We've known for a while that home libraries are strongly linked to children's academic achievement. What's less certain is whether the benefits they bestow have a long-term impact.
A new large-scale study, featuring data from 31 countries, reports they do indeed. It finds the advantages of growing up in a book-filled home can be measured well into adulthood.
"Adolescent exposure to books is an integral part of social practices that foster long-term cognitive competencies," writes a research team led by Joanna Sikora of Australian National University.
These reading-driven abilities not only "facilitate educational and occupational attainment," the researchers write in the journal Social Science Research. "[They] also lay a foundation for lifelong routine activities that enhance literacy and numeracy."
The researchers analyzed data from the Programme for the International Assessment of Competencies. Its surveys, taken between 2011 and 2015, featured adults (ages 25 to 65) in 31 nations, including the United States, Canada, Australia, Germany, France, Singapore, and Turkey.
All participants were asked how many books there were in their home when they were 16 years old. (One meter of shelving, they were told, holds about 40 books.) They chose from a series of options ranging from "10 or less" to "more than 500."
Literacy was defined as "the ability to read effectively to participate in society and achieve personal goals." Participants took tests that "captured a range of basic through advanced comprehension skills, from reading brief texts for a single piece of information to synthesizing information from complex texts."
Numeracy tests measured the "ability to use mathematical concepts in everyday life," while IT-related tests "assessed the ability to use digital technology to communicate with others, as well as to gather, analyze, and synthesize information."
The results suggest those volumes made a long-term difference. "Growing up with home libraries boosts adult skills in these areas beyond the benefits accrued from parental education, or [one's] own educational or occupational attainment," the researchers report.
Not surprisingly, the biggest impact was on reading ability. "The total effects of home library size on literacy are large everywhere," the researchers report.
Growing up with few books in the house was associated with below-average literacy rates, while he presence of around 80 books raised those rates to the mean. Literacy continued to increase with the number of reported books up to around 350, at which point it flattened out.
Similarly, the effects of a home library on numeracy were quite significant across the board. Its impact on technological skills was smaller but also widespread.
These results raise two interesting questions. First: Will findings like this fade as printed books become less-important sources of knowledge in the digital age?
Perhaps, Sikora and her colleagues write, but for now, "the beneficial effects of home libraries in adolescence are large and hold in many different societies, with no sign of diminution over time. Moreover, home library size is positively related to higher levels of digital literacy."
The second, broader question is: Precisely how does growing up around books produce more highly skilled adults? More research will be needed to find out, but Sikora and her colleagues note that "children emulate parents who read," and, in such an environment, acquiring knowledge via the written word often becomes a pleasurable pastime.
"Scholarly culture is a way of life," they conclude. Clearly, that pattern of behavior gets established early. Spend time as a teen pulling books off a shelf, and the resultant benefits will have a very long shelf life.