In the \textit{machine game} invented by \textit{A. Rubinstein} [J. Econ. Theory 39, 83--96 (1986; Zbl 0606.68050)], two players pick a finite automaton each and let the automata play a repeated game of Prisoners' Dilemma against each other. In the paper under review, the author considers machine games with a payoff function based on expected mean stage payoff and proves that the only evolutionary stable strategy of this game is DEFECT, the automaton that defects regardless of what the opponent does. He has related results on stochastic stability (as introduced by \textit{D. Foster} and \textit{P. Young} [Theor. Popul. Biol. 38, 219--232 (1990; Zbl 0703.92015)], and connects his research to related and yet different results (using different utility and cost functions) due to \textit{K. G. Binmore} and \textit{L. Samuelson} [J. Econ. Theory 57, 278-305 (1992; Zbl 0767.90095)] and \textit{D. J. Cooper} [J. Econ. Theory 68, 266--275 (1996; Zbl 0849.90137)].