发表机构
Questrom School of Business, Boston University（波士顿大学奎斯特罗姆商学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过随机田野实验分离教学结构与交互模态，发现结构化AI辅导显著提升学习效果（+6.63分），而语音模态虽增加交互却未影响学习，表明教学结构而非类人化决定教育成效。
AI 中文摘要
学生越来越多地与生成式人工智能（AI）一起学习，然而，无指导地获取流畅答案会诱发认知卸载，并且关于哪种AI辅导配置能产生学习效果，证据甚少。两个设计维度通常被捆绑在一起：教学结构（导师如何教学）和交互模态（学生如何与它对话）。我们将二者分离。在一项预先注册的随机田野实验中，我们针对在线MBA研究生公司金融课程，将86名学生随机分配到两组：一组使用基于课程材料的结构化导师，另一组为对照组，其中消费级AI仍可自由使用。在辅导组内，每个学生的交流渠道在语音和文本之间每周交替，因此模态效应是在学生内部识别的。结构很重要：接受辅导的学生比能力匹配的同伴多获得6.63分（p=.007），且收益集中在书面推理上，其中达到关系质量的答案比例在辅导组从8%升至49%，而对照组从8%升至27%。模态对学习没有影响。教师自己的期末考试（所有86名随机学生均有记录）显示出相同的方向（满分100分中高出2.6分，而在治疗前的期中考试中无差异）。语音使对话交互几乎翻倍，且交付成本是文本的2.8倍，然而它产生的每周掌握程度在统计上与文本相当，即使学生逐渐更偏好语音。教学结构塑造学生练习的内容，而模态塑造他们与导师互动的方式。让AI更类人并不会自动使其更具教育性。
英文摘要
Students increasingly study alongside generative artificial intelligence (AI), yet unguided access to fluent answers invites cognitive offloading, and there is little evidence on which configurations of AI tutoring produce learning. Two design margins are usually bundled together: pedagogical structure (how the tutor teaches) and interaction modality (how students talk to it). We separate them. In a preregistered randomized field experiment in a graduate corporate-finance course of an online MBA, we randomized 86 students between a structured tutor grounded in the course materials and a holdout in which consumer AI remained freely available. Within the tutored arm, each student's channel alternated weekly between voice and text, so the modality effect is identified within student. Structure mattered: tutored students gained 6.63 points more than ability-matched peers (p=.007), and the gain was concentrated in written reasoning, where the share of answers reaching relational quality rose from 8% to 49% in the tutored arm against 8% to 27% in the holdout. Modality did not matter for learning. The instructor's own final, on file for all 86 randomized students, shows the same direction (2.6 points of 100, with no difference on a pre-treatment midterm). Voice nearly doubled conversational interaction and cost 2.8 times as much to deliver, yet it produced weekly mastery statistically equivalent to text, even as students came to prefer it. Pedagogical structure shapes what students practice, and modality shapes how they interact with the tutor. Making an AI more humanlike does not by itself make it more educational.
