BEIJING • Children in rural areas of China have lower-than-average IQs, a Stanford University study has shown.

Lack of access to books and a poor diet are two reasons cited by the researchers. Only about 5 per cent of parents in the rural areas surveyed read books to their children, and 70 per cent of the families there possessed only one book or no books at all.

This affected the children's cognitive development, reported Caixin news website.

Mr Scott Rozelle, who is co-director of the university's Rural Education Action Programme, told Caixin that more than half of those aged between 24 and 30 months and about 40 per cent of those aged between six and 18 months scored below average in IQ tests.

Caixin did not give the IQ scores for children residing in the rural areas covered, but quoted Mr Rozelle, who said that the average IQ scores for these age groups should range between 90 and 109.

The situation in rural areas could hold back plans to transform the Chinese economy into one driven by services and technology.

"Ultimately, if China becomes a high-wage, high-income society, a large share of these children will be unemployable," said Mr Rozelle.

The study monitored the development of 2,500 children across Shaanxi, Hebei and Yunnan provinces last year.

"Chinese families love their children but don't know much about parenting," Mr Rozelle told Caixin.

"They think reading a book or singing to their babies is silly because they think: 'They're just babies'."

Many of these rural kids are known as "left-behind children". Their migrant-worker parents spend most of the year elsewhere, earning a living in China's coastal cities.