Comment: Comment to: Melamed, D., Harrell, A., Simpson, B. (2018). Cooperation, clustering, and assortative mixing in dynamic networks. Proc Natl Acad Sci USA, 201715357Melamed, Harrell, and Simpson have recently reported on an experiment which appears to show that cooperation can arise in a dynamic network without reputational knowledge, i.e., purely via dynamics [1]. We believe that their experimental design is actually not testing this, in so far as players do know the last action of their current partners before making a choice on their own next action and subsequently deciding which link to cut. Had the authors given no information at all, the result would be a decline in cooperation as shown in [2].