"The longest debate since humans have been having debates is whether we are good or evil. It underlies the stories of Adam and Eve, Cain and Abel, Jesus and Judas.
What is our human nature? Of course, the answer is we can be both good and evil. But what determines which part of our character emerges?
About a decade ago, my lab made an unexpected breakthrough in the understanding of good and evil. We discovered that the neurochemical oxytocin makes people trustworthy. We then found oxytocin was responsible for many other moral behaviors, from being generous to sacrificing to help a stranger."