In the video showing the killing of George Floyd by police, three officers stood by and watched as their colleague, Derek Chauvin, kneeled on George Floyd's neck for eight minutes and 46 seconds.
The incident almost two months ago sparked national protests across the country and evoked memories for some of the beating of Rodney King by police in Los Angeles in 1992.
Why is it that when police violence happens, other officers are often just standing by and watching rather than intervening?
We ask Ervin Staub, a professor emeritus of psychology and the founding director with UMass Amherst's "The Psychology of Peace and Violence Program."
Staub has spent his life working to understand the roots of good and evil; and how acts of violence, like genocide and mass killings, are allowed to happen.
He developed "active bystander" police training, so officers can stop their colleagues from doing unnecessary harm. This training has been implemented in New Orleans.
On why the issue of police brutality has been so difficult to solve:
Well, there are many reasons for it. One of them is that the police culture is such that officers are expected by other officers and by their superior officers to support their fellow officer no matter what that officer does.
So if that officer engages in some kind of unnecessary harmful behavior, other officers are expected either to support it actively or passively stand by. But not to go contrary to it. And that is a serious problem. It's part of how police divides the world between us, the police and the rest of the world. And that becomes a problem, of course.
On bystander training - "EPIC" - for police departments:
Well, the training is based on two kinds of research that I have done. One: research in laboratory environments - like at the university - where people hear sounds of distress from another room ... Depending on what that person says, the behavior of the other person varies a great deal. If somebody defines the situation as an emergency - as a need for help - and calls that other person for help, everybody helps.
I also studied what happens in mass violence, mass killing, and genocide. People, individuals or groups, when they engage in harmful behavior, they change as a result of their own actions. So that violence evolves, becomes more intense, and it's only prohibitive influences - like active bystanders who exert powerful influence - that stops this evolution.
So I used these to create both an understanding on the part of police officers — of what leads them to engage in unnecessary violence, of what is necessary in order to inhibit that — and also what are the benefits when they do that.
On "bad apples" and if they can be trained out of the environment:
There is only one way to train out the bad apples, and that is to create a department. And this training can do that. It makes such behavior unacceptable. If a so-called bad apple knows that other officers will intervene and not accept such behavior, when the whole climate in that police unit changes, then it becomes much less likely that bad apples do bad things. So it's not like necessarily that the nature of that officer will change, but it is the understanding of that officer, of that environment, and what is acceptable and unacceptable that can change.
You could say that in a department and most departments where other officers remain passive that everybody's a bad apple. Seeing an officer do really harmful behavior to someone when it is not necessary and remaining passive - that means that you are a bad apple... Some of these people are good people, but the culture and their training and their experience makes them remain passive. That turns them into bad apples. So we can transform that. We can change that. And the climate that develops can be transformative.
This segment aired on June 24, 2020.