12/17/2014 03:03 EST | Updated 02/16/2015 05:59 EST

Frozen, other on-screen deaths in animated films may upset young children

Children’s animated films such as Frozen and Finding Nemo are rife with murder, says an Ottawa researcher whose own young kids begged him to stop a video about cute cartoon dinosaurs.

The study, titled Cartoons Kill, was published in the Christmas issue of the BMJ, which is devoted to tongue-in-cheek medical research.

Ian Coleman, a mental health epidemiologist at the University of Ottawa, and his co-authors looked at the length of time it takes for key characters to die in top-grossing children’s cartoons ranging from Snow White in 1937 to Frozen in 2013. The kids' films were compared with top-grossing dramatic films for adults such as The Exorcism of Emily Rose and Pulp Fiction.

"I've got two young kids myself, and I started watching these films, and my kids have been quite honestly traumatized by a few of them," Colman said of his four-year-old son and six-year-old daughter.

 "We tried watching The Land Before Time, which seems pretty innocent. You've got these cute little cartoon dinosaurs, but the mother of the main character gets savagely attacked and killed by a Tyrannosaurus rex in the first five minutes of the film. And at that point my daughter [about age four at the time] was just completely hysterical and begging me to stop the film.

"And when we saw something similar in Finding Nemo, we really started to think maybe there's something going on here."

In the study, notable early on-screen deaths included:

- Nemo’s mother being eaten by a barracuda 4 minutes and 3 seconds into Finding Nemo.

- Tarzan’s parents being killed by a leopard 4 minutes and 8 seconds into Tarzan.

- Cecil Gaines’s father being shot in front of him 6 minutes into The Butler.

In Frozen, the most recent example, both parents of the main princess characters drown when their ship sinks 10 minutes into the film.

Age to understand death

Two-thirds of children’s animated films contained on-screen death of a key character compared with half of the adult films, the researchers found.

"We conclude that children's animated films, rather than being innocuous alternatives to the gore and carnage typical of American films, are in fact hotbeds of murder and mayhem," they wrote.

The issue is that before the age of 10, children may have only a partial understanding of death.

Dr. Sandra Mendlowitz, a psychologist in the anxiety program at Toronto's Hospital for Sick Children, said the idea that characters come back to life after such normally fatal acts, such as Wile E. Coyote’s adventures on the Road Runner, represents a distortion of reality that doesn't allow children to process the concept of death or understand its finality.

Death of main character can also be troubling for young kids, she said.

"The problem is that if you see a lot of violence you can become very frightened or traumatized, or you can become less sensitive to violence and the longer-term effects are the potential to behave aggressively," Mendlowitz  said.

Mendlowitz advised parents to watch animated films with their child so they can monitor and explain any content that leads children to be confused or upset.

In the study, there was no evidence to suggest the results have changed since Snow White's stepmother, the evil queen, was struck by lightning, forced off a cliff and crushed by a boulder while being chased by seven dwarves.

The researchers joked "despite all the carnage, data collection was most enjoyable."