在数字化经济时代，伴随疫情的冲击，越来越多教学活动大规模地由线下“搬运”到了线上，这极大推动了线上教学和数字化教育的发展，同时也暴露出线上教学的一些不足。在不同形式的在线教学活动中，录播课是被广泛采用的线上教学模式之一。录播课有诸如学习不受时间限制，可以共享优质资源等很多优点，但也被诟病存在诸如互动性差，趣味性不足等一些弊端。如何提高录播课中学习者的学习效果也成为研究者关注的焦点问题。

特别的，弹幕被认为在改进录播课学习效果方面存在着巨大潜力，但有关其效果的评价以及优化的手段仍缺乏系统研究。对于学生来说，使用弹幕能否有助于提升录播课的学习效果？如果有影响，其影响的内在机制又是什么呢？回答上述问题，对于以弹幕为抓手改进在线录播课教学质量至关重要。基于此，本研究基于问卷调查的资料、描述了初中生录播课和弹幕的使用现状，基于实验研究和比较研究的设计探究了使用弹幕对学习者形成性和终结性学习效果的影响，基于访谈资料剖析了优化弹幕设计、提升在线录播课教学效果的手段。研究主要得出以下结论：

第一，大多数学生都会利用录播课开展学习。从录播课的使用现状来看，样本初中生多数都学习过线上录播课并且使用过弹幕，使用的设备以移动端（如手机、ipad等）为主，这比较符合录播课随时随地进行学习的特点。多数学生选择bilibili和国家中小学智慧教育平台进行录播课学习并认为录播课可以满足学习需求。

第二，多数学生会在录播课使用过程中发送弹幕，且弹幕对于学习效果的提升有一定成效。从弹幕使用现状来看，多数学生使用并发送过弹幕。仅有极个别样本认为弹幕对学习存在负向影响，大部分学生认为使用弹幕能够促进主动思考、帮助识别课程重难点。从弹幕对学习过程的影响来看，使用弹幕对社会存在感和学习兴趣均无显著影响。从弹幕对学习成果的影响来看，使用弹幕对学生的保持成绩没有显著影响，但对学生的迁移成绩有显著的正向影响。

第三，教师与学生对于录播课的使用体验并不一致，弹幕的效果有待提升。从录播课使用体验来看，学生更关注上课的方式和内容，教师则更关注课堂管理的监管性。从弹幕使用体验来看，使用弹幕时学习者的社会存在感有提升，但这种提升有限，无法达到到线下课的水平。

第四，弹幕的“知识性”能提升学习兴趣，“丰富性”能启发思考。弹幕对学习者学习兴趣的影响来源于认知需求的满足，而弹幕的趣味性不能直接促进学习者的学习兴趣。录播课中的学习内容已经足以满足学习者的记忆与保持，所以使用弹幕对学习的保持成绩影响有限。而使用弹幕更有利于学习的迁移，因为弹幕中丰富多元的内容为学生提供了思维发散和启发思考的可能性，促进了学习者对知识的运用与迁移。

基于以上研究结论，本研究认为要发挥弹幕丰富多元内容的优势促进在线录播课中学习者的思考与知识迁移，并且可以通过改进弹幕的使用方式增强在线录播课中的互动交流、提升学习者学习兴趣。因此，本文认为应从弹幕的使用方式、内容呈现、把控质量等方面进行改进和优化并给出如下建议：

个性化筛选弹幕内容。录播课学习平台中可加入更多的个性化弹幕观看选项，便于学习者自由掌控弹幕的呈现内容与呈现时机，形成自适应的弹幕个性化使用模式。

有调控的弹幕使用。教师可通过弹幕预设重难点注释、提问或拓展帮助学习者加工录播课中的重要信息。弹幕的使用方式上亦需要教师的调控，如教师可以设置权限开放或关闭弹幕的发送，引导学生发送弹幕进行讨论互动，通过点评弹幕给予以学生激励和情感支持。

智能化的弹幕反馈。引入对弹幕的智能评价机制，通过设置弹幕的“点赞、点踩、举报”等功能保留录播课中高质量的弹幕内容，删除低质量无用的弹幕内容。此外，可对弹幕进行数据挖掘，分析文本特点和课程学习者的群体特点，从而对弹幕内容进行智能的反馈和干预。

