Thank you for participating in this study. We expect this study
to last about 90 minutes. Your earnings in this study will be paid to you in
cash at the end of the session.
Throughout the experiment your identity
will be kept totally private. Neither the experimenter nor the other
participants will ever be able to tie you to your decisions.
The Experiment
In this experiment you will play a series of 20
games. In each of the 20 games you will be randomly paired with one other
person for that game. Your partner in each game will change randomly throughout
the study. You will never be able to predict which of the other participants in
the room you are paired with for any game. Also, you will never play
anyone more than one time.
In each game, you and your partner will make
choices in two rounds. When the two rounds are over, your game will be
complete. Then you will be randomly assigned a new partner and start a new game,
again with two rounds.
You will repeat this process until you have
completed a total of 20 games. Since each game will have two rounds, you will be
in a total of 40 rounds over the course of the experiment.
In each game
you will earn tokens. The tokens you earn in each game will be deposited
in your Earnings Account. At the end of the study you will be paid $0.06 for
every chip in your Earnings Account.
Each Round
Each game has two rounds. In each round you will decide
between one of two options. You can either pull an amount X to yourself,
or you can push an amount Y to your partner. In every decision, the
amount you can push is three times the amount you can pull, that is, Y=3X.
However, the values of X and Y will be changing from round to round.
Here
is an example of a decision:
I choose to:
pull 10 tokens to myself, or
push 30 tokens to the other player
My partner chooses
to:
pull 10 tokens to him/herself,
or
push 30 tokens to the other
player
There
are four possible outcomes:
Possible Outcome 1: If you decide to
pull 10 tokens to yourself and your partner decides to push 30 tokens to you,
then your payoff is 40 tokens and your partner's payoff is 0
tokens.
Possible Outcome 2: If you decide to pull 10 tokens to
yourself but instead your partner decides to pull 10 tokens for himself, then
your payoff is 10 tokens and your partner's payoff is 10
tokens.
Possible Outcome 3: If you decide to push 30 tokens to
your partner and your partner decides to push 30 tokens to you, then your payoff
is 30 tokens and your partner's payoff is 30 tokens.
Possible Outcome
4: If you decide to push 30 tokens to your partner but instead your partner
decides to pull 10 tokens to himself, then your payoff is 0 tokens and your
partner's payoff is 40 tokens.
As you can see, your partner will be faced
with the same decision as you. You will both make your decisions at the same
time. That is, you must make your decision without knowing what your partner is
deciding.
Each Game
Each time you are paired with a new partner you will play a
2-round game with that person. In each round you will make a decision like that
above.
Here is an example of what a game could look like:
Round 1
Decision:
Round 1 - Make a Choice
My partner chooses
to:
pull 3 tokens to him/herself,
or
push 9 tokens to the other
player
Round 2 - Next Round
I choose
to:
pull 7 tokens to myself,
or
push 21 tokens to the other
player
My partner chooses
to:
pull 7 tokens to him/herself,
or
push 21 tokens to the other
player
Notice
that when you are asked to make your decision in the first round, you will also
be able to see the decision to be made in the second round. This is shown in the
grayed-out portion of the decision screen.
So, for example, suppose that
in Round 1, you decide to push 9 tokens to your partner and your partner also
decides to push 9 tokens to you. Then your payoff for the round would be 9
tokens and your partner's payoff would also be 9 tokens.
You will be able
to see the results of your decision and your partner's decision before you make
your decision for the second round. The screen you will see for your
second-round decision looks like this:
Round 1 - Results
I choose
to:
pull 3 tokens to myself,
or
push 9 tokens to the other
player
My partner chooses
to:
pull 3 tokens to him/herself,
or
push 9 tokens to the other
player
Round 1 - Earnings
You: 0 + 9 = 9
Your Partner: 0 + 9 = 9
Round 2 - Make A Choice
My partner chooses
to:
pull 7 tokens to him/herself,
or
push 21 tokens to the other
player
After
seeing these results, you can go on to make a choice for Round 2. Suppose in
this Round 2 you chose to push 21 tokens while your partner chose to pull 7.
Then for this decision you will earning nothing while your partner earns 7 + 21
= 28 tokens.
This makes your total earnings for the game 9 + 0 = 9, while
your partner's total earnings are 9 + 28 = 37. The results of this game will be
reported to you like this:
Round 1 - Results
I choose
to:
pull 3 tokens to myself,
or
push 9 tokens to the other
player
My partner chooses
to:
pull 3 tokens to him/herself,
or
push 9 tokens to the other
player
Round 1 - Earnings
You: 0 + 9 = 9
Your Partner: 0 + 9 = 9
Round 2 - Make A Choice
I choose
to:
pull 7 tokens to myself,
or
push 21 tokens to the other
player
My partner chooses
to:
pull 7 tokens to him/herself,
or
push 21 tokens to the other
player
Round 2 - Earnings
You: 0 + 0 = 0
Your Partner: 7 + 21 =
28
That was the end of game
1.
Total Game Earnings
You: 9 tokens
Your Partner: 37
tokens
When you
finish viewing the results of the game, you can click . Then you will be randomly assigned a new
partner from the others in the room and begin a new 2-round game.
How the Amounts to Pull and Push will Change
The amounts available to
pull and push will change from round-to-round and from game-to-game. Here we
explain how these values will be set.
For each decision, the number of
tokens available to push will always be 3 times the number available to pull.
For example, if you can pull 2 then you can push 6. Or, if you can pull 8, then
you can push 24. If you can pull 10 then you can push 30.
In any decision
the tokens you can pull will always be between 0 and 10. Since the push amounts
are three times the pull amounts, the amount you can push will always be between
0 and 30.
There will also be a special way the pull and push amounts are
determined within a game. In particular, the number of tokens you can pull in
Round 1 plus the number you can pull in Round 2 will always equal 10. For
example, if you can pull 4 in Round 1 then you can pull 6 in Round 2. Or, if you
can pull 1 in Round 1 then you can pull 9 in Round 2. If you can pull 10 in
Round 1, then you can pull 0 in Round 2.
Note that since the pull amounts
in Round 1 and Round 2 always sum to 10, this means that the push amounts in the
two rounds will always sum to 30. In other words, all games will have the same
feature that the total amount to pull across the the two rounds is 10 and the
total amount to push is 30. How games will differ is in how many push and pull
tokens are allocated to Round 1 and how many to Round 2.
Finally, the
push and pull amounts you see in any game will be drawn at random from all the
possible pull and push amounts that meet these rules above. You will never know
what values you will see in future games, but all possible values are equally
likely.
So there are three things to remember about how the pull and push
amounts are set:
The push amounts are always 3 times the pull amounts.
In each game the pull amount in Round 1 and the pull amount in Round 2
always sume to 10. As a result, the push amount in Round 1 and the push amount
in Round 2 sum to 30.
The values in each game are determined at random from all the values that
meet rules (1) and (2)
Your History
If you want to look back at the history of play you have
seen over the experiment, you can do this from any screen by hitting the button . This will show you your decisions,
your partner's decision, and your earnings in each game.
Overview of the Experiment
As we are about to begin, keep these things
in mind:
You will play a total of 20 2-round games.
For each 2-round game, you will play with the same partner for both of the
rounds.
When you start a new game, you will get a new partner, chosen at random
from everyone here today.
You will never play the same person more than once.
In each 2-round game the total amount to pull across the two rounds is 10
and the total amount to push is 30. The games will differ in how much of this
is allocated to Round 1 and how much to Round 2.
You will be paid your total earnings across all 20 of the 2-round games.