Mindfulness induction and aggressive behaviour

The first aim of the current study is to examine whether reductions in aggressive

behaviour could occur by experimentally manipulating individuals’ levels of

mindfulness, using a 10-min of mindful walking exercise (Kabat-Zinn, 1994; Sujiva, 2000). Given that mindfulness is generally studied as a dispositional form and as a result of therapeutic interventions, most aggression literature has also explored the role of mindfulness in these contexts. As previously discussed, trait mindfulness was shown to be related to various self-reported measures of aggression (e.g., Barnes et al., 2007; Borders et al., 2010; Brown & Ryan, 2003; Kelly & Lambert, 2012). Our results from Study 1 also found negative relationship between trait mindfulness and trait aggression, physical and verbal aggression, anger, and hostility. In mental health

and forensic settings, several authors have recommended the potential applications for mindfulness-based treatment of aggression and anger (see Howells, 2010; Howells et al., 2010; Wright et al., 2009; also Singh and colleagues series of case studies, 2003, 2007, 2011).

More recently, the benefit of mindfulness on emotion-related processes is proposed to be observed through brief laboratory inductions, using a short guided meditation instruction to adopt an accepting attitude toward one’s experiences (for a review, see Keng et al., 2011). In this context, however, only one reported aggression study (Heppner et al., 2008) actively manipulated participants’ state of mindfulness (using a raisin eating task), providing a preliminary support for the potential effect of state mindfulness on aggressive behaviour (a description of this study is provided in section 1.2.2.4, Chapter 1). As in Heppner et al.’s study, our current study employs the same measure of aggressive behaviour called the Taylor Competitive Reaction Time (TCRT: Taylor, 1967) task, specifically in its adapted form.

In typical work using the TCRT task, participants play a computer-based competitive reaction-time task against a bogus partner, where the winner of each trial is given opportunity to deliver a noise blast/electric shock to the loser. In the adapted version of the TCRT task, a non-aggressive option is provided for the participants (e.g., De Wall, Buckner, Lambert, Cohen, & Fincham, 2010; Konrath, Bushman & Campbell, 2006; Muller, Bushman, Subra, & Ceaux, 2012; for critics on the importance of providing non-aggressive response options, see Ritter & Eslea, 2005; Tedeschi & Quigley, 1996). Following past research (Anderson, Buckley, & Carnagey, 2008; Lawrence & Hutchinson, 2013a, 2013b), we use participant’s intensity of the

noise blasts to the bogus opponent as a main measure of direct aggression.

Bettencourt, Talley, Benjamin, and Valentine’s (2006) meta-analytic review concludes that the influence of personality variables on aggressive behaviour may differ under provoking and nonprovoking conditions. This indicates the necessity for the current study to distinguish the proposed effect of mindfulness induction on provoked and unprovoked aggression, and account for the potential role of individual differences (trait mindfulness, self-control, aggression, self-harm, SP, and

SF). While higher blast intensities are commonly associated with increased levels of provocation, interventions aimed at reducing aggression in the TCRT task tend to lose their effectiveness under high provocations (see Lawrence & Hutchinson, 2013a, 2013b). Thus instead of using a social rejection task in Hepper et al.’s (2008) study to provoke aggression, we vary the levels of provocation in the TCRT task, such that participants are exposed to no provocation, low provocation, and high provocation trials. By doing so, it is possible to see whether any impact of mindfulness induction would persist despite opponents’ increases in levels of provocation.

As concluded by Giancola and Parrot (2008), it is more likely for people to engage in implicit aggression (represented by shock duration in the TCRT task) than explicit aggressions (shock intensity) when their aggressive impulses are inhibited by other factors, such as cultural values and sex role norms. In the current study, we include measure of the maximum latency (the delay duration before the maximum blast was delivered the opponent in the TCRT task; see Lawrence & Hutchinson, 2013a, 2013b), which is arguably similar to shock duration in its more subtle form of aggression. In this way, the potential influence of mindfulness induction on different types of aggression can be explored.

We also assess aggressive behaviour in terms of indirect aggression, specifically through participants’ anonymous reputation damage of the opponent. A negative judgment would reflect an immediate intent to cause harm to the target, which corresponds to Bushman and Anderson’s (2001) widely accepted definition of aggression. A similar method has been used as a sole measure of aggressive behaviour in many previous studies (e.g., De Wall et al., 2007; Stucke & Baumeister, 2006; Twenge, Baumeister, Tice, & Stucke, 2001). While higher levels of direct aggression in the TCRT task have been demonstrated in males than in females (Giancola & Parrott, 2008), sex differences in aggression typically narrows when indirect aggression is measured (see Card, Stucky, Sawalani, & Little, 2008).

In addition, the current study examines the proposed effect of mindfulness induction on a behavioural measure of self-control performance as an additional dependent variable beyond aggressive behaviour. Specifically, we use performance in a

handgrip task that has been identified as one of the frequently used dependent task in Hagger’s et al. (2010) meta-analysis. We expect that the immediate effect of mindfulness induction on self-control performance would be sustained after participants have engaged in a provocation procedure.