In the era of digital economy, with the impact of the COVID-19 pandemic, more and more teaching activities have been moved from offline to online, which has greatly promoted the development of online teaching and digital education, but also exposed some shortcomings of online teaching. Among different forms of online teaching activities, recorded lectures are widely used. They have many advantages, such as learning without time restrictions and sharing high-quality resources, but they are also criticized for some drawbacks, such as poor interactivity and lack of interest. How to improve the learning effect of learners in recorded lectures has become a key issue for researchers.

In particular, danmaku, which refers to scrolling comments that overlay the video, is considered to have great potential for improving the learning effect of recorded lectures, but systematic research on its effectiveness and optimization methods is still lacking. Can using danmaku help improve the learning effect of recorded lectures for students? If so, what is the internal mechanism of its impact? Answering these questions is crucial for improving the teaching quality of online recorded lectures based on danmaku.

Based on questionnaire data, this study describes the current use of recorded lectures and danmaku among middle school students, explores the impact of using danmaku on learners' formative and summative learning effects through experimental and comparative studies, and analyzes the means of optimizing danmaku design and improving the effectiveness of online recorded lectures based on interview data. The study draws the following conclusions:

First, most students use recorded lectures for learning. Based on the use of recorded lectures, most middle school students in the sample have learned online recorded lectures and used danmaku, and they mainly use mobile devices (such as mobile phones and iPads), which is in line with the characteristics of anytime, anywhere learning of recorded lectures. Most students choose Bilibili and the National Primary and Secondary School Smart Education Platform for recorded lecture learning and believe that recorded lectures can meet their learning needs.

Second, most students send danmaku during the use of recorded lectures, and danmaku has a certain effect on improving the learning effect. Based on the use of danmaku, most students use and send danmaku. Only a few samples believe that danmaku has a negative impact on learning. Most students believe that using danmaku can promote active thinking and help identify the key points of the course. Regarding the impact of danmaku on the learning process, using danmaku has no significant impact on social presence and learning interest. Regarding the impact of danmaku on learning outcomes, using danmaku has no significant impact on students' maintained grades, but has a significant positive impact on students' transfer grades.

Third, teachers and students have different experiences in using recorded lectures, and the effect of danmaku needs to be improved. Based on the use of recorded lectures, students are more concerned about the way and content of the class, while teachers are more concerned about the supervisory management of the class. Based on the use of danmaku, the social presence of learners is improved, but the improvement is limited and cannot reach the level of offline classes.

Fourth, the "knowledge" of danmaku can enhance learning interest, and the "richness" of danmaku can inspire thinking. Danmaku should be designed based on the characteristics of the course and students, such as the course difficulty, learning objectives, and cognitive level of students.

Based on the research conclusions above, this study believes that leveraging the advantages of danmaku to provide diverse content can promote learners' thinking and knowledge transfer in online recorded courses. Improving the use of danmaku can also enhance interactive communication and increase learners' interest in learning. Therefore, this article proposes the following suggestions for improving and optimizing the use of danmaku in online recorded courses, including:

Firstly, personalized filtering of danmaku content. More personalized options for danmaku viewing can be added to the learning platform to enable learners to control the content and timing of the danmaku presentation, creating an adaptive danmaku personalized use model.

Secondly, regulated use of danmaku. Teachers can use danmaku to annotate difficult points, ask questions or provide additional information to help learners process important information in recorded courses. The use of danmaku also requires regulation by the teacher, such as setting permissions to enable or disable the sending of danmaku, guiding students to discuss and interact through danmaku, and providing students with encouragement and emotional support through feedback on danmaku.

Thirdly, intelligent danmaku feedback. An intelligent evaluation mechanism for danmaku can be introduced, allowing the preservation of high-quality danmaku content and deletion of low-quality and useless content through functions such as "like," "dislike," and "report." In addition, data mining of danmaku can be conducted to analyze the text characteristics and demographic characteristics of course learners, providing intelligent feedback and intervention for danmaku content.