Recently, a study revealed that parents should really limit the amount of screen time that their children have to just two hours a day, especially since an increasing body of research suggests that all that eye strain is causing a disturbing rise in nearsightedness in both kids and adults. Now, a new study published in the journal Social Science Research states that, if you want to have a sharp kid, the best thing you can do is not only encourage them to read real books, but also keep a fair number of them around the house.
最近，一项研究揭示：家长应限制孩子看屏幕的时间，每天最多看俩小时，特别是因为越来越多的研究表明：眼睛疲劳会导致宝宝和成年人都近视。现在，《社会科学研究》（Social Science Research）期刊上发表的一项新研究指出，若想培养聪明宝宝，不仅要让他/她多读书，而且家中也要多备些书。

Researchers asked 160,000 adults, from 31 different countries, who took part in the Programme for the International Assessment of Adult Competencies between 2011 and 2015, how many books were present in their homes when they were growing up. They then compared these responses to the results of a series of tests the participants took to measure their literacy, numeracy, and information communication technology (ICT) skills.
来自31个不同国家的16万成年人参加了成人能力国际评估计划（2011至2015年），研究员请这些成年人回答了这样一个问题：在成长过程中，你家里面有多少书？之后，研究员将受试者的回答与他们所进行的一系列测试结果进行对比，以评估他们在识字、算术和信息通信技术方面的技能。

What they found was that those who grew up with almost no books in their homes scored below average on literacy tests, while those who had about 80 in their houses by the time they were teenagers scored about average. The positive correlation between the number of books in the house and literacy levels continued to rise after 80, but plateaued after 350.
他们发现：成长过程中家中几乎没有书的成年人在识字测试中的得分低于平均水平，而青少年时期家中约有80本书的成年人的得分大约是平均水平。当家中书的数量超过80本时，家中书的数量与识字水平的正相关性继续上升，直至书的数量达到350本时趋于持平。

"Adolescent exposure to books is an integral part of social practices that foster long-term cognitive competencies spanning literacy, numeracy, and ICT skills," wrote Dr. Joanna Sikora, a senior lecturer in sociology at Australian National University. "Growing up with home libraries boosts adult skills in these areas beyond the benefits accrued from parental education or own educational or occupational attainment."
"青少年接触书籍是社会实践中不可缺少的一部分，可在识字、算术和信息通信技术等技能方面培养长期的认知能力，"澳大利亚国立大学的社会学高级讲师乔安娜·西科拉博士写道。"在藏书颇多的家庭中成长可以提高成年人的这些技巧，其益处超过了父母教育或自学或职业成就带来的益处。

In addition, the paper argues that, for now at least, there's not enough evidence to suggest that the literacy gains of print books can be replaced with e-books consumed on an iPad.
此外，该文章认为：至少到目前为止，还没有足够的证据可以表明印刷书籍提升的识字能力可以被iPad上的电子书所取代。