article_snippet: But the reasons why people are becoming smarter is not known - with theories including better education and improved medical care.
article_snippet: Explanations include better education (stock image shown) and improved medical care .
article_snippet: And the gap got wider throughout childhood, with the early difference tripling by the time the children reached adolescence.
article_snippet: ‘catching up with the developed world’.
article_snippet: These include improved education, increased exposure to testing, improved medical care and nutritition and decreased family size.
highlights_snippet: Explanations include better education and improved medical care .