McDonald's is challenging people not to get distracted by a Big Mac in a digital campaign to accompany its current TV spots in which professionals find the burger hijacks their thoughts. The work, by Razorfish, kicks off with this viral video of a hidden camera prank, in which unsuspecting people are asked to take a photograph of a couple. While a poster of a Big Mac is carried past them, the girlfriend of the couple changes places with another girl, and they appear not to notice. Viewers can click through to a website in which Big Mac challenges you to a series of mind games -- to see whether you, too, are distracted by the product.