What makes us act as heroes?

Dear Engaged Bystander:  So much of the bystander literature looks at why people don't act and let someone get hurt, sexually assaulted or murdered.  Our fascination is how people can stand by and let this happen.
So what is the difference between someone who reacts and makes that leap to be a hero and what makes others just sit and watch? This recent article, Inside a Hero's Head, came across my computer based upon the jet landing in the Hudson River.  I was fascinated by the fact that they were looking at what made a hero.  Here is one interesting tid-bit:
So what makes a hero respond in a heroic way? Psychologist Scott Bea said it is likely that a concept known as "heroic imagination" lies at the root of certain people's ability to react heroically in a dangerous situation.
"Certain people have actually envisioned themselves in these scenarios and thought about how to act," he said. "Pilots, I can guarantee you, have engaged in this heroic imagination probably more than ordinary citizens. I'm guessing that flight crews have gone through this heroic imagination, as well."
So talking about sexual abuse and what we have done or what we will do makes a huge difference in helping us become heroes. 
Dr. Charles Raison, a professor at Emory University adds to this point of view, "What are the things that make people completely lose it? One of the major ones is unexpected trauma," Raison said. "The 'new' is very shocking. Training ensures that these pilots have a sense that they know what to do -- they don't have to cogitate; they don't have to think about it. In a time of stress, it's good to have a memorized program."
This perspective seems to offer yet another reason to talk about real situations, describe what was done and what can be done, and think about sharing your stories.  It may be one of our more powerful tools to getting people to do something or say something.