A new study finds that young children have difficulty learning immediately after watching fast-paced television cartoons full of images and activities that are not possible in real life.

It's what some people are calling the "SpongeBob effect."

"SpongeBob SquarePants" is a cartoon character whose surreal and improbable undersea adventures are watched by children around the world.

University of Virginia researchers wanted to find out whether watching "SpongeBob" affected kids' ability to learn immediately after seeing the show.

To find out, a group of four-year-old children watched either a short video of "SpongeBob," or a slower-paced and more realistic animated show called "Caillou."

A third group of children spent time drawing instead of watching television.

Afterward, explains researcher Angeline Lillard, they all took standardized tests designed to measure their ability to concentrate, learn, and solve problems - what psychologists call "executive function."

"And what we found is that children who had been in the "SpongeBob" group were performing only about half as well as the other children. So they were at about 50 percent capacity."

The four-year-olds in this study are at a critical age, when the prefrontal cortex is still developing. That is the part of the brain where problem-solving and related functions are located.

Lillard says one reason why a show like "SpongeBob SquarePants" might affect learning is its combination of speed and content.

"It's fast-paced and it's fantastical. So the child is needing to process all this new stuff really, really fast, and it's difficult to process since it doesn't really happen in real life."

Lillard cautions that her study looked only at how young children learned immediately after watching the TV shows, so she cannot say whether watching these kinds of programs have a permanent effect on learning.

"But I would say that parents might want to think about when children watch such shows and perhaps how frequently they watch them as well because they are certainly compromised immediately afterwards."

Lillard's study is published in the journal Pediatrics.