NEW YORK — Children who watch fast-paced cartoons like SpongeBob SquarePants perform worse when asked to follow rules or delay gratification than kids who spend time drawing or watching slower, educational programs, a study found.

The 4-year-old children who watched nine minutes of SpongeBob on Viacom’s Nickelodeon channel performed only half as well on tasks as those who spent the same amount of time drawing or watching Caillou, a Public Broadcasting Service educational program about a 4-year-old boy, said Angeline Lillard, lead author of Monday’s study in the journal Pediatrics.

Programs that are fast paced and feature unrealistic events may over-stimulate the brain, making it harder to trigger executive function, a process used to complete tasks, Lillard said. Children may also mimic the characters after the show ends and not concentrate.

Parents need to consider how frenetic a show is, as well as its content, when deciding what their young children watch, she said.

“We don’t know how long this effect lasts,” Lillard, a professor of psychology at the University of Virginia in Charlottesville, said in telephone interview. “It may be that children recover quickly. Certainly, immediately after, there was a strong impact particularly on the most challenging tasks.”

In the study, 60 4-year-olds were split into three groups. One group watched a truncated episode of “a very popular fantastical cartoon about an animated sponge that lives under the sea.” Another saw a truncated episode of a “realistic PBS cartoon about a typical U.S. preschool-aged boy.” The third was given paper, crayons and markers and spent the time drawing.

The children were then asked to perform four tasks such as playing games that involved following rules and an activity in which they had to delay having a snack. The researchers measured how well each child performed.

Those who watched SpongeBob performed the worst on all tasks, while overall those in the drawing group and the Caillou group performed about the same, the findings show.

“These children’s brains were actually tired from all of the stimulation, and then the expectation that they focus on something became a challenge for them,” said Dimitri Christakis, director of the Center for Child Health, Behavior and Development at Seattle Children’s Research Institute, in a telephone interview.

“Not all TV is the same,” he said. “It’s not about no television, it’s really about appropriate amounts and appropriate types of television.”

A typical preschooler spends about 4.5 hours a day watching television or DVDs, said Christakis, who wrote an accompanying commentary in the journal. Children today start watching TV at 4 months of age compared with 4 years of age in 1970, he said.

More studies and larger trials are needed to replicate these findings and determine the long-term effects on children, he said.

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Ari Brown, a pediatrician in Austin, Texas, and a member of the American Academy of Pediatrics Council on Communications and Media, said there are questions about the long-term effects on children based on the amount of television they watch, the types of shows and how the shows are structured.

“Technology is great, but we also want to explore how does that impact our kids,” said Brown, who wasn’t an author of Monday’s study, in a telephone interview. “If in fact there is some impact from chilling out, watching a fun show on immediate executive function afterward, my message to parents would be get your kids to finish their homework first before they sit down and watch TV.”