Buttress self esteem - reduce aggression

Here is a fascinating study from Thomaes et al. They conducted a randomized field trial in the Netherlands to assess the efficacy of a brief affirmation exercise designed to buttress self-esteem. Before the intervention, aggressive behavior was prevalent among the individuals who scored high on the narcissism scale and low on self-esteem. Afterward, acts of aggression decreased even though the individual levels of self-esteem (both high and low) were unchanged. Here is the abstract:

Narcissistic individuals are prone to become aggressive when their egos are threatened. We report a randomized field experiment that tested whether a social-psychological intervention designed to lessen the impact of ego threat reduces narcissistic aggression. A sample of 405 young adolescents (mean age = 13.9 years) were randomly assigned to complete either a short self-affirmation writing assignment (which allowed them to reflect on their personally important values) or a control writing assignment. We expected that the self-affirmation would temporarily attenuate the ego-protective motivations that normally drive narcissists' aggression. As expected, the self-affirmation writing assignment reduced narcissistic aggression for a period of a school week, that is, for a period up to 400 times the duration of the intervention itself. These results provide the first empirical demonstration that buttressing self-esteem (as opposed to boosting self-esteem) can be effective at reducing aggression in at-risk youth.