DescriptionThe current study was designed to test a reformulation of Allport's and Kramer's "vigilance hypothesis" by applying signal detection theory to social categorization. Specifically, the impact of prejudice and specific threat concerns (e.g. terrorism or illegal immigration) was investigated. Participants were asked to assume the role of either an airport security officer facing a potential terrorist attack or a border patrol officer facing possible illegal immigration. Forty photographs were presented and participants were asked to either detain or not detain the target presented. Ten of these targets were actual terrorists or illegal immigrants. Following this task, the same 40 photographs were presented and participants classified the targets as either "Arab" or "Not Arab" (in the airport security role), or "Hispanic" or "Not Hispanic" (in the border patrol security role). Measures of sensitivity and criterion were calculated and a signal detection analysis was conducted. Results did not confirm the reformulated vigilance hypothesis. Exploratory analyses revealed that political ideology would provide a better foundation for the reformulation of the vigilance hypothesis. Political conservatives set a lower criterion to categorize a target as a threat. Additionally context interacted with political ideology to impact sensitivity to threat. Specifically political conservatives displayed greater sensitivity to illegal immigrants while liberals displayed greater sensitivity to terrorists. Political conservatives also displayed greater sensitivity except when the cost of a false alarm exceeded the cost of a miss. Implications and future directions are discussed.