Previous research on the effect of task complexity on L2 writing performance has been mostly concerned with independent writing, and there is a paucity of empirical findings on integrated writing tasks in this regard. Thus, the present research investigated the impact of multiple-document integration on source-based writing. Two groups, with comparable general language proficiency, independent writing ability, and integrated writing ability participated in this research. In the simple task, the students were supposed to summarise a single text, whereas the participants in the complex task were asked to write a summary for a three-passage text dealing with the same issue, which was more cognitively taxing. The results revealed that task complexity had a significant impact on some measures of syntactic complexity (mean length of clause, subordination, and mean number of modifiers per noun phrase), lexical diversity, and causal cohesion, had an adverse influence on accuracy, and had no significant effect on lexical sophistication. The implications of these findings for L2 writing research and pedagogy are offered.

先前关于任务复杂性对第二层写作表现的影响的研究主要与独立写作有关，在这方面，关于综合写作任务的经验研究很少。因此，本研究调查了多文档集成对基于源代码的写作的影响。两组具有相同的一般语言水平，独立写作能力和综合写作能力的小组参加了这项研究。在简单的任务中，学生应该总结一个文本，而在复杂的任务中，参与者被要求为处理同一问题的三段式文本写一个摘要，这在认知上是比较费力的。结果表明，任务复杂度对某些语法复杂度的度量有显着影响（子句的平均长度，从属，以及每个名词短语的修饰语平均数），词法多样性和因果衔接，对准确性产生不利影响，对词法复杂度没有显着影响。这些发现对第二语言写作研究和教学法的启示。