随着在线学习在教育领域的兴起，在线教育平台逐步进入大众视野，利用在线视频进 行学习的人数也日益增多。弹幕是一种依附于视频而存在的帮助用户完成实时互动的工具， 因其具有匿名性、强互动性、即时性等特点而受到广泛欢迎。目前已有研究者对弹幕在线 上教学场景中的应用进行研究，但考虑到不同类型认知风格学习者在学习策略、行为偏好 等方面会存在差异，因此本研究进一步深化弹幕在线上教学场景中的研究，探究在线上视 频教学平台中，不同认知风格学习者对弹幕的使用行为及态度差异，并针对不同认知风格 学习者学习习惯对当前线上视频教学平台进行弹幕功能的优化升级，以达到提高学习者线 上学习体验和学习效果的目的，从而促进在线教育的良好发展。

本研究分为三个阶段，分别是用户研究阶段、设计转化阶段和设计评估阶段。

在用户研究阶段，本研究通过问卷调查证实了不同认知风格学习者在线上学习过程中 在行为与态度上存在差异，以及不同认知风格学习者在线上教学场景下对于弹幕的使用行 为与态度也存在差异。随后通过用户访谈，得到不同认知风格学习者行为态度差异背后的 深层次心理动因，用户当前在线上学习场景下对于弹幕使用存在的痛点需求。基于访谈结 果提出针对弹幕的五个设计优化策略，分别是提高弹幕质量、优化弹幕互动方式、优化弹 幕呈现方式、增加教学辅助功能与提供一定情感支持。

在设计转换阶段，围绕这五点设计策略在后续进行了进一步的产品优化设计。本研究 以北京师范大学数字京师畅课平台为基础，为其增加了弹幕相关功能，并针对不同类型认 知风格学习者的需求分别进行设计转换。

在设计评估阶段，本研究通过 A/B 测试的方式，邀请不同认知风格学习者进行可用性 测试，收集用户对两款产品的可用性、满意度、认知负荷反馈，同时让评估者在平台上进 行视频学习，并通过知识测验评估学习者在不同平台的学习效果。从评估结果看，相比原 始平台，增加弹幕功能后的优化平台在产品可用性方面和学习效果方面高于原始平台，验 证了弹幕设计策略具备较好的有效性和可行性，且能够一定程度提高学生的学习效果。但 其认知负荷上要高于原始平台，可能会对学习者的学习过程造成负担。针对增加弹幕功能 的优化后教学平台，本研究进一步从产品可用性、满意度、认知负荷及学习效果四个方面 比较两种认知风格学习者之间的差异，结果表明场依存认知风格学习者在用户满意度和认 知负荷两方面的评价均高于场独立学习者。

With the rise of online learning in the field of education, online education platforms have gradually entered the public eye, and the number of people using online videos for learning is also increasing. Bullet screen is a tool attached to video to help users complete real-time interaction. It is widely welcomed because of its anonymity, strong interaction, instantaneity and other characteristics. At present, researchers have conducted research on the application of bullet screen in online teaching scenes, but considering that different types of cognitive style learners will have differences in learning strategies, behavioral preferences, etc., this study further refines the research in bullet screen online teaching scenes, and explores the differences in the use behavior and attitude of different cognitive style learners to bullet screen in online video teaching platforms, And according to the learning habits of learners with different cognitive style, the pop-up function of the current online video teaching platform is optimized and upgraded to improve learners' online learning experience and learning effect, so as to promote the good development of online education.

This study is divided into three stages: user research stage, design transformation stage, and design evaluation stage.

In the user research phase, the researcher confirmed that there are differences in the behavior and attitude of learners with different cognitive style during online learning through questionnaires, and there are also differences in the behavior and attitude of learners with different cognitive style for the use of bullet screens in online teaching scenarios. Then, through user interviews, we got the deep psychological motivation behind the differences in the behavior and attitude of learners with different cognitive style. Users' pain points for the use of bullet screens in the current online learning scene. Based on the interview results, we proposed five design optimization strategies for bullet screens, namely, improving the quality of bullet screens, optimizing the interaction mode of bullet screens, optimizing the presentation mode of bullet screens, increasing the auxiliary teaching functions and providing some emotional support.

In the design transformation phase, further product optimization design was carried out around these five design strategies in the future. This research is based on the Beijing Normal University Digital Jingshi Chang Class Platform, which adds bullet screen related functions to it, and is designed for the needs of different types of cognitive style learners.

In the design evaluation phase, this study invited learners with different cognitive style of field independence/field dependence to conduct usability tests through A/B tests, collect users' feedback on the usability, satisfaction and cognitive load of the two products, and let the evaluators conduct video learning on the platform, and evaluate learners' learning effects on different platforms through knowledge tests. From the evaluation results, it can be seen that compared to the original platform, the optimized platform with added bullet screen function has higher product availability and learning effectiveness than the original platform, verifying that the bullet screen design strategy has good effectiveness and feasibility, and can improve students' learning effectiveness to a certain extent. But in terms of cognitive load, it is higher than the original platform. For the optimized teaching platform with the added pop-up function, this study further compares the differences between the two cognitive style learners from four aspects: product availability, satisfaction, cognitive load and learning effect. The results show that field dependent cognitive style learners have higher evaluations of user satisfaction and cognitive load than field independent learners.