“A room without books is like a body without a soul,” observed the Roman philosopher, Cicero. It can also be a sign of financial hardship to come.

New research has uncovered a strong correlation between the earnings of adults and whether they grew up surrounded by books as children.

Three economists at the University of Padua – Giorgio Brunello, Guglielmo Weber and Christoph Weiss – studied 6,000 men born in nine European countries and concluded that children with access to books could expect to earn materially more than those who grow up with few or no books.

They studied the period from 1920 to 1956, when school reforms saw the minimum school leaving age raised across Europe. They looked at whether, at the age of 10, a child lived in a house with fewer than 10 books, a shelf of books, a bookcase with up to 100 books, two bookcases, or more than two bookcases.

Over the period studied, the research, published in the Economic Journal, found that an additional year of education increased a man’s average lifetime earnings by 9%. But the returns varied markedly according to socio-economic background.

Men brought up in households with less than a shelf of books earned only 5% more as a result of the extra year’s education, compared with 21% more for those who had access to a lot of books. And those that had access to books were more likely to move to the better-earning opportunities in cities than those without books.

The men’s first job was also much more likely to be a white-collar job.

The economists offer a number of theories for the results. “Perhaps books matter because they encourage children to read more and reading can have positive effects on school performance. Alternatively, a home filled with books indicates advantageous socio-economic conditions.”

The number of books in a child’s home can effectively predict their cognitive test scores. This may indicate a home that encourages cognitive and socio-emotional skills, which are important for economic success in life.