This is a remarkable six minutes, thre final round of a British game show, "Golden Balls." Please watch before reading my comments below:
So, I found this on Boing Boing, which led to a blog post with some astute comments by Bruce Schneier and his followers, but I'll just sum up my own quick take on this usurping of the classic Prisoner's Dilemma.
1. Nick's confidence helps "sell" his choice to Ibrahim. Nick is not swayed by Ibrahim's appeal to reason or honor, or to his complete confusion and despair. Nick says what he will do and leaves no doubt that he will do it: he says he will STEAL and split the money after the show; Ibrahim has no choice but to take him at his word about the former and guess about the latter.
2. Ibrahim's choice is now whether to believe Nick, choose SPLIT, and hope Nick sticks to his promise to split the funds after the show, or to spite Nick, choose STEAL, and assume they both end up with nothing. Nick seems entirely resigned to this possibility.
3. Nick's choice of SPLIT is absolutely brilliant. If Ibrahim chooses SPLIT, which Nick is clearly confident is Ibrahim's only rational choice, then trust is restored and the money is split. But, if Ibrahim chooses STEAL (and thus gets all the money), he would have little honorable choice but to do what Nick proposed anyway: split the money after the show. (That's not 100%, but especially given what Ibrahim said about honor, it's seems overwhelmingly likely that Ibrahim would do that.)
4. As someone on Bruce Scheier's blog said, Nick is essentially saying "I don't trust you; you must trust me or lose all."
5. It's unclear if this would ever work again.