Darwin’s theory of evolution is explicitly competitive, yet co-operation between individuals is a common
phenomenon. The Prisoner’s Dilemma model is central to the teaching of the evolution of co-operation.
The best-known explorations of the Prisoner’s Dilemma are the tournaments run by Robert
Axelrod in the 1980s. Aimed at students of biological or behavioural science (post-compulsory education),
this paper proposes a simplified, non-computer-based version of Axelrod’s Tournament which
allows students to explore the Prisoner’s Dilemma using different behavioural strategies. In this classroom
exercise, students become the players in a repeated Prisoner’s Dilemma situation. They investigate
the outcomes of different strategies of play using a simple scoring system. After each generation of play,
students discuss the evolutionary success of the strategies–strategies that score poorly are discarded and
replaced with those that score well. Four generations of play are suggested, after which ‘Tit for Tat’ will
have become the dominant strategy in the population, as it did during Axelrod’s original tournaments.
Students gain a basic understanding of the evolution of co-operation, and the associated written report
encourages them to investigate the process in more depth.

• Teaching the Repeated Prisoner’s Dilemma With a Non-computerised Adaptation of Axelrod’s Tournament

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