From
http://www.thisamericanlife.org/radio-archives/episode/521/transcript

Act Two. The Road To Badness.

Ira Glass
So when does somebody turn bad? When does it happen? Can you truly be said to be bad when you're, you know, 10 or six or-- OK, here the answer's going to get more obvious-- when you're two or six months old?

Paul Bloom
Well, I don't think a baby can be bad in a sense of being malevolent, getting delight from the pain and suffering of others. We just don't see that.

Ira Glass
Paul Bloom is a professor at Yale who does experiments with babies to try to understand their sense of right and wrong, good and bad. He wrote a book about it.

Paul Bloom
It's not that there's a desire to cause pain and suffering. It's not like what he said about the Joker in The Dark Knight, that some people just want the world to burn. You don't see that in babies. But what you see is selfish desires.

Ira Glass
They want food. They want attention. They want comfort. And they do not care what anybody else wants. Also, research shows they're nicer to people they know. They don't give a damn about strangers. And they're racist. Babies are racist. OK, not exactly racist. But they prefer whatever race of people they are used to seeing and being around. If they're raised in a multiracial setting, they're fine with all the different races that they're used to.

Ira Glass
Thinking about this as much as you do, when do you think people turn bad?

Paul Bloom
I don't really think of that as the right question. I think that to a large extent, we start off bad. We start off with these powerful selfish impulses. And what happens mostly through acculturation and development is we become good. We become more generous.

And a lot of the evil in the world is caused by people who, for whatever reason, missed out on us. They missed out on getting their morality expanded to care about other races. They missed out on the capacity to exercise their self-control.

So to some extent, and this is an exaggeration, but to some extent, the most evil adult in the world is a two-year-old who never grew up, is a two-year-old who never managed to get control over his impulses. There's some studies that suggest that the peak of human violence is at age two. We are most violent of all at that age.

Ira Glass
There's a really nice passage in your book where you write, quote, "Families survive the terrible twos because toddlers aren't strong enough to kill with their hands and aren't capable of using lethal weapons."

Paul Bloom
Having had two-year-olds, I truly believe that.

Ira Glass
Paul Bloom. His book about all this is called Just Babies-- The Origins of Good and Evil.