Children with bigger heads could be brainier than those who have smaller heads, says a new study.
Catherine Gale and colleagues at the University of Southampton studied 633 full-term British babies and used a tape measure to gauge their head circumference at birth, one year, four years, and eight years, reported the online edition of the health magazine WebMD.
The children took IQ tests when they were four years old and eight years old. Those with the biggest heads tended to have the highest IQ scores, the researchers said.
They found that head growth at age one was the key factor and catch-up growth didn't matter as much.
"A child's intelligence may partly be reflected by how much his or her head grows by the age of one," said a researcher.
The study, published in the October edition of the journal Paediatrics, could not ascertain the exact cause behind some babies having bigger brains than others.
The researchers stressed that many factors, including parent-child relationships, may affect kids' intelligence.
Head growth, especially in infancy, may be one of those factors, according to the study.
"Our findings provide additional evidence that infancy is the most important period of post-natal brain growth for determining later intelligence," said the study.