The purpose of this study is to explore how student competition using the tit-for-tat strategy could be remedied with a minimum design change in order to support student to collaborate constructively in a computer supportedcollaborative learning system called SWoRD (Scaffolded Writing and Reviewing in the Discipline) [5], a reciprocal peer reviewing of writing system. We identified a factor for the tit-for-tat that causes learners to compete each other, and removed the factor from the interface. The results show when with the interface improvement the tit-for-tat strategy was restrained in the SWoRD system, which helped the learners constructively respond to peer comments.