In this paper I identify the “infrastructure model” as the predominant approach to computationally mediated participatory design from the 1960s until the present, and discuss its history, conceptual underpinnings, and limitations. As case studies for this analysis, I use the French-based architect Yona Friedman’s and the MIT Architecture Machine Group’s 1970s proposals for participatory design computational systems. I employ the polysemic notion of “performance” to interrogate the two systems in three levels: What rationale supports the authors’ claims that in order for design to well perform for its future users, it should be performed by them? What computational models are developed to enable users to perform their own designs? How can performance, as an intuitive, improvisational process, be used to criticize the traditional models of computation in design participation and devise new computational agendas?