III. Theoretical Perspectives in Crime Mapping Research
As previously noted, the development of tools and techniques of crime mapping have been accompanied by an expanding body of criminological theory oriented toward explaining the geographic patterns of crime. It is important, when discussing theories about the spatial distribution of crime, to distinguish between theories that explain criminality and theories that explain criminal events. Traditional criminological approaches tend to emphasize individual-level social and psychological characteristics as the main factors that lead to criminality, that is, the propensity toward committing criminal acts. These theories focus predominately on explaining why offenders engage and persist in criminal lifestyles. Alternatively, theories that discuss the spatial distribution of crime focus on explaining the patterns seen in criminal events, that is, the occurrences of crime. These theories focus less attention on the motivations of offenders and more attention on factors of the environment that promote crime.
A. Social Disorganization Theory
Although a number of theories have been proposed to explain why particular neighborhoods experience high crime rates, social disorganization theory has been the most influential. Social disorganization theory, as first proposed by Shaw and McKay (1942), can be seen as the first attempt to construct a criminological theory of place. The concept of social disorganization refers to “the inability of local communities to realize the common values of their residents or solve commonly experienced problems” (Bursik, 1988, p. 521). As such, disorganized communities suffer from diminished capacities to exercise social control and are unable to regulate the behavior of community members (see Bursik & Grasmick, 1993). As the capacity of a community to regulate the behavior of its members decreases, the potential for illegal activity increases.
A central tenet of social disorganization theory is that structural conditions within a neighborhood attenuate the social ties that promote social cohesion and enable community members to exercise social control. Economic depravation creates undesirable living conditions that promote residential instability and population heterogeneity. Because social ties require time to form, high residential instability in neighborhoods prevents the development of social ties as residents frequently relocate (Bursik & Grasmick, 1993). In neighborhoods with high levels of population heterogeneity the extensiveness of friendship and acquaintance networks through which social control is exercised is limited because of social and cultural barriers between residents (Bursik & Grasmick, 1993). Structural factors such as these compromise the social integration of neighborhood residents and undermine perceptions of collective efficacy, that is, the collective sense of trust, social cohesion, and willingness to intervene on behalf of the public good (Sampson, Raudenbush, & Earls, 1997). Neighborhoods that have low collective efficacy are likely to experience high levels of crime.
B. Routine Activities Theory
Cohen and Felson’s (1979) routine activities theory has been applied extensively to research on spatial patterns of crime. To Cohen and Felson, crime is a predatory activity and, as such, can subsist only near patterns of legitimate activity. Therefore, to understand crime patterns it is necessary to understand the patterns of conventional routine activities around which crime is organized. Criminal victimization occurs where routine activities produce a convergence in space and time of the three necessary conditions for crime to occur: (1) a suitable target, (2) a motivated offender, and (3) the absence of capable guardians (Cohen & Felson, 1979). Felson (1998) explained that suitable targets have value to the offender, are visible to the offender, are easily moved or removed, and are accessible by the offender. The concept of guardianship has also been extended and includes intimate handlers, who are responsible for monitoring the behavior of offenders; guardians, who are responsible for protecting targets; and place managers, who are responsible for monitoring and controlling access to particular spaces (see Eck, 2001). In applications of this theory to spatial crime analysis, structural features of the city, patterns of land use, and the routine activities associated with particular locations can concentrate motivated offenders and suitable targets into areas with limited guardianship. This, in turn, fosters opportunities for criminal victimization.
C. Crime Prevention Through Environmental Design and Defensible Space Theories
A couple of important theories have been proposed to explain why criminal events occur more frequently at particular sites. Jeffery (1971) was one of the first criminologists to suggest that immediate features of the environment affected crime, with his Crime Prevention Through Environmental Design (CPTED) approach. This approach emphasizes target hardening and surveillance. Contemporaneously, Newman (1972) also emphasized the role of the environment in creating crime with his defensible space theory. Newman argued, in regard to public housing, that it is possible to design the use of space to enhance territorial functioning and to improve the natural surveillance in these environments. Crowe (2000) expanded on both Jefferey’s and Newman’s initial theories. In the current formulation of CPTED, Crowe discussed three strategies that are used to prevent crime: (1) access control to prevent contact between the offender and the target, (2) surveillance to monitor areas and discourage offenders, and (3) territorial reinforcement to promote feelings of ownership among users of the space. CPTED is usually employed along with situational crime prevention (discussed in the next section) to formulate practical strategies for reducing crime.
D. Rational Choice Perspective and Situational Crime Prevention
The rational choice perspective (Cornish & Clarke, 1986) is primarily concerned with understanding offender decision making. This approach assumes that offenders possess limited rationality, meaning that they make rational calculations of the costs and benefits associated with crime but are constrained in their decision making by time, information, context, ability, and prior experiences. This perspective seeks to understand the series of decisions made by the offender that result in a criminal event. Interestingly, unlike many other theories of offending, the rational choice perspective emphasizes that different decisions are involved in the production of different types of crime. Rational choice explanations of criminal offending differ by crime type, instead of ignoring these differences in favor of a general motivation toward engaging in crime, as is common in many other criminological theories. Spatial applications of the rational choice perspective emphasize offender movement, search patterns, and target selection processes that determine the spatial patterns observed in crime.
Situational crime prevention (Clarke, 1997) refers to the application of the rational choice perspective toward developing policy recommendations to reduce crime. Situational crime prevention emphasizes situational-level interventions toward increasing the efforts associated with committing a crime, increasing the perceived risks for engaging in crime, reducing the anticipated rewards from crime, and removing the excuses associated with crime (Clarke, 1997). As with the CPTED and defensible space theories, the policy applications of situational crime prevention focus on practical strategies that are customized to specific settings. Although the successes of this approach are well documented, rarely do the methods used in these studies permit broad conclusions regarding the effectiveness of this approach at reducing crime (see Clarke, 1997, for a discussion).
E. Crime Pattern Theory
Brantingham and Brantingham (1991b, 1993) developed a perspective referred to as crime pattern theory that incorporates elements of the rational choice, routine activities, and other spatial perspectives on crime. According to this perspective, individuals create a cognitive map of their spatial environment with which they are familiar through their routine activities. The action space of an individual consists of (a) nodes, the destinations of travel, such as work, home, and entertainment locations, and (b) paths, the travel routes that individuals take to move from one node to another. Through repeated movement along paths to various nodes, individuals develop an awareness space consisting of the areas in a city with which they are familiar. According to this theory, offenders search for suitable targets primarily within this awareness space by comparing potential targets against templates, or mental conceptualizations of the characteristics of appropriate targets. The likelihood of a particular target being selected by an offender dramatically decreases as an offender moves away from his or her awareness space, a process often referred to as distance decay (see Rengert, Piquero, & Jones, 1999). One interesting application of this theory is geographic profiling, which attempts to narrow the scope of police investigations by using information on repeated crimes to identify the awareness space of a repeat criminal (Rossmo, 2000).