The recent fashion for eating on the hoof rather than sitting round the family dinner table is having a detrimental effect on children's ability to speak and communicate, according to Harvard researchers.
An eight-year study by the Harvard University Graduate School of Education has found that children who participate in mealtime discussions later show the highest aptitude for reading and vocabulary.
The researchers put tape recorders inside backpacks strapped to 80 children, beginning at age three, and on the children's dinner tables. They found that conversations at the evening meal used about 10 times more sophisticated words than other situations, including school and play time.
"Parents probably see the mealtime discussion as a time for socialisation more than education," said Catherine Snow, a Harvard language development authority who headed the $1.2 million (Pounds 800,000) study.
"If they think about it at all, they think of it as a place to make contact with their children's lives. But that's precisely the type of dialogue that generates vocabulary."
Dr Snow said people use the dinner hour to swap news about their day. Meal times, the study found, often consist of lively conversations about past events, future plans and examinations of how the world works. Children therefore can relate to it, absorbing complex vocabulary.
"It serves so many purposes at once because it introduces a certain regularity into children's lives while parents can relieve themselves of some of the strains of daily life," Dr Snow said. "At the same time it has this remarkable effect on children's vocabulary."
And it's free, she said; there's no need to buy books, educational toys or software.
"Some of the families we studied never managed to produce a tape of a dinner table conversation for us, presumably because this wasn't something that was going on every night," Dr Snow said. "The parents may be working late and the kids have after-school activities. But even if it's not a regular phenomenon, every little bit helps. So if it's once a week, that's better than once a month, and twice a week is better than once a week, but once a month is better than nothing."