On a cold night in March 1964, piercing screams woke a neighborhood in Queens, N.Y., and stunned the nation. Forty-five years later, the authors of "SuperFreakonomics," Steven Levitt and Stephen Dubner, reconsidered those cries for help and asked themselves, "Do we only care about ourselves?"
Twenty-eight-year-old Kitty Genovese was walking toward her apartment unaware that a stranger, Winston Moseley, was following her. He then took a knife out of his pocket and ran toward her.
"He stabbed her in the back two to four times with a hunting knife," Queens historian Joe De May said. "Kitty Genovese screamed bloody murder."
Lights went on in the apartment building across the street. Someone yelled out the window to leave her alone. Startled, the attacker ran back to his car and waited. Genovese summoned the strength to pick herself up and walked around to the back of the building, but she couldn't make it to her own apartment. Moseley found her, collapsed inside the vestibule to another apartment. He stabbed her again and left her to die.
Watch this story on "20/20" TONIGHT at 10 p.m. ET
The crime would soon become infamous -- not simply because of the horrifying things done to Genovese -- but because of what her neighbors didn't do.
"For more than half an hour, 38 respectable, law-abiding citizens in Queens watched a killer stalk and stab a woman in three separate attacks," the New York Times reported. "Not one person telephoned the police during the assault."
The idea that no one would call for help -- no one from that apartment building would call police -- shocked an entire nation. It was the mid-60s, crime was on the rise, President Kennedy had been assassinated and people were asking: Do we not care about anyone but ourselves?
"The Kitty Genovese crime, the murder, became a symbol of all that was going wrong with the world," Dubner said. "Of how incredibly, cruelly selfish human beings can be."
The crime got social scientists wondering if we would ignore our own neighbors in need, how about those closest to us?
Honor Thy Mother and Father?
What the "SuperFreakonomics" duo found at retirement homes surprised them.
"If you're a parent in a nursing home, the best predictor that your child will show up is if you, the parent, are quite rich," Levitt said. "Children of rich parents are much more likely to show up in nursing homes than are children of poor parents."
But even that wasn't a guarantee.
"If you didn't have to compete against your brothers and sisters to go and get the bequest, you didn't show up at the nursing home," said Levitt.
It may sound depressing to think that's what drives us, but as Dubner said, "It would be depressing if we were all just cruel and selfish all the time, but we know we're not."
Americans donate $300 billion to charity every year, according to Giving USA 2009. Clearly, we are incredibly giving. So what gives? Is this pure altruism or does something else motivate us to give?
Good-Looking People Raise More Money
Economist John List of the University of Chicago has spent years developing creative experiments that shed light on what motivates people to be altruistic. In one experiment, he looked into what effect the appearance of a solicitor has on donations for charity.
List starts by taking pictures of his solicitors and has them graded on a scale from one to 10 by independent evaluators before sending them door to door to solicit money for charity.
Turns out, the best-looking people raised more money.
"When you go from the average physical attraction from a five to a seven that will cause twice as many households to give," List said.
Economists point out that the amount we give almost always has some sort of strings attached.
Colleges and universities promise donors they'll etch names onto buildings. And in doing so, the colleges get their donations. Charities throw big parties, where high society donors can see and be seen. And the charities win, too. And the local church figured that out long ago. There's a reason why that basket passed around is open. Everyone can see what everyone else is giving.
Scrutiny: Key to Generosity?
So, are we more altruistic when we know someone is watching us?
"Yes. Scrutiny," Dubner said. "If you want to make people be generous, scrutinize them."
But there have to be some people who are truly altruistic. How do you explain the New York subway hero, who jumped onto the tracks to save a young man who'd fallen into the path of an oncoming train? Dozens of others stood by and watched.
"There are those saintly few who seem to be altruistic all the times under every circumstance at whatever the cost to themselves," Dubner said. "Think of whoever your mind conjures -- Mother Teresa, some people might say. The reason your mind can conjure those people are because there are so few of them. If there were a whole lot, they wouldn't come to mind so easily."
So, if there really are a saintly few who are purely altruistic, where do the rest of us fall?
'People Are People'
Levitt and Dubner say most of us fall somewhere in between. It just depends on what's in it for us.
"We found out that people aren't as bad as you think they are, but they're probably not as good as you think they are, either. People are people," Dubner said.
Forty-five years later and back to that night Kitty Genovese was murdered: Were all of those people really as apathetic, as uncaring as they seemed? Turns out, what we've thought for 45 years about those apathetic neighbors was wrong.
"Most people imagine the crime as 38 people sitting by their windows or standing by their windows watching for half an hour while a woman is brutally murdered," De May pointed out. "That didn't happen."
De May says only a few neighbors actually saw anything. Most woke up confused. It was a cold night, so the windows were closed. Some only made it to their windows after Genovese got up. Others thought they were hearing noise from a rowdy bar.
But, had the story been reported accurately all those years ago, would we still be talking about it today?
"It might have been a four-day story. It might have been a four-week story. It would not have been a 45-year story," De May said.
And just how was Genovese's killer finally arrested? It was just a few days after the murder. Moseley was seen stealing a television set out of someone's home.
One neighbor ran to call the police while another removed the distributor cap on Moseley's car, disabling it and keeping him from getting away.
Minutes later, the killer was under arrest. And in the end, all because of neighbors who saw something...and helped.