1. UUCF Summer RE 2011 Brain Glitches Session 8: Ultimatum Game and The Volunteer’s Dilemma

2. The Ultimatum Game In our last game, Prisoner’s Dilemma, each player faced the same choice, with the same consequences. Today’s game, The Ultimatum Game, will also be a two-player game, but the players will have different roles.

3. Player 1 Player 1 will receive ten “points”. Once again, points will be represented by M&M’s Player 1 will decide how many to keep, and how many to offer to Player 2. As before, this is done without any discussion between the players.

4. Player 2 Player 2 does nothing until Player one has divided the points and shown the offer to Player 2. Player two then makes one decision, without discussing it with Player 1. Either: Accept Player 1’s offer, and both players receive the points as divided. Reject Player 1’s offer, in which case both players receive nothing.

5. Possible variations Play one round and stop. Play a preset number of rounds. Play a number of rounds, but the players will not know in advance how many rounds there will be. Allow the players to talk to each other

6. Let’s Play!

7. What’s going on here? If a computer is playing as player 2, it will accept any non-zero offer, no matter how small, as being better than nothing. People don’t usually do this. Why not? Are you using any kind of a strategy?

8. Volunteer’s Dilemma This is a group game. Everybody plays at once. Each player starts with a cup with 20 M&M’s each. Again your choices are either C or D. As usual, no discussing your choices.

9. Scoring If you pick “C” you score zero. Always. If you pick “D” you score 1 point, AS LONG AS SOMEBODY PICKED “C”. If nobody picked “C”, everybody loses 10 points.

10. Let’s Play!

11. What’s going on here? How are you deciding what to choose? How does this game compare to the Prisoner’s Dilemma and the Ultimatum Game?