You probably remember the disturbing story reported last week about a 15-year-old high school student in northern California being gang-raped at her homecoming dance. Equally horrific, perhaps, is the fact that as many as two dozen people stood by and did nothing while the girl was assaulted. Why do many people stand by and do nothing when they see a crime being committed? Is it just out of fear that they too might become a victim, or be attacked? Sharyn Potter is a Professor of Sociology at the University of New Hampshire and has done a lot of work on so-called 'bystander phenomena' as it relates to sexual assaults.

Potter says a big factor in this tendency towards inaction when witnessing this kind of assault is the large number of what she calls 'rape-myths' that continue to be perpetuated in our society.

Sharyn Potter: In our culture we tend to blame victims of rape. So there's a lot of misinformation tied up in people's attitudes.

Tom Porter: Could it not be that the bystanders were afraid to intervene as this could put them in danger?

SP: Right, but in this day of the cell-phone age it's really easy for somebody to hide behind a bush or something and very discreetly call 911 or text for help.

TP: So when this girl was being assaulted, because it was of a sexual nature, people felt that somehow they should not get involved?

SP: I don't know that, but there was a lot of people, and when there's a lot of people, the responsibility tends to diffuse. Maybe people tend not to feel as responsible when they do not know the victim.

TP: So there's an inverse proportion between the number of witnesses and likelihood of somebody doing something -- the more people are onlooking, the less likely something's going to happen?

SP: That's what the research has shown.

TP: But what exactly is it that tends to dissuade people from acting?

SP: Well we have these media images that continue to objectify women and equate sexuality and violence and condone the use of force and coercion in a relationship, so we're living in a really complicated culture.

TP: So what are you doing to try and encourage people to help in these situations?

SP: We have developed at UNH a 'Bringing in the Bystander' program and social marketing program, and we train people to be what we refer to as 'pro-social bystanders' -- how can you help a victim without being involved as a bystander, without being hurt.

TP: So you mentioned cellphones, is it as simple as just getting on the phone and dialing 9-1-1 and describing what you're seeing?

SP: Right, and leaving it to the authorities who are trained to handle situations like that. We're not advocating for a bystander to go into a situation where they could become hurt.

TP: What are some of the key things you've been learning from this Bringing in the Bystander program that you've been running - not just at UNH but in schools and communities across the country?

SP: We have a prevention program where students are educated about the problems of sexual violence and actually learn about the role of bystanders and prevention and are able to practice through role-playing, and what we've found is that students that participate in the in-person program are much more confident and report that they've actually acted in a bystander role when they've seen sexual violence occuring, or about to occur or has occured.

TP: You're saying you have noticed a definite increase in people intervening in situations where they wouldn't have intervened before because of the work you've done?

SP: That's what they report in the research we've been collecting.

Sharyn Potter is Associate Professor of Sociology at the University of New Hampshire.