Martijn van Teffelen

General introduction 13 1 shocks (Taylor, 1967), aversive noise blasts (Bushman, 1995) and social exclusion (Twenge et al., 2001). However, knowledge is still limited on potential differences between diverse provocation techniques in eliciting aggression and other outcome measures, as different provocation techniques have not been directly compared to each other. Moreover, empirical evidence suggests that (among others) two specific personality traits might differentially impact the provocation-aggression relationship: psychopathy and narcissism. On the one hand, psychopathy is characterized by affective deficiency. Studies generally find two psychopathy factors (Harpur et al., 1989); one factor representing a personality dimension (i.e., egocentricity, lack of empathy, lack of guilt and impaired affective processing), and the other factor representing a behavioral dimension (i.e., unstable, and antisocial lifestyle or social deviance). Findings on the psychopathy-provoked aggression relationship indicate that affective deficits in people with psychopathic traits may ‘dampen’, or negatively mediate the provocation-aggression relationship (Reidy et al., 2011). On the other hand, narcissistic people tend to harbor a cognitive-affective preoccupation with the self, including grandiose self-expectations, superiority, and entitlement (Emmons, 1987; Raskin & Hall, 1979). Findings on the narcissism-provoked aggression relationship indicate that narcissistic traits attenuate, or positively mediate the provocation-aggression relationship. EXTINGUISHING THE FLAME: REDUCING HOSTILITY To reduce hostility, clinicians have several psychological interventions at their disposal. In the literature, most of these interventions are offered as part of some larger cognitive behavioral therapy (CBT) package. CBT interventions that have shown to successfully reduce hostility include psychoeducation, behavioral skills training, relaxation exercises, exposure, and cognitive restructuring (CR) (DiGuiseppe & Tafrate, 2003). A meta-analytic review of meta- analyses revealed that CBT programs for hostility show a response rate of 66%. This indicates that 66% of people receiving CBT report a symptom reduction of 50% or more (Hofmann et al., 2012). However, treatment effects appear less pronounced compared to those of other psychopathologies (e.g., depression, panic disorder, body dysmorphic disorder) and treatment discontinuation is significant (Arntz et al., 2015; Cassiello-Robbins et al., 2015; Putt et al., 2001). Moreover, patients with increased levels of hostility are often described by therapists as ‘challenging’ (von der Lippe et al., 2008), and a significant number of patients (34%) do not profit from treatment (Hofmann et al., 2012). Furthermore, few high-quality treatment effects studies on hostility have been conducted (Del Vecchio & O’Leary, 2004). This leaves room for improvement.