Cooperation is the foundation of society, but we still know little about the conditions under which cooperation spreads within a group.We analyze cooperation in multiplex networks, which have recently gained attention as a model that successfully captures certain aspects of human social connections.Previous studies have shown that symmetry between interactions and strategy replacements promotes cooperation across a wide range of network structures, including regular networks, scale-free networks, and weighted dynamic networks.Interactions refer to actions that cause increases or decreases in payoff, and strategy replacements refer to actions that cause changes in behavioral traits.When these two actions are performed with the same partner as much as possible, we call the situation symmetrical.In other words, prior research indicates that in a two-layer multiplex network, where the first layer constrains the choice of interaction partners and the second layer constrains the choice of replacement partners, the more similar the two layers are, the more likely cooperation is promoted.However, we focus on the difference in scope between the two actions and, contrary to previous studies, find cases in which asymmetry promotes cooperation.This indicates that there can be not only symmetric but also asymmetric approaches for promoting cooperation.