Self-Destruction of Diversity

Definition

The self-destruction of diversity is Jane Jacobs's fourth-party theory of urban decline: success, not failure, destroys districts. "A diversified mixture of uses at some place in the city becomes outstandingly popular and successful as a whole. Because of the location's success… ardent competition for space in this locality develops… The winners in the competition for space will represent only a narrow segment of the many uses that together created success. Whichever one or few uses have emerged as the most profitable in the locality will be repeated and repeated, crowding out and overwhelming less profitable forms of use… A most intricate and successful organism of economic mutual support and social mutual support has been destroyed by the process" (Jacobs 1961, p. 242). Her figure is the family who "picnicked on a knoll… when they finally built they put the house on the knoll. But then the knoll was gone. Somehow they had not realized they would destroy it and lose it by supplanting it with themselves" (p. 245).

The process moves downtowns ("These clumps of excessive duplication are the cause of the center's movement," p. 246), strands has-been districts, and — in residential form — is the mechanism later literatures call gentrification: "so many people want to live in the locality that it becomes profitable to build, in excessive and devastating quantity, for those who can pay the most… Accommodations for this narrow, profitable segment of population multiply, at the expense of all other tissue and all other population. Families are crowded out… This process is now occurring, very rapidly, in much of Greenwich Village, Yorkville and the midtown East Side of Manhattan" (p. 246). Banks, insurance companies and prestige offices are "consistently the most voracious double-destroyers," investing "where success is already a well-established fact" (p. 249). The diagnosis is systemic: cities "left out feedback" — the successful district behaves like Dr. Potter's "idiot" cell, continuing to produce what it no longer needs (pp. 251–252).

The remedies are "imperfect substitutes" for feedback: zoning for diversity (constraints on bulk, height and replacement speed, with tax adjustments), staunchness of public buildings (public bodies standing "staunch, no matter how valuable the property becomes"), and competitive diversion — increasing the supply of lively districts so demand stops concentrating destructively (pp. 251–253).

Key Thinkers

• Jane Jacobs — the concept's author: decline as the sequel to success (1961).
• Charles Abrams (not yet paged — see log) — the owner-planner whose Eighth Street counter-policy ("deliberately search[ing] out tenants who will add something other than restaurants") supplies the staunchness model (p. 244).

Related Concepts

• gentrification — the residential register of the same mechanism, twenty years before the term: the "narrow, profitable segment" crowding out families (p. 246).
• mixed-primary-uses — what gets destroyed: the pool of time-spread users.
• aged-buildings — what gets destroyed: the low-yield tissue the winners replace.
• cataclysmic-money — the funding side of the duplication: conventional credit pouring into "the self-destruction of diversity, to the ruination of outstanding city success" (p. 308).
• neighbourhood-character — Dovey's later register of the same crowding-out: "eventually [Fitzroy] will become… cleaner and smarter and nicer and it will lose some of that character that was actually the reason we moved there."

Source Support

Sources in the wiki that discuss this concept:

• The Death and Life of Great American Cities (Jacobs 1961) — the concept's chapter (Ch. 13, pp. 241–256): the definition (pp. 242–243); Eighth Street and Charles Abrams (pp. 243–244); Third Street's tourist sorting (p. 244); the three banks at Broad & Chestnut (p. 246); Boston's color-coded downtown map — stagnation as solid swatches of single color, the "mixed" Back Bay the only live area (pp. 247–248); Madison Square (p. 247); the London parallel (pp. 248–249); the banks as double-destroyers (p. 249); the faulty-feedback cell analogy (pp. 251–252); zoning for diversity, tax adjustments, staunchness of public buildings, competitive diversion (pp. 252–253); "the demand for lively and diversified city areas is too great for the supply" (p. 253).

Source Support linking rule: All entries in this section must be wikilinks to source note pages in wiki/source-notes/ using the source-notes/ path prefix. Never link to raw files — raw files are not wiki pages.

This page requires fuller treatment — created at the Jacobs ingest; awaits the direct engagement with Neil Smith's rent-gap theory and Sharon Zukin's arts-culture displacement cycle (both flagged in the gentrification page's log).

Open Questions

• Is the self-destruction of diversity a pre-history of gentrification — the same crowding-out described before the term existed — or a distinct market mechanism? Jacobs's mechanism is competition for space among users; later theory emphasizes the rent gap between capitalized and potential ground rent. Do they describe different moments of one process?
• Her remedies are explicitly defensive ("windbreaks… which can hardly be expected to stand fast against sustained gales," p. 252). The durable remedy is supply: "the sheer supply of diversified, lively, economically viable city localities must be increased" (p. 253). Does the wiki's housing-supply register (Wentling's Missing Middle) meet Jacobs's test, or does it supply bedrooms without diversity?