Thanks for the pointer; I can imagine that fantasying should have conferred some evolutionary advantage since it is seen across all cultures in such a pervasive fashion. But, the question that Freakonomics is asking is slightly different, I guess — they are asking about returns for the investment in fantasy films and books. As Oliver Sacks said elsewhere, one answer of course is that it gives so much of pleasure and what more can one ask for. But are there any other benefits other than that they give us pleasure? Could be; but I don’t know what they are.

“For human beings the really important evolutionary advantage is our ability to create new worlds. Look around the room you’re sitting in. Every object in that room – the right angle table, the book, the paper, the computer screen, the ceramic cup was once imaginary. Not a thing in the room existed in the pleistocene. Every one of them started out as an imaginary fantasy in someone’s mind. And that’s even more true of people – all the things I am, a scientist, a philosopher, an atheist, a feminist, all those kinds of people started out as imaginary ideas too: