<p>Discussion has become a crucial method of interactive learning in online collaborative environments. This study aims to identify the impact of different task motivation compositions and learning scaffolding on attention, learning performance, and behavioral patterns. The 90 Chinese undergraduate and graduate students (M_age=20.38, SD_age=1.63) were told that they would be engaged in an online collaborative knowledge-building task with a virtual peer and a teacher. The peer and the teacher were actually simulated participant and their responses were pre-set. ANOVA results indicated that task motivation, but not learning scaffolding, had a significant effect on attention. Task motivation and learning scaffolding interactively accounted for learning performance. Furthermore, the result of mediation analysis shows that the association between task motivation and learning performance was mediated by attention, but the indirect effects of all the mediating variables were not significant between learning scaffolding and learning performance. In addition, students’ deep knowledge construction behavior in online discussion increased significantly in the conceptual and reflective scaffold conditions compared to just providing conceptual scaffolding irrespective of task motivation. These results suggest that although learning scaffolding does not significantly improve learners’ visual attention, the contribution of learning scaffolds to online discussion cannot be neglected. The practical implications of this study for online education are that learning scaffolding, especially reflective scaffolding, should be provided as a way to engage learners in productive, difficult conversations and improve the quality of their discussions in addition to enhancing task motivation.</p>