James Flynn is worried about leaving the world to millennials. As a professor at the University of Otago in New Zealand, he regularly meets bright students with enormous potential, only to find that many of them aren’t engaging with the complex past of the world around them.

“They have all these modern skills and yet they come out of university no different than the medieval peasant who is anchored in his own little world,” he tells me mid-way through our conversation. “Well, actually they are anchored in a much bigger world – the world of the present – but with no historical dimension.” The result, he thinks, is that we have overly simplistic views of current issues, leaving us open to manipulation by politicians and the media.

We are talking in the living room of his son Victor, who is a mathematician at the University of Oxford, during a flying visit from his home in New Zealand. Open on the sofa is his latest reading, Alice Munro’s Runaway, the result of a recent foray into literary criticism – again, with the hope that he can encourage younger people to look beyond their smartphone screens. “I have a second book out this year that says to young people ‘for god’s sake, you are educated, why don’t you read!’” he tells me. When he was young, he says, “girls wouldn’t date you if you hadn’t read the recent novels”.

I am here to discuss his latest book, Does Your Family Make You Smarter? It is a wide ranging conversation on the ways that human thinking has changed over time, including a mysterious rise in IQ – the “Flynn Effect” for which he is now best known – and the various competing influences that shape our intellect over our lifetime.