NEW YORK (CNN) — Parents would undoubtedly give the TV rating system in the United States a terrible review.

That's the basic conclusion of a new study published in the journal Pediatrics, which revealed that violence is prevalent across shows, regardless of rating. TV-Y7 rated shows, intended for kids age 7 and older, had similar levels of violence as TV-MA shows — mature audiences only — even if the Dartmouth researchers discovered lower levels of sex, alcohol and tobacco on TV-Y7 shows compared to the shows for older audiences.

"From prior research, we know that youth between 8 and 18 years consume, on average, 7.5 hours a day of media content," said Joy Gabrielli, lead author of the study and a clinical child psychologist at the Geisel School of Medicine at Dartmouth. Gabrielli said that teens and even very young children watch programs on TVs and cell phones, both from cable and the Internet — nothing like the past.

Congress mandated the development of a TV ratings system and hardware (V-chip) to allow parents to block objectionable content two decades ago through the Telecommunications Act of 1996, Gabrielli and her co-authors explained. The industry responded by establishing the TV Parental Guidelines along with a monitoring board to ensure accuracy, uniformity and consistency of the guidelines.

Violence everpresent

For the study, Gabrielli and her colleagues looked at 17 TV shows, a total of 323 episodes, across four rating categories: TV-Y7, TV-PG (parental guidance suggested), TV-14 (for teens age 14 and older) and TV-MA. Then, they content-coded the episodes, recording the total seconds of smoking, alcohol use, sexual behavior and violence, and then noted more details about the types of violence.

Drinking behaviors were coded as actual or implied, such as making a cocktail, holding a beer or a bottle of wine and filled glasses between two characters. The researcher did not code for implied smoking, where cigarette butts in an ashtray appear on screen, or implied sex, where two characters emerge from a bedroom, though they did code for sex when only sounds of intercourse were heard. Violence, defined as the use of force (or a credible threat made) by people or anthropomorphized animal characters that physically harmed animate beings, had to be intentional, so it did not include accidental contact.

Violence occurred in 70 percent of episodes overall. Sex was present in 53 percent of all episodes. Alcohol was present in 58 percent of episodes, and smoking occurred in 31 percent of episodes overall. Every show had at least one depiction of one type of risk behavior, regardless of age rating.

Related:

Screen violence — real and fictional — harmful for kids, experts say

Screen violence — which includes violence in video games, television shows and movies — is associated with aggressive behavior, aggressive thoughts and angry feelings in children, according to a policy statement released by the American Academy of Pediatrics early Monday.

Though sex, smoking and alcohol were rarely seen in TV-7 shows, violence was present in 73 percent of TV-Y7 shows.

Among specific shows, "Burn Notice" (TV-PG) contained episodes with the highest average for violence, "Californication" (TV-MA) was highest for sexual behavior and alcohol use, and "Mad Men" (TV-14) was highest for smoking, according to the study authors. "Dirty Jobs" (TV-14) was the only show with no violence.

"Indeed, 2 of the TV-Y7 shows, 'SpongeBob SquarePants' and 'The Fairly OddParents,' contained higher violence levels than were present in TV-PG, TV-14, and TV-MA shows," the researchers noted in their study.

"The networks put ratings on their own shows," said Betsy Bozdech, executive editor of reviews and ratings for Common Sense Media, adding, "Most people don't realize that, and I always like to point that out." Common Sense is a non-profit organization dedicated to helping families make smart media choices, and includes their own age-specific ratings for TV shows, movies, books and video games. Bozdech emphasized that "self-policing" — such as the networks rating their own shows — is not effective in most situations.

Ratings are important to parents because they want to protect their children from seeing a variety of bad behavior, including violence.

According to Gabrielli, the danger in violence as portrayed on TV is that it is "trivialized, glamorized and sanitized."

And, a separate 2015 study "found an association between media violence exposure and physical aggression in children." Lead author of this 2015 study, Dr. Tumaini Coker of the David Geffen School of Medicine at UCLA explained the link between exposure to violence (on TV, video games and music videos) and aggression increased with more exposure time. That said, Coker's study did not look for a cause-and-effect relationship between the two, so any aggression observed in children could come from sources other than media content.

"There's no doubt that the content that kids see in the media has an impact on them," said Bozdech. "How much of an impact depends on the age of the kid," she added, noting that "risk factors," such as home exposure to violence, can make it more likely that violence seen on TV can become a trigger for aggression.

The current study performed only a limited investigation of the ratings system — just 17 shows and all of them produced by established networks — so it is very limited, still it provided insight into how the rating system may fail parents. "The TV Parental Guidance rating system may not be effective as a standalone tool for parents who hope to limit their children's exposure to these risk behaviors," said Gabrielli.

So the question remains: If the ratings from networks are inaccurate, how do parents stay on top of the situation?

TV watching with kids

According to Common Sense Media's Bozdech, prime time and family viewing hour "went out the window years ago. That train left the station when the DVR came along," she said, noting how her own 6-year-old watches more content on an iPad than on an actual TV. She also pointed out most children have phones and devices and can watch most content there.

In this environment, parents need to teach their children how to be "thoughtful, critical media consumers," Bozdech said and that's a "real challenge." Parents watching with their children can ask questions, like, "What would happen in real life if one person hit another?"

"You can't cover your kids eyes, but you can teach them to see," said Bozdech.

Gabrielli advocates that parents watch with their kids and talk about media and risk behaviors such as alcohol use, smoking, sex and violence whenever possible.

"Most importantly, though, parents should seek to reduce their children's exposure to risk behavior in the media through setting limits on what types of TV shows, movies, video games, apps and websites kids watch or use," Gabrielli said.

The-CNN-Wire™ & © 2016 Cable News Network, Inc., a Time Warner Company. All rights reserved.

Related topics