We study individuals who can choose how to compete with an opponent for one nonzero payoff. They can either nudge themselves into a fair set of rules where they have the same information and actions as their opponent, or into unfair rules where they spy, sabotage or fabricate their opponent's...

We investigate the role of intentions in two-player two-stage games. For this purpose we systematically vary the set of opportunity sets the first mover can chose from and study how the second mover reacts not only to opportunities of gains but also of losses created by the choice of the first...