The housing cluster appears in architect Christopher Alexander’s writing as an architectural form that responds to and influences social engagement. In the 1970s, prioritizing the needs and perspectives of people—through group participation, common decision-making, and sharing of resources—aimed to elevate the common good. The cluster form was seen as a container for these activities.¹ In the book A Pattern Language (1977), Alexander juxtaposes the housing cluster against tract housing, popular suburban developments of similar mass-produced homes built on large tracts or subdivisions of land. He cites observations made by sociologist Herbert Gans, who lived in a tract housing development and noted that his neighbors mostly visited with those next doors or across the street.

            Taking this social need—that people like to socialize with those around them and do so in a roughly circular form— Alexander proposes a “spatial” cluster as the fundamental unit of neighborhood organization. Instead of the grid of tract housing that makes neighborly connection anonymous, the more social-supporting cluster form would bring back real neighborhood life.²

                In “The Grassroots Housing Process” (1973), the cluster has an activating dimension. Alexander describes a common land shared by  the residents who have a “right and obligation, to one another.” Unlike the 1950s passive style of grouped homes around a shared access, these cluster households “... build whatever they want: paths, fences...workshops, playgrounds....” or “a common pool or vegetable garden." ³ A year later in an alternative master plan proposal, People Rebuilding Berkeley,⁴ a bottom-up grassroots process of transforming the city of Berkeley is laid out over time, a reverse of centralized master plans overseen by the planning department. A Berkeley “House Clusters and Common Land” map shows after ten years “the transformation of the grid system” into one of small neighborhood clusters. Through the incremental efforts of small groups over time, the city could be made comfortable, beautiful, and whole.⁵ In Mexicali, Mexico, 1975-1976, a low- income housing project model with five interconnected clusters, generating a cluster neighborhood, was to be realized one cluster at a time. Alexander’s work exemplifies a transformative approach, one lived out day by day, and that can be seen in other housing experiments of the mid-1960s and ‘70s that emphasize shared ownership and decision-making, a more natural growth over time.

            A proliferation of yurts and domes, counterculture do-it-yourself structures, and communities harkened back to the iconic village cluster as a more authentic, and sustainable, vernacular form of living. The rough, the handmade, and the irregular—products of the human hand and heart, or nature—were the touchstones, a rejection of a pervasive machined aesthetic. Building alternative systems was not seen as utopian or experimental, but a “path,” as a commune member expressed it, “from things as they are to things as they should be.”⁶Themselves” New York Times, Dec. 17, 1970. One towards people’s own “fundamental nature.”⁷

            While many in the counterculture rejected the existing market economy, others found more success in working alongside it. Model cooperatives were established, often after long efforts to obtain approval and funding.⁸ Poorly paid farmworkers, in inadequate farm labor camp housing, formed limited-equity cooperatives to purchase and rebuild homes using their own labor.⁹ The first built cohousing project, a classic cluster layout of houses and a common house around a jointly shared outdoor space, opened in Denmark in 1972.¹⁰ That same cluster design can be seen in the first US cohousing development, Muir Commons, opened several decades later in California.

            Today, why haven’t many grid-turned- into-cluster neighborhoods materialized with more collaborative neighboring? Why are there fewer housing alternatives that emphasize social interaction and that strengthen community cohesion? Fragments of the ’70s experiments in more engaged and socially oriented housing emerge occasionally in new developments and there is clearly a link to today’s intentional communities: cohousing, eco-villages, and new models of cooperative living. But their spread in the US remains limited.

            The cluster is relationally complex in comparison to hierarchical and grid forms. Not many communes survived into the 1980s, often due to lack of communication and conflict resolution skills. Today, cooperatives are a “time tested but under-utilized tool,”¹¹ still with little support and resources for their creation. In the one Mexicali cluster that was built, families turned away from the shared courtyard and divided up the common space.¹² The cluster zeitgeist, households energized in collaborative space to create better, more humane day-to-day lives, resurfaces periodically. Here we are in the twenty-first century, once again with our (many, very human) social needs, eyeing with expectation this promising physical form. We can build it spatially, but do not necessarily provide tools for designing and sustaining its intricate social form. Cluster projects like the Mexicali Experiment remind us that the social frontier in architecture remains an unsettled space.