在线学习具有线下面对面学习无法比拟的优势，然而在线学习的实践中面临着一些问题，包括学习者自觉性低、自学能力薄弱、情感上孤独倦怠、在线资源内容良莠不齐、教师激励和引导缺失等，使得学生的学习目标达成率低，学习效率低下，通过在线教育的实践使得研究者们对其理论研究要求更高。学生在学习中投入的时间和精力（学生投入度）对学习结果具有重大影响。学生投入度是一个复杂的动态系统，与其影响因素之间的关系是非线性的。本文意欲研究在线讨论学习中，学生投入度的非线性变化过程，以及相关因素对这个变化过程的影响。

本研究以动态系统理论为理论基础，首先综述了前人的相关研究内容和研究结果，确定了每个研究变量的测量方式。然后将某高校《普通心理学》基础课中的42名学生作为研究对象，探究了在在线讨论的情境下，大学生学生投入度的三个维度的动态变化过程；学生的自我效能感、幸福感和大五人格对学生投入度的变化的影响；以及内容反馈和社交反馈两种教师反馈形式对学生的投入度的影响。

研究的主要发现有：首先，在一个学期内，学生的情感投入度较为稳定，学生的行为投入度受到情绪和自我效能感等因素的影响波动较大；其次，学生的积极情绪、消极情绪和大五人格，以及自我效能感会影响学生每周的学生投入度；最后，在异步在线讨论的情境下，教师的内容反馈比社交反馈更能提升学生投入度；与教师的交流互动会显著增强学生的幸福感和学习参与。

Online learning has incomparable advantages compared with offline and face-to-face education. However, there are some problems in the practice of online learning, including learners' low self-consciousness, weak self-learning ability, emotional loneliness, uneven online resources, lack of teachers' motivation and guidance, which make students' learning goal achievement rate low and learning efficiency low. It makes researchers have higher requirements for their theoretical research. The amount of time and energy that students invest in their studies has a great influence on the learning results. Student engagement is a complex dynamic system, and the relationship between it and its influencing factors is nonlinear. This paper intends to study the nonlinear change process of students' engagement in online discussion learning and the influence of related factors on this change process.

Based on dynamic systems theory, this study first reviewed the relevant previous studies and research results, and determined the measurement of each research variable. Then 42 students in a basic course of General Psychology at a university were used as the study participants. The dynamic change process of the three dimensions of college students' engagement was explored in the context of online discussions; the effects of students' self-efficacy, well-being, and Big Five personality on the changes of students' engagement; and the effects of two forms of instructor feedback, content feedback and social feedback, on students' engagement and performance.

      The main findings of the study are as follows: firstly, students' emotional engagement is relatively stable over the course of a semester while students' behavioral engagement is more fluctuated and depending on factors such as mood and self-efficacy. Secondly, students' positive emotions, negative emotions, big five personalities, and self-efficacy affect students' weekly engagement. Finally, in the context of asynchronous online discussions, content feedback from the instructor enhances student engagement more than social feedback. The direct interaction with teachers can significantly enhance students' happiness and learning participatio