Learning Objectives
- To understand the evolutionary basis of prosocial behaviours.
- To understand evolutionary explanations for self-interest and altruism among related and unrelated individuals.
- To experience variations of the Prisoner’s Dilemma and discuss how they may encourage or discourage different responses.
Materials
- Two decks of playing cards with matching card backs.
- One red-suit and one black-suit card for each student.
- Paper or another way for students to keep track of their scores.
- Candy or another small reward is optional.
Overview
These games model different motivators for prosocial and antisocial behaviour. Students play both one-off and repeated versions of a split-or-steal game, then examine how the structure of the interaction affected their own decisions.
Payouts
The black card represents “cooperate,” while the red card represents “defect.” Players gain points according to the following payouts.
| Player A | Player B | A receives | B receives |
|---|---|---|---|
| Cooperate | Cooperate | 2 points | 2 points |
| Defect | Cooperate | 3 points | 0 points |
| Cooperate | Defect | 0 points | 3 points |
| Defect | Defect | 1 point | 1 point |
Single game
Each student receives a red and a black card. They play three rounds, each with a different person, and keep track of the points they earn.
Half of the class can remain seated while the other half moves to a different table for each round. Coordinate the timing so that everyone places their card face down and reveals it at the same time.
Repeated game
Students move once more and sit across from a fourth person. They then play five consecutive rounds with this same person, keeping track of their scores across the interaction.
Debrief & discussion questions
- What strategies did you use? Were they successful?
- Did your tendency to cooperate change when you knew which round would be the last? Why or why not?
- What other factors might increase or decrease cooperation?
- How could you manipulate the point payouts to increase or decrease cooperation?
- What real-life situations exemplify the Prisoner’s Dilemma?
Expected outcomes
People are usually more prone to cooperation in repeated games because they will interact with the same person again. In the final round, players may become more likely to defect once the prospect of another interaction disappears.