Small Children and Crime

I have wondered if the children chosen to star in movies and TV programs are effected by the made up violence around them. I would love a pole of children stars who witnessed made up arguments and violence, to see if they were effected in thier later years. A baby wouldnt know the difference in a real argument, in a real murder. Real life situations do indeed , determine how a child develops, and learns. Why wouldnt the made up situations do the samr. Just wondering here.