heart rate is really one of the best replicated of behavior. >> in part of these studies you took somebody and put them in a condition that had a loud noise or something and tried to figure out, do their hearts rate go up and, that was a flag? >> we put 800 children into the experiment where we mentioned fear conditioning. they have fear before a punishment comes on. and what we found is that the 3 year olds who really showed a lack of fear at that time, they were more likely to go on to become criminal offenders 20 years later. >> again, as a neuro scientist, if you know some of these risk factors now, which you describe in the book, is there something that can be done then at that point to say, look, we know we've identified the high-risk people because we have objective evidence that this has caused