Bigger Head, Smarter Baby?
Study: Babies' Brain Volume by 1st Birthday May Affect Child's Intelligence
Oct. 13, 2006 -- A child's intelligence may partly be reflected by how much
his or her head grows by age 1.
That news comes from researchers in England including Catherine Gale, PhD,
of the University of Southampton.
"The brain volume a child achieves by the age of 1 year helps determine
later intelligence," Gale and colleagues write in the October edition of
The researchers don't know exactly what causes some babies to have bigger
brains than others. They also stress that many factors, including parent-child
relationships, may affect kids' intelligence.
Head growth -- especially in infancy -- may be one of those factors, the
Gale's team studied 633 full-term British babies.
The researchers used a tape measure to gauge the babies' head circumference
at birth, one year, four years, and eight years.
The children took IQ tests when they were 4 years old and 8 years old. Those
with the biggest heads tended to have the highest IQ scores.
The researchers found that head growth by age 1 was the key factor. Catch-up
growth didn't matter as much.
"Brain growth after infancy, at least in terms of brain volume, is
unlikely to compensate for poor growth in the first year of life," the
The researchers also studied the babies' parents.
The babies' mothers completed surveys about their parentingstyle, their older children, and other factors such as breastfeeding and postpartum
The researchers gave each mother a parenting score based on the survey
The babies tended to have higher IQ scores if their parents had more
education, had been breastfed for three or more months, and had mothers with
high scores on the parenting questionnaire.
Even after adjusting for all those factors, babies' head growth by age 1
remained tied to IQ scores among the 4- and 8-year-olds.
"Our findings provide additional evidence that infancy is the most
important period of postnatal brain growth for determining later
intelligence," the researchers write.