ior (Parker 1974, Enquist & Leimar 1983, McNamara & Houston 1986, Milinski 1987, Fudenberg & Tirole 1991, Binmore 1994, Hammerstein Sc Selten 1994, Ohtsuki & Iwasa 2004, Nowak St Sigmund 2005). Understanding the evolution of animal communication and human language requires evolutionary game theory (Nowak & Krakauer