It takes plenty of characters to build a Law and Order: Special Victims Unit plot: good guys, bad guys, cops, bartender witnesses. But it could be some of the most minor roles that make a difference to the viewer, according to new research from Washington State University Communications Professor Stacey Hust.

People who watch crime dramas like Law and Order or CSI are more likely to step in if they see someone being sexually assaulted, according to Hust’s study, funded by WSU, co-authored with Emily Garrigues Marett of Mississippi State University, and published in January’s Journal of Health Communication

The TV shows, some of the most common in prime-time lineups, often emphasize the importance of witnesses stepping into help, Hust says, teaching viewers that’s good behavior. In one SVU episode cited, detectives scold a group of high school students for not calling 911 when a friend suffered alcohol poisoning because they were afraid of getting in trouble for drinking. In another, police praise witnesses who shout at a man raping a woman and then chase him down a subway platform. While the intervention usually isn’t enough (there wouldn’t be a show without a victim), the portrayals have impact.

“These programs expose people to incidents of sexual assault, and they are able to identify that it’s a crime,” Hust says. “Exposure to crime dramas tells us there’s something wrong with this, and that it’s not appropriate behavior.”

The researchers surveyed 462 college students about whether they watched crime dramas and how likely they thought they’d be to intervene if they saw someone being sexually assaulted, with questions like, “If my friend was in an uncomfortable sexual situation at a party, I would make sure he/she is OK,” and “If I saw a drug being slipped into someone’s drink, I would warn that person.” They also asked about self-confidence and physical skill level, factors already proven to increase someone’s likelihood to intervene, and controlled for those.

If researchers can identify what about TV plots encourages people to intervene, advocates could use those techniques in educating the public, Hust says. And, she adds, TV writers could write more intervention into their stories.

“Bystander intervention is key to sexual assault reduction because it creates an environment where [assault] is not tolerated,” Hust says. “If we see on television that doing this behavior is going to get us praise, acceptance and value among our peers, we’re more likely to do it in our own life."