This study, guided by Engestrom`s (1999, 2001) activity theory which owes its theoretical lineage to sociocultural theory, explores how roles (peer feedback givers and receivers) and tasks are distributed among EFL students who engage in peer response. More specifically, as an extension of previous research of focusing on "stances" ESL students adopt, I investigate whether different roles in peer response groups make a difference in the nature of peer response and identify what underlays the different roles in peer group interaction. In addition, I examine whether different roles to the peer response create tensions and contradictions in peer response and how these created conflicts lead to changes in peer response activity system. The data I wish to consider is first-person narratives elicited from two EFL college students. I use Won`s and Choi`s (both pseudonyms) stories as a heuristic, which is a method that allowing one to proceed fruitfully in finding information. Foregrounded in this study are the students` different roles in the same peer response activity. A division of labor exists between Won/Choi and their peers - the way tasks are divided up and the way roles are structured. Yet Won and Choi adopted rather divergent roles when participating in peer response activity and carried out qualitatively different peer response activities. It is obvious here that the distribution of their roles in carrying out this particular peer response is shaped by Won` and Choi`s perception about the validity of their peers` responses.