There are two steps in this game. Below we first describe the second step so that you know what decisions you will be making and how your earnings will be determined, and then we describe the first step in which you can send a message to your counterpart.

Second Step

In the second step, you and your randomly matched counterpart will separately and independently choose a shape. Both of you have two shapes to choose from: Square or Triangle.

There are four possible situations:

• If both of you choose Square, then both of you will earn 100 points.

• If both of you choose Triangle, then both of you will earn 50 points.

• If you choose Triangle while your counterpart chooses Square, then you get 90 points and your counterpart gets 20 points.

• If you choose Square while your counterpart chooses Triangle, then you get 20 points and your counterpart gets 90 points.

First Step

In the first step, you and your counterpart will separately and independently select a message to send.

The message is in the following format: “You should choose_______.” You can select one of shapes to fill in the blank line.

Please note that your counterpart doesn't have to choose according to what you say in the message. Similarly, you don't have to choose according to what your counterpart says in his or her message.

Your Role in this Game

While both you and your counterpart are asked to select a message, only one person will be randomly selected as Message Sender, and the other person will be selected as Message Receiver.

After you have selected your message, you will first be asked what you will choose in the second stage if you are the Message Sender. This is the case where only your message is delivered. This means that you don't receive the message from your counterpart, but your message is sent to your counterpart.

Then you will be asked to make two guesses about your counterpart's choices.

Next you will be shown your counterpart's message and will be asked what you will choose in the second stage if you are the Message Receiver. This is the case where only your counterpart's message is delivered. This means that you can receive the message from your counterpart, but your message is not delivered.

Then you will be asked to make two guesses about your counterpart's choices.

Your role of message sender or receiver varies across the games. You will not know your role in each game until the end of the experiment. It is in your best interest to treat each role (message sender or receiver) as if it is the one that determines your payoff.