-participant variable and L2 proficiency and WM as between-participants variables. The outcome measure was L2 writing performance as measured by CAF indices. Two groups of undergraduate students from a degree in English studies were invited to complete the simple and complex version of the “Fire-Chief” task. Task complexity was operationalized in terms of reasoning demands, and tasks were counterbalanced to avoid unwanted order effects. Participants also completed the Oxford Placement Test and a working memory test (n-back). Regarding independent effects, results show that WM did not have an effect on L2 writing performance. In contrast, L2 proficiency was the variable most connected to various dimensions of the text produced. As for interactive effects, no significant interaction between WM, proficiency, or task complexity was found. In contrast, L2 proficiency emerged as the sole significant predictor of L2 writing performance at both levels of task complexity.

中文翻译：

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工作记忆、二语熟练程度和任务复杂性：对二语书面表现的独立和交互影响

本研究考察了工作记忆 (WM) 的独立影响以及 WM/L2 熟练程度和 WM/任务复杂性对 L2 书面表现的交互影响。该研究遵循参与者内部-参与者之间的因子设计，以两个级别的任务复杂性作为参与者内部变量，并将 L2 熟练程度和 WM 作为参与者之间变量。结果指标是通过 CAF 指数衡量的 L2 写作表现。两组英语研究专业的本科生被邀请完成简单版和复杂版的“消防队长”任务。任务复杂性根据推理需求进行操作，并平衡任务以避免不必要的顺序效应。参与者还完成了牛津分班测试和工作记忆测试（n-后退）。关于独立效应，结果表明 WM 对 L2 写作性能没有影响。相比之下，第二语言熟练程度是与所生成文本的各个维度最相关的变量。至于交互效应，没有发现 WM、熟练程度或任务复杂性之间存在显着的交互作用。相比之下，二语熟练程度成为在两个任务复杂程度级别上二语写作表现的唯一重要预测指标。