- When today's most popular social media platforms were invented, tech companies said they would create a sense of community and bring people closer.

But it didn't take long for the dark side of human nature to show up online, from bullying and shaming to explicit violence.

- And with all of this streaming live on our phones, there's growing alarm about people just watching, becoming bystanders instead of intervening or calling the police.

But it turns out our tendency to just stand by isn't unique to the digital age.

It was revealed decades ago after an infamous New York City murder case long before social media ever entered the picture.

(upbeat music) - My life.

- What up peeps?

- We are live from Phuket Walking Street.

- [Male Announcer] Two months after the public launch of Facebook Live in 2016, more than 800,000 people tuned in to watch an exploding watermelon.

(cheering) Yeah, described by the company as a great medium for sharing raw and visceral content, has been used to stream events from the silly to the serious.

- [Police Officer] Everybody moves down.

- [Male Announcer] But then it captured the aftermath of a fatal police shooting.

- He let the officer know that he was, he had a firearm and he was reaching for his wallet and the officer just shot him in his arm.

- [Male Announcer] And then this.

- A 15-year old girl sexually assaulted by four or five teenage boys who streamed what they did on Facebook live.

- [Male Announcer] Professor Desmond Patton studies the relationship between youth violence and social media.

We now have a window into what's happening in communities where trauma and stress and violence are everyday occurrences and so Facebook live captures those moments, inadvertently or advertently.

- [Male Announcer] In the sexual assault case, Chicago police charged two juveniles with taking part and using their phones to share it online.

- There is this thing that happens around celebrity and who's seeing this.

How far can it reach, and will it make me famous?

- [Newscaster] Authorities say at least 40 people viewed the Facebook live video but not a single person called police.

- It just disgusts me-- - [Male Announcer] But police went out of their way to chastise another group, what might be called the digital bystanders.

- Where are we going?

What are we doing as a society that people will actually look at those crimes taking place and not pick up the phone and dial 911.

- [Male Announcer] But that troubling question is not unique to the digital age.

Take a case from the 1960's in New York City, where 28-year old Catherine Genovese, or Kitty as she was called, lived with a partner, Mary Ann Zielonko.

- She was very outgoing, very gregarious, very people-oriented.

We were sort of closeted.

Just yeah, I just never thought about it.

You know it just was my life.

- [Male Announcer] They shared an apartment in Kew Gardens, Queens.

- We just both tended bar.

Lived a very quiet life.

The area was very, very nice.

It was rather artsy in a way.

Kew Gardens was really very safe.

- [Male Announcer] But late one night in March, 1964, Genovese drove home from the bar she managed, unaware she was being followed by a serial killer.

As she got out of her car she saw Winston Moseley ad started to run.

- This is where the killer must have started to catch up with Kitty Genovese.

She didn't quite make it half-way down the block before the killer drove a knife into her.

- She screams "Oh my God, he stabbed me.

Help me, somebody help me."

And she goes down on the ground, and she continues to scream.

There are lights going on in the apartment houses, windows going up and a man looked out and he yelled leave that girl alone.

- [Male Announcer] Witnesses saw Moseley, startled by the noise, run away.

But none of Genovese's neighbors came to her aid, even as she staggered into a nearby doorway, screaming again for help.

- [Female Narrator] She's lying helpless on the floor and the door opens.

It's her attacker.

He stabs her multiple times.

Then he cuts off her clothing.

He sexually assaults her.

Winston Moseley flees.

A police car pulls in.

- [Male Announcer] But it was too late.

Kitty Genovese died in the ambulance on the way to the hospital.

Her partner Mary Ann didn't hear the news until later when the police knocked on her door.

I felt, wow, she was so close and I was sleeping and I didn't know what happened, that I could have saved her.

You know, that's what I really think still.

- [Male Announcer] At first the murder was not big news, but two weeks later after a tip from police, the New York Times published a chilling front page story that began, "For more than half an hour 38 respectable, law-abiding citizens in Queens watched a killer stalk and stab a woman."

- The story was absolutely and utterly shocking.

No one could imagine that not only would people fail to call the police, but that they would watch the murder take place over half an hour.

- [Male Announcer] One witness was quoted as saying, "I didn't want to get involved."

The story became a sensation and the public reacted with disgust and fear of city life - Tell me why you felt it was necessary for you to carry a knife.

- The Kitty Genovese case, where no one came to her rescue even though she begged for help.

