Watching fast-paced cartoons such as SpongeBob SquarePants damages young children's concentration and behaviour, according to psychologists.

Tests showed that four-year-olds who watched just a few minutes of the popular television show were less able to solve problems and pay attention afterwards than those who saw a less frenetic programme or simply sat drawing.

Researchers say this could be because children mimic the chaotic behaviour of their favourite TV characters, or because the fast-moving and illogical cartoons make them over-excited.

As a result, they suggest that parents consider carefully which programmes they allow their offspring to watch, as well as encouraging them to enjoy more creative activities such as playing board games.

Angeline Lillard from the University of Virginia, who carried out the experiment, said, "Parents should know that children who have just watched SpongeBob Squarepants, or shows like it, might become compromised in their ability to learn and behave with self-control.

If a child has just watched a television show that has handicapped these abilities, we cannot expect the child to behave at their normal level in everyday situations.

SpongeBob SquarePants, an animated series that has been shown on the cable channel Nickelodeon since 1999, tells the tale of an "incurably optimistic and earnest" sea sponge who lives in a pineapple and works in an underwater fast food restaurant.