應用最佳覓食理論分析連續竊盜犯的空間移動型態

Abstract

In the last decades, a novel theory was introduced to the geography of crime, called optimal foraging theory. This theory explains repeat victimization and 'near repeat' victimization well, which are major concerns in the geography of crime. It assumes that the moving behavior of serial offenders is composed of two types of movement: foraging and searching. However, to date the moving behavior of serial offenders has not been well investigated. Therefore, this study was aimed at identifying the frequency and the spatial scale of these two different inter-crime movements. We designed a grid-based transition probability matrix to record the moving behavior of 31 serial burglars in Taipei Metropolis. For further analysis and comparison, an index was created to represent moving characteristics ─ the Behavior Index. In order to understand the moving behavior thoroughly, we conducted simulations with different moving behaviors and found the corresponding moving behavior of real burglars. This study found that there was an 80% chance that a serial burglar in Taipei would commit a subsequent offence within a 2.4-km radius of the former event, which indicates a general pattern of more searching. However, as we adjusted the definition of foraging, the frequency between foraging and searching also changed. The frequency depended to some extent on the definition of the spatial scale. This study also found that the Behavior Index is correlated with the commuting characteristic on Journey to Crime of burglars. When the commuting characteristic of burglars is stronger, the corresponded Behavior Index was significantly lower. This study can improve the current knowledge about the moving behavior of serial offenders and can inform strategies for preventing and predicting crimes.