UC Berkeley

Organized intergroup violence is almost universally modeled as a calculated act motivated by economic factors. In contrast, it is generally assumed that non-economic factors, such as an individual's emotional state, play a role in many types of interpersonal violence, such as “crimes of passion.” We ask whether non-economic factors can also explain the well-established relationship between temperature and violence in a unique context where intergroup killings by drug-trafficking organizations (DTOs) and other interpersonal homicides are separately documented. A constellation of evidence, including the limited influence of a cash transfer program as well as comparisons with both other DTO crime and suicides, indicate that economic factors only partially mitigate the relationship between temperature and violence that we estimate in Mexico. We argue that non-economic psychological and physiological factors that are affected by temperature, modeled here as a “taste for violence,” likely play an important role in causing both interpersonal and intergroup violence.