The need for cognitive closure is a function of an individual's desire for predictability, preference for order and structure, discomfort with ambiguity, decisiveness, and level of close-mindedness. Extremist ideology is often appealing to individuals under high need for closure because such ideologies paint a black-and-white picture of the world. A research team led by Arie Kruglanski traced the relation between psychological uncertainty, need for closure, and support for extreme ideologies, as well as for terrorism, in an effort to further identify characteristics of individuals who may be more vulnerable to efforts at terrorist recruitment.
Terrorist ideologues have articulated arguments for the efficacy of terrorism as a tactic of psychological warfare. The most basic tenet of their argument has been that a terrorist attack impacts the targeted society by creating a state of instability. As the ideologues of terrorism intuited correctly, our data imply that acts of terrorism instill in individuals an elevated need for cognitive closure (Studies 1 and 2). Data collected for this project suggest that, rather than undermining support for government, need for closure arousal enhanced the feelings of solidarity among group members (Studies 2 and 3), often manifesting itself in bias against outgroups (Studies 2, 3, and 4), and support for tough counterterrorism tactics (Studies 3 and 4). As Study 4 further found, support for tough counterterrorism may account for the relation between need for closure and optimism about future safety from terrorism. Specifically, results suggest that while the need for closure may prompt a "rally effect" and support for the leadership of one's group, these tendencies may be qualified by the perceived potential of the leadership to restore certainty and closure. In this vein, Study 5 results suggest that though need for closure is positively related to support for a decisive leader, it is negatively related to support for an indecisive one. Put simply, need for closure is positively related to support for individuals or activities that seem likely to provide closure and is negatively related to support for individuals and activities that seem likely to undermine closure. It is possible then, that acts of terrorism and the resulting elevation in the need for closure could lead to a destabilization of the state in conditions in which the leader is perceived to be less decisive.
In Study 1, the research team manipulated whether or not participants were reminded of the attacks on 9/11, and found that such reminders influenced responses on the need for closure scale. In Study 2, researchers assessed the percentage of Muslims in the participants' neighborhood, their need for closure, and their in-group favoritism. These measures were correlated such that the percentage of Muslims in participants' neighborhood predicted their need for closure, and their need for closure predicted their in-group favoritism. Studies 3 and 4 included measures of need for closure and support for counterterrorism policies. In both studies, a significant correlation between these measures was obtained. In Study 5, participants high on the need for closure preferred a description of an open-minded leader, which participants low on the need for closure preferred a description of a decisive leader.