Life and death in Upper Manhattan and the Bronx: toward an evolutionary perspective on catastrophic social change

During the 1970s, poor neighborhoods of New York City lost significant proportions of housing and associated community structure to a policy-driven process of contagious fire and building abandonment. The south Bronx was among the most heavily damaged areas. Here we analyze and compare the interrelationships between socioeconomic factors, housing, demographics, and two health outcomes (low-weight birth rate and homicide rate) in the southwest Bronx and in Upper Manhattan (Harlem, Washington Heights, Inwood), using standard statistical methods as well as the Ives amplification factor employed by ecologists. Upper Manhattan showed much stronger and less 'resilient' relationships between these factors than the southwest Bronx, that is, a system of tight ties which amplifies external perturbations. It indicates vulnerability to impacts such as economic decline, changes in municipal service provision, and 'welfare reform'. We hypothesize that the looser, and more resilient, system of the southwest Bronx and the brittle system of Upper Manhattan arose from their different histories of catastrophic urban decay, a highly 'path dependent' evolutionary process affecting a social system, subjecting it to extreme selection pressures on the underlying social network structure. The difference has profound policy implications.