Professor Ben Polak: So last time we introduced a new idea and the new idea was that of best response.
And what was the idea?
The idea was to think of a strategy that is the best you can do, given your belief about what the other people are doing: what your opponents are doing, what other players are doing.
And you could think of this ─ you could think of this belief as the belief that rationalizes that choice.
So if you have a boss you might want to ─ and he or she is going to ask you why you chose the action you did.
If you took a best response to some believe, you can say I took this action because I believed other people are going to do this.
And since that was the best you could do under that belief, you'll hopefully keep your job.
I promised that today we would look at the most important game in the world.
And, as announced last time, the most important game is the penalty kick game.
So this is a game that occurs in soccer and just to give an idea of how important it is for those people who are unfortunate enough not to be soccer fans here, the last World Cup was decided on penalty kicks.
