I will first discuss how social interactions organize, coordinate, and specialize as "artifacts," tools; how these tools are not only for coordination but for achieving something, for some outcome (goal/function), for a collective work. In particular, I will argue that these artifacts specify (predict and prescribe) the mental contents of the participants, both in terms of beliefs and acceptances and in terms of motives and plans. We have to revise the behavioristic view of "scripts" and "roles"; when we play a role we wear a "mind." No collective action would be possible without shared and/or ascribed mental contents. This is also very crucial for a central form of automatic mind-reading (mind ascription). Second, I will argue that often what really matters is the ascribed/prescribed, worn, mind not the real, private one. We have to play (like in the symbolic play) "as if" we had those mental contents. This social convention and mutual assumption makes the interaction work. The ascribed beliefs and goals are not necessarily explicitly there; they might be just implicit as inactive (we act just by routine and automatically) or implicit as potential. The coordination and social action works thanks to these "as if" (ascribed and pretended) minds, thanks to those conventional constructs. Our social minds for social interactions are coordination artifacts and social institutions.