Debiasing context effects in strategic decisions: Playing against a consistent opponent can correct perceptual but not reinforcement biases

Vlaev and Chater (2006) demonstrated that the cooperativeness of previously seen prisoner’s dilemma games biases choices and predictions in the current game. These effects were: a) assimilation to the mean cooperativeness of the played games caused by action reinforcement, and b) perceptual contrast with the preceding games depending on the range and the rank order of their cooperativeness. We demonstrate that, when playing against choice strategies that are not biased by such factors, perceptual biases disappear and only assimilation bias caused by reinforcement persists. This suggests that reinforcement learning is a powerful source of inconsistency in strategic interaction, which may not be eliminated even if the other players are unbiased and the markets are efficient.