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New Variations for Strategy Set-shifting in the Rat
Published on: January 23, 2017
Tit-for-tat or win-stay, lose-shift?
Lorens A Imhof1, Drew Fudenberg, Martin A Nowak
1Statistische Abteilung, Universität Bonn, D-53113 Bonn, Germany. limhof@uni-bonn.de
Journal of Theoretical Biology
|May 8, 2007
Summary
Win-stay, lose-shift (WSLS) outperforms tit-for-tat (TFT) in evolutionary game dynamics. WSLS corrects errors and resists invasion by cooperative mutants, unlike TFT, making it a more robust strategy for cooperation.
Area of Science:
- Evolutionary Game Theory
- Behavioral Economics
- Computational Social Science
Background:
- The repeated Prisoner's Dilemma is a fundamental model for studying cooperation.
- Tit-for-tat (TFT) is a well-known strategy but has limitations, including susceptibility to errors and invasion by 'always-cooperate' (ALLC) strategies.
- Win-stay, lose-shift (WSLS) is an alternative strategy that aims to overcome TFT's weaknesses.
Purpose of the Study:
- To compare the evolutionary dynamics of TFT and WSLS strategies in finite populations.
- To investigate the impact of erroneous moves and mutation-selection dynamics on strategy evolution.
- To determine the conditions under which different strategies, including always-defect (ALLD), ALLC, TFT, and WSLS, are selected.
Main Methods:
- Utilizing a novel approach of stochastic evolutionary game dynamics.
- Simulating mutation-selection dynamics in finite populations.
- Comparing the performance of four distinct strategies: ALLD, ALLC, TFT, and WSLS.
Main Results:
- WSLS demonstrates superior robustness compared to TFT, particularly in the presence of errors and cooperative mutants.
- ALLD is selected when the benefit of cooperation is below a critical threshold.
- WSLS is selected when the benefit of cooperation exceeds this critical threshold.
- While TFT is not directly selected, it can lower the threshold for WSLS selection.
Conclusions:
- WSLS is a more evolutionarily stable strategy than TFT in the studied model.
- The benefit of cooperation is a critical factor determining the success of cooperative strategies.
- Error correction and resistance to defection are key attributes for successful strategies in evolutionary dilemmas.
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