- 38 of her neighbors watched a woman die and when it was over they all went back to bed.

- In the aftermath of the murder, the 38 witnesses who were not involved in Kitty's murder but were only witnesses to it had been portrayed almost worse than the murderer himself.

- [Male Announcer] 29-year old Winston Moseley was picked up by the police and confessed to the killing.

- The detectives asked the killer, how could you attack this woman in front of so many witnesses?

Weren't you afraid?

And the killer said I knew they wouldn't do anything.

People never do.

- [Male Announcer] Genovese's death became a metaphor for public apathy and moral decay.

But two young social psychologists, John Darley from NYU and Bibb Latane from Columbia University had a different take.

- Perhaps Kitty Genovese might have been alive today if fewer people had seen her.

- [Male Announcer] Their idea became known as the bystander effect.

- What struck me and struck John as we talked about it is that 38 might not have been just a coincidence.

It might have been a cause.

It might have been what made it happen, that it might have been that each of the people was actually concerned but somehow was mislead by the idea that other people were watching.

- [Male Announcer] Using students, Latane and Darley designed experiments to test their counterintuitive theory that the more people who witness an emergency, the less likely it is that any of them will intervene.

- [Experimenter] We'd like to thank the two of you for being here today.

- [Male Announcer] A student was told she was speaking privately over an intercom with one other student who suddenly said he was having a seizure.

- [Male Student] If somebody would give me a little help.

- Hello.

- [Male Announcer] She quickly got up and ran for help as did most of the subjects who thought that they alone knew someone was in trouble.

- Anybody here?

Help, we need some help.

We've got somebody hurt.

Hello.

- [Male Announcer] But look what happened when students were told there were others listening to the conversation.

- [Male Student] Somebody give me a little help here.

I'm having a real problem right now.

- [Male Announcer] In repeated experiments, the majority of them just sat there and didn't help.

- You think that if there are many people who witness something that other people certainly already have done something.

Why should it be me?

- [Male Announcer] New evidence in the Kitty Genovese case has emerged showing that details of that shocking New York Times story were exaggerated.

Two neighbors did call the police, and while dozens heard her screams, only a few actually saw the attack take place.

- We can look back and say that it wasn't entirely accurate, but the fact is that it was a powerful change agent for society.

- [Operator] 911 emergency.

- [Male Announcer] In the wake of the murder, the 911 phone system was created to make it easier to report a crime, and more states passed good samaritan laws to encourage people to help.

But tougher measures so-called duty to assist laws are not wide-spread.

- It's the law in many, if not most states, that there is no criminal penalty for failing to get involved, for failing to help someone who's in dire straits or in an emergency.

- [Female Newscaster] Others watching the violence take out their cell phones and record it without intervening.

- [Male Announcer] But the age of violent videos taken by bystanders has led to calls for new kinds of laws.

(screaming) - [Male Announcer] That happened in California after a 14-year old boy suffered a concussion during an assault by one teen while another filmed it and posted it on Snapchat.

- Why would you do this?

For a laugh?

For a like?

- [Male Announcer] The boy who threw the punch was given probation.

The teen who filmed it was not charged.

- Taking someone's worst moment and making it your best moment on social media is expanding exponentially and we need to do something about it now before it gets out of control.

- [Male Announcer] California has since passed a law that allows additional jail time for those who take part in a crime and video record it, but what about those watching online?

- Viewing things around rape and beatings and murder are extreme cases that are actually rare on social media, but what do you do when you see negative things?

Should you report it like you would a physical situation?

Could you call 911?

Should you call community based organization?

I think that police and schools and parents and technology companies could come together and really put forth some ideas on what people should do.

- [Male Announcer] Under fire for not anticipating how its platform would be used, Facebook has hired thousands of people to remove offensive material faster so its users don't become unwitting bystanders to violence.

- We will keep doing all we can to prevent tragedies like this from happening.

- [Male Announcer] But social scientists say the bystander effect taught in textbooks worldwide is a much broader phenomenon as ingrained in us today as when it came to light 55 years ago in the Kitty Genovese case.

- What we now understand is that it's observation and now knowing what to do is something that we've done for a really long time and that technology has not shifted that.

It just puts a finer point on what we've already been doing, and I think we should stop there and think about why are kids doing this to other kids?

And social media gives us an opportunity to really dig into that.

And so that's where I think our attention should be at this moment.