The brain develops the connections according to what it experiences in those formative early years - those experiences are in the context of relationships. If your environment is one of violence and aggression, most likely the 'fight or flight' response will be overly developed. You will be more likely to over-react to situations of stress, and use aggression or violence.
So, now, in this summer of our discontent made potentially riotous by our sons and daughters of Tottenham, it matters enough to me that I write these black words on this white page to express a rage measuredly and peacefully. Because it really does matter to me. Every day. My Black Life matters to me. I often doubt, Dear Reader, that it matters to you.