In addition to his concentric zone theory, Ernest W. Burgess provided sociology with a rationalization of the city expansion process, how to measure it and its effect on social systems. His two major questions, what is a normal rate of expansion in a city at which pace social organization remains in tact; and what movement is occurring and how can we measure it.
Burgess’ explanation of the expansion process is best described using his concentric zone model through which a city expands outwardly beginning in the central business district. He names each zone I-V and describes each as follows:
Zone I-central business district-occupied by shopping and commerce and homeless.
Zone III-working class zone-where the zone II workers reside
Zone IV-residential zone-middle/upper middle class residences
Zone V-commuters zone/suburbs
The expansion into another zone is what Burgess termed succession, or the “tendency of each inner zone to extend its area by the invasion of the next outer zone”. Burgess describes this succession as a continual expansion process, whereby groups in each zone continue to expand concentrically outward until they reach the suburbs. Groups tend to move outwardly with culturally, professionally and economically similar individuals, creating a homogenous area.
Burgess makes a distinction between movement and mobility. Movement does not always indicate mobility; mobility is defined here as a “change of movement in response to a new stimuli”. New stimuli cause individuals to respond. The individual can respond in one of two ways, integral or segmental; the former being a wholesome reaction and the latter is pathological response. These pathological responses give rise to social disorganization and deterioration.
Upon further description of these zones, Burgess finds that zone II, inhabited primarily by immigrants, is an area of deterioration where slums and poverty and “underworlds of crime and vice” have taken hold. It is in this zone that effects of mobility can be clearly seen. The primary reason for this is a rapid influx of immigrants in zone II, causing current residents to expand into zone III, and zone III residents to move outward to zone IV, and so on. Rapid expansion can create disequilibrium in individuals as well as within the social system. As echoed by his partner, Robert Ezra Park, rapid “invasion”, can create disequilibrium in the social system leading to social disorganization. Individuals also experience conflict when reorganized into a new class, culture, or recreational group. Burgess says maybe because we can’t adjust to having two sets of conduct expectations, the old and the new.