In her 1961 classic, The Death and Life of Great American Cities, Jane Jacobs opposed what she called "one size fits all" planning. This idea of letting a mixture of land uses and housing styles evolve over time set her in contrast with the approaches of Ebenezer Howard, Le Corbusier, and Robert Moses, who preferred to redevelop large swaths of the city at once. On the contrary, wrote Jacobs, healthy neighborhoods must "mingle buildings that vary in age and condition, including a good proportion of old ones."
Simply put, Jacobs felt one-size-fits-all planners often failed to recognize that "healthy cities are organic, spontaneous, messy, complex systems," writes Duke sociologist Katherine King in an upcoming issue of the journal Urban Studies. This preference for gradual (as opposed to grand) redevelopment carries a number of possible social implications — a chief one being that it should promote stronger community relationships.
Recently King put Jacobs's belief to an empirical test. A few studies of housing type and social relations have been done over the years: researchers have found that residents of townhouses or villas have higher social capital than those in apartments or flats; that even the position of doors and common spaces can influence social contact; and that older housing does seem to promote interaction. However the idea that gradual redevelopment improves social ties hasn't really been studied in a direct sense.
"It remains to be seen whether the diversity of forms created by gradual development in fact predicts better neighbourly social relations," writes King. (A note to typo-conscious American readers: the journal is published in the United Kingdom.)
To address this gap in the literature, King studied surveys of Chicago neighborhoods that included measures of community relations. She established four metrics of social ties: cohesion (shared values), control (a belief that community works toward a collective good), inter-generational closure (adults looking after local youth), and reciprocal exchange (trading favors, advice, information, etc.). Then she matched this information with data on the "age diversity" of housing — a proxy for gradual redevelopment, since a mixture of building ages might represent neighborhood evolution.
The results showed quite clearly that a mixture of buildings indicated strong social ties. Mid-century housing age was significantly associated with all four types of social relations, while recent construction had a negative association with social control in particular. Once King controlled for other demographic factors, only housing "age diversity" kept its significant link with all four social metrics she measured.
Empirical results show significant links between housing age diversity (historical development pace) and four measures of neighbourly social relations, even when controlling for other neighbourhood housing features, social composition and individual sociodemographics. It may be that gradual redevelopment preserves community ties, which may take decades to form and which new residents may 'inherit' from previous neighbours.
Now the findings represent a correlation, as opposed to a cause, and there are some other possible explanations for it. Perhaps there's some other quality about neighborhoods that have resisted massive redevelopment that give rise to social interaction — or perhaps the interactions themselves have prevented the major changes. Elements of transport, commercial opportunities, or established public institutions might have played a role.
But at the very least, the results should get planners to stop and wonder whether newer is always better.
Image via King, K. (2013). Jane Jacobs and 'The Need for Aged Buildings': Neighbourhood Historical Development Pace and Community Social Relations. Urban Studies. DOI: 10.1177/0042098013477698.