Students are increasingly relying on Generative AI (GAI) to support their writing-a key pedagogical practice in education. In GAI-assisted writing, students can delegate core cognitive tasks (e.g., generating ideas and turning them into sentences) to GAI while still producing high-quality essays. This creates new challenges for teachers in assessing and supporting student learning, as they often lack insight into whether students are engaging in meaningful cognitive processes during writing or how much of the essay's quality can be attributed to those processes. This study aimed to help teachers better assess and support student learning in GAI-assisted writing by examining how different writing behaviors, especially those indicative of meaningful learning versus those that are not, impact essay quality. Using a dataset of 1,445 GAI-assisted writing sessions, we applied the cutting-edge method, X-Learner, to quantify the causal impact of three GAI-assisted writing behavioral patterns (i.e., seeking suggestions but not accepting them, seeking suggestions and accepting them as they are, and seeking suggestions and accepting them with modification) on four measures of essay quality (i.e., lexical sophistication, syntactic complexity, text cohesion, and linguistic bias). Our analysis showed that writers who frequently modified GAI-generated text-suggesting active engagement in higher-order cognitive processes-consistently improved the quality of their essays in terms of lexical sophistication, syntactic complexity, and text cohesion. In contrast, those who often accepted GAI-generated text without changes, primarily engaging in lower-order processes, saw a decrease in essay quality. Additionally, while human writers tend to introduce linguistic bias when writing independently, incorporating GAI-generated text-even without modification-can help mitigate this bias.

翻译：学生日益依赖生成式人工智能（GAI）辅助写作——这是教育中的一项关键教学实践。在GAI辅助写作中，学生可将核心认知任务（如生成观点并将其转化为句子）委托给GAI，同时仍能产出高质量文章。这给教师评估与支持学生学习带来了新挑战，因为他们往往难以洞察学生在写作过程中是否参与了有意义的认知活动，或文章质量在多大程度上可归因于这些认知过程。本研究通过考察不同写作行为（特别是有意义学习行为与非学习行为）对文章质量的影响，旨在帮助教师更好地评估与支持GAI辅助写作中的学生学习。基于1,445次GAI辅助写作会话数据集，我们采用前沿的X-Learner方法，量化了三种GAI辅助写作行为模式（即寻求建议但不采纳、寻求建议并原样采纳、寻求建议并修改后采纳）对四项文章质量指标（即词汇复杂度、句法复杂性、文本连贯性与语言偏见）的因果影响。分析表明，经常修改GAI生成文本的写作者——这暗示其积极参与了高阶认知过程——在词汇复杂度、句法复杂性和文本连贯性方面持续提升了文章质量。相反，那些经常不经修改直接采纳GAI生成文本、主要进行低阶认知活动的写作者，其文章质量出现下降。此外，尽管人类作者在独立写作时易引入语言偏见，但融入GAI生成文本——即使未经修改——也有助于缓解这种偏见。