Nickelodeon, via Associated Press

New research on children and television has put SpongeBob Squarepants on the hot seat.

Researchers report that 4-year-olds who had just watched the fast-paced fantasy cartoon “SpongeBob SquarePants” — which follows the undersea adventures of a yellow sponge — did worse on tests of attention and problem-solving than young children who watched a slower-paced educational program or spent time drawing.

Officials from Nickelodeon, the network that produces “SpongeBob,” dismissed the significance of the study, saying in a statement that preschool-age children are not the show’s intended audience. “SpongeBob” is designed for 6- to 11-year-olds, according to the network, which questioned the study’s small sample size of white middle- and upper-middle-class children.

The study, which appeared in the Sept. 12 issue of the journal Pediatrics, involved 60 children whose parents reported similar levels of television-watching and attention skills. The children were randomly assigned to one of three groups: one watched nine minutes of the cartoon, another viewed nine minutes of the educational program “Caillou,” and the remaining group spent the time with drawing paper, markers and crayons.

The tests were administered immediately after the children watched the program and were designed to assess what is known as children’s executive function, which underlies attention, working memory, problem-solving and the delay of gratification. The children were given tasks that involved following instructions, reversing the order of numbers and resisting treats.

“The children who watched the cartoon were operating at half the capacity compared to other children,” said Angeline S. Lillard, a professor of psychology at the University of Virginia and one of the paper’s authors.

She said the effect was not specific to “SpongeBob SquarePants” and has also been demonstrated with other fast-paced cartoons in which “there are lot of things happening that can’t happen in real life — magical things going on in totally new places, the bed catapults you out and you land in a lake wearing an astronaut costume — and happen in fast succession.”

“There is so much stuff that’s hard to assimilate, it might be disrupting the child’s thinking process, so they may not be able to grasp the messages that are educational,” Dr. Lillard said. “This suggests the brain is working very hard to register it all and gets exhausted afterward.”

Asked whether the fatigue might indicate that some kind of learning had occurred while watching “SpongeBob SquarePants,” she said the random and unpredictable nature of the cartoon was more likely to “disrupt the ability to focus rather than strengthen it.”

The study is one of the first to use a control group and randomization to try to gauge the impact of different types of television on children, and to look at the type of show rather than the amount of television watched, said Dr. Dimitri A. Christakis, director of behavior and development at Seattle Children’s Research Institute, who wrote an accompanying editorial.

“It’s important for parents to know that not all viewing is the same. It’s not just about turning the TV off, but about changing the channel,” Dr. Christakis said.

He noted that the study had “notable weaknesses,” including its small sample size and the lack of adequate blinding. In addition, the children were not assessed before the viewing and drawing, relying instead on parental reports.

But the findings, Dr. Christakis says, could have “profound implications for children’s cognitive and social development.” In his editorial, though, he notes that “there is a competing school of thought that the digital-native generation is becoming acculturated in ways that will make it well suited to the fast-paced world they will grow to inherit.”

Television viewing data show that Sponge Bob is watched by very young children. During the past 8 months, 1.74 million children aged 14 and younger have watched the show. Among those viewers, 39 percent were between the ages of 2 and 5, according to Nielsen.

The American Academy of Pediatrics discourages television for children under 2, recommending other activities like reading, playing, singing and talking with a child, and it suggests limiting older children to no more than two hours of total entertainment media time, preferably of high-quality programming.

“As parents, we often assume that if it’s a cartoon, it’s fine,” Dr. Rahil Briggs, a psychologist and director of the Healthy Steps Program at Children’s Hospital at Montefiore in the Bronx said in commenting on the study.

But she said the fast-paced fantastical sequences of some programs might actually prime the early childhood brain to “not be able to pay attention to something that is not so fantastic. You may be priming the brain to be almost A.D.H.D.-like impulsive.”