A video posted on social media showing a violent altercation between two students in the Fredericton area is being investigated by police and school officials.

The fight happened this week between two students at Leo Hayes High School. The video appears to show one girl trying to incite a fight, while another didn’t want to take part.

There are several students spectating, but none intervene. Psychologists say it's a well-known phenomenon called the bystander effect.

“There's lots of things psychologically that go on for people who are watching something horrible happen, and they're often afraid of intervening because (they think) maybe that aggression I'm seeing will become directed towards me. Maybe I will become the one who is socially excluded," says Mary-Ann Campbell of the University of New Brunswick Saint John Centre for Criminal Justice Studies.

In the days before social media, schoolyard fights and incidents of bullying may have had a shorter lifespan, but now they have the potential to live on forever on the Internet.

Sgt. David Hartley Brown, who organizes anti-bully programs for Saint Johnarea schools, says most teens don't understand the long-term consequences of being linked to these kinds of violent incidents.

“Maybe 20 years ago we could have resolved it so much simpler, but that's not the way the world works," says Sgt. Hartley Brown. “They're not really thinking that far ahead about the possibilities, how this will reflect on their own character and their own self-worth down the road.”

Sgt. Hartley Brown says by taking cellphone video and sharing it online, the bullying victim is being re-victimized by her peers.

"Without really appreciating what is going on in that video, or what the significance is for the people that are getting hurt in it. That's quite typical of adolescents," he said.

No charges have been laid in the incident.

With files from CTV Atlantic’s Mike Cameron.