This is Hidden Brain, I'm Shankar Vedanta.

Early one morning in March 1964, a woman named Kiri Genovese was on her way home from the bar where she worked.

She parked her car and was walking toward her apartment building when a man attacked and killed her.

Over the years, Kiri Genovese's murder has been the focus of countless books, movies and psychology research papers.

It drew attention not only because it was a grisly crime, but because it supposedly explained a deep flaw in human nature.

The New York Times published an article that said dozens of people saw the murder or heard Kiri Genovese screaming for help, but no one intervened.

When someone did call the police, it was too late.

In the decades that followed, the case came to symbolize a psychological phenomenon known as the bystander effect.

When lots of people see something as wrong, the theory goes, each person wrongly assumes someone else will step up to help.

The net effect is that as the number of potential helpers increases, the number of people who actually help decreases.

In recent years, psychologists and journalists have reexamined the fact that the Kiri Genovese story and walked back some of the claims.

The Times has said that its initial reporting was flawed and exaggerated.

I think the power of the Kiri Genovese story lies in the fact that in everyday life, we all notice that we are not as helpful and brave as we would like to be.

We look away from people who are suffering. We cross the street to avoid an altercation.

Even when the stakes are low for personal safety, we don't extend a hand to others who need help.

This week on Hidden Brain, the curious psychology behind a phenomenon that is all around us and how understanding a quirk inside our minds can help us become the kind of people we admire.

My name is Gary Knight, I'm the CEO of the Seven Foundation, which is a media non-profit. I'm also a very keen amateur cyclist.

I first met Gary in 2009 at a journalism fellowship program. A big man with a gregarious personality, he filled every room he entered.

Gary was a photographer and had covered conflicts around the world, including in the Balkans, the Arab world and Southeast Asia.

He was a member of the iconic photo agency called Seven.

I hadn't been in touch with Gary for some years, but recently met up with him. He seemed to be moving his shoulder gingerly and I asked him what happened.

The story he told me made me think about some surprising research into the nature of kindness. We'll get to that in a moment.

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