But new research that involved the largest study ever done with real conflicts captured on CCTV shows strangers almost always step up to intervene on behalf of victims in public.
"According to conventional wisdom, non-involvement is the default response of bystanders during public emergencies," said Dr. Richard Philpot of Lancaster University and the University of Copenhagen, who co-authored the study published in American Psychologist. "Challenging this view... video data shows that intervention is the norm in actual aggressive conflicts."
A team of European researchers reviewed 219 arguments and assaults caught on surveillance cameras in Amsterdam, Lancaster and Cape Town. They found that bystanders who witnessed the incidents intervened in 91 percent of the situations.
Usually not just one, but several bystanders intervened in one or more ways, including gesturing for an aggressor to calm down, physically trying to separate the perpetrator from the victim or consoling the victim.
"The fact that bystanders are much more active than we think is a positive and reassuring story for potential victims of violence and the public as a whole," Philpot added. "We need to develop crime prevention efforts which build on the willingness of bystanders to intervene."
The research also found, perhaps not surprisingly, that the presence of more bystanders increased the likelihood that a victim would receive help.
Also interesting was the finding that the helping rate was consistent across the three locales, even though Cape Town is often perceived as a more dangerous city.
The study concludes that this validates earlier research "suggesting that third-party conflict resolution is a human universal, with a plausible evolutionary basis."
In other words, the idea that we live in a "walk-on by society" doesn't match the tape. Instead, it seems we might have evolved to help each other.