if you know some of the risk factors you describe in the book, is there something that can be done at that point to say, look, we know -- we have identified high risk people because we have objective evidence that this caused changes in the brain. what can we do as individuals or as a society? >> we can certainly do something to change things. in fact, one of the reasons for writing the anatomy of violence is i wanted to open up a new door to everyone. a new way of looking at violence and the causes of crime and violence. and the brain can change for the better with a better environment. so, for example, we enrich the environment of 3-year-old children by giving them better nutrition, more physical exercise and a cognitive stimulation for two years from age 3 to 5. that resulted in better brain functioning at age 11 and a 35% reduction in criminal offending at age 23. so it's not biology by itself.