The previous article in this series introduced the triune brain, the three components of which handle specialized life tasks. The survival brain, or brain stem, directs automatic physiological functions, such as heartbeat and breathing, and mobilizes fight/flight behaviour in times of threat. The emotional (or limbic) brain activates positive or negative emotions which motivate us for action. The logical brain is the executive in charge of verbal and nonverbal reasoning and managing emotion and behaviour. This article highlights brain research related to helping youth to replace patterns of reactive or proactive aggression.