Combination with anti-tit-for-tat remedies problems of tit-for-tat.
One of the most important questions in game theory concerns how mutual cooperation can be achieved and maintained in a social dilemma. In Axelrod's tournaments of the iterated prisoner's dilemma, Tit-for-Tat (TFT) demonstrated the role of reciprocity in the emergence of cooperation. However, the stability of TFT does not hold in the presence of implementation error, and a TFT population is prone to neutral drift to unconditional cooperation, which eventually invites defectors. We argue that a combination of TFT and anti-TFT (ATFT) overcomes these difficulties in a noisy environment, provided that ATFT is defined as choosing the opposite to the opponent's last move. According to this TFT-ATFT strategy, a player normally uses TFT; turns to ATFT upon recognizing his or her own error; returns to TFT either when mutual cooperation is recovered or when the opponent unilaterally defects twice in a row. The proposed strategy provides simple and deterministic behavioral rules for correcting implementation error in a way that cannot be exploited by the opponent, and suppresses the neutral drift to unconditional cooperation.
Department of Physics and Astronomy, Seoul National University, Seoul 08826, Republic of Korea.
Su Do
SD
Yi
Department of Physics, Pukyong National University, Busan 48513, Republic of Korea. Electronic address: seungki@pknu.ac.kr.
Seung Ki
SK
Baek
School of Economics and Trade, Kyungpook National University, Daegu 41566, Republic of Korea. Electronic address: jkchoi@knu.ac.kr.
Jung-Kyoo
JK
Choi
D005716:Game Theory; D008962:Models, Theoretical
Evolution of cooperation; Memory; Prisoner's dilemma; Reciprocity