I.                   USING THE DESIGN WINDOW

 

The program window is your workspace. Take a moment to familiarize yourself with the window, its menus, and the toolbars (shown below). The toolbars are identical in function to many of the menu commands. Briefly point the mouse at each button to display a tooltip identifying the button and its function. More specific functions related to this program are presented under Entering and Editing design icons.

 

 

 

 

Drag and drop icons from the list of icons on the left to create a game.

 

Designing games, extensive form games, matrices, combination of different
 

 

 

  1. The basic Icons needed to design an auction

 

 

 

 

 

 

 

  1. Necessary icons

 

  1.  
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Entering and Editing Design Icons

 

 

II.                BARGAINING GAME

 

  1. Designing one period Ultimatum game

 

1. Adding

 

a.                  Drag and drop Two  icons into a design window.

b.                  Click on the  to select it.

c.                  Double click on  to rename it to .

d.                  Open the  window by double clicking on the edge of the icon or click on to edit the condition. By default the window is empty:

 

e.                  The condition has to be a Boolean type (i.e. true or false).

 

a.                  Double click into   and right mouse click  to access Function editor .

 

 

·               Write the condition directly or with the help of Assistant editor.

·                Condition: subject_number()%2=0 means that remainder is zero (i.e. a subject with an even number is assigned a ). A subject is assigned a consecutive number after login to the game. The first player to login is assigned number 0, the second player to login is assigned number 1.

 

·                Select Assignment 2 as a next assignment (i.e. if subject_number()%2=0 is false then check Assignment2)

 

 

 

 

·                    The result is the link between  and :

·                     Double click on  and change the name to

·                    Condition for  is empty. It means that everybody who does not have an even number is a responder.

·                     The program checks the condition from a starting assignment which is determined with a lighter green color. By default the first assignment created has a lighter color. If you delete that assignment or you want to start from another assignment select that player and then click on .

 

2. Adding  

 

a.                   Create as follows:

·                                            Drag and drop a  into a design window.

·                                            Rename it to .

·                                            Open by selecting and double clicking on the edge of the icon or just clicking on .

 

·                                             Select

 

·                                            Type lower and upper bound for the offers:

 editor should have:

b.                 Create as follows:

·                                             Drag and drop a  into a design window.

·                                             Rename it to .

·                                             Open .

·                                             Select

·                                             For  and click return to verify if the statement is correct. If yes, the red rectangle disappears.

·                                             Write the default values for the :

·                                             Select . It means that a subject has to select one of the two columns (i.e. Accept or Reject by clicking on a cell). Subject will see  as:   and once she selects an option it will be highlighted:

 editor should have:

 

 

 

 

2. Necessary  added.

 

a.             Create  as follows:

·                                            Drag and drop a  and rename it to

·                                            Open  by double clicking on the edge of the icon or by selecting  and clicking on .

·                                             Select 

Note: In order to show the choice: to the responder or in the results, variable   has to be created. and updated with.

 

b.             Create  as follow:

·                     Drag and drop a  and rename it to .

·                     Open .

·                     Change

Note: In order to show the choice:  to the responder or in the results, variable  has to be created.  and updated with.

 

 

c.                  Create  and  to present the earnings at the end of the game. See “Update Variables with ” for the calculations.

·                     Select  

 

d. Create  to show the  the potential earnings if the offer is accepted. See “Update Variables with ” for the calculation.

·                     Select  

 

 

 

 

  1.  added to enhance the presentation of results

a. Create to collect the ID number for each subject.

·                      Change

·                      Select to create a subject specific variable.

 

b. Create  variable to show the data in a tabular form.

·                    Change  given that the data would be a mix of text and real numbers. See “Update Variables with ” for the calculation.

 

·                     Change   , the first row for a proposer, the second row for a responder.

·                      Change  

·                     Labels the columns:

·                    Label the rows:

 

 

d.            Create  to collect all the data for all sessions participating in the experiment by copying .

·                     Select .

 

·                    This data will only appear in the summary stage if it is inserted there:  This stage is selected by clicking on . The font color is light green.

 

·                should not be selected in the design window.

 

 

2.            Add  and

a.       Create stage

 

·                                             Open

·                                             Write instructions

·                                             To insert the image, select

·                                             Select . If  is selected subjects see all variable’s values and they have the control when to continue to the next stage.

b.                 Create  that follows .

·                     Select , drag and drop  design window. The following link is established.

·                     The alternative way to connect and  is to click on the blue rectangle in the middle of and drag the mouse to .

 

 

 

 

 

 

c.                  Create  stage

 

·                     Open  stage

·                     Write a text

·                    Insert an image

·                    Insert by clicking on Insert and selecting “offer to the responder”.

 

·                    The other option to Insert is to right click on the background and select “offer to the responder”.

 

·                     Select

means that a proposer makes a decision.

means that responder will see exactly the same page as a proposer. However she will not be able to make any decisions.

 

 

d.                  Create  that follows .

 

 

e.                  Create stage

  • Write the text
  • Insert variable
  • Insert choice: “Response”
  • Insert variable: “Offer to responder”
  • Insert variable: “Proposer potential earnings”
  • Select:

 

 

f.                    Create  that follows  .

 

5. Update Stage  and  in

Update Stage

Update   in

a. Update :

·                       Open  window.

·                       Select stage transition: Proposal by clicking on the arrow next to Stage transition or right click mouse on the background. 

Proposer editor is created:

Leave Proposal editor empty. It means that with probability 1  stage will be selected.

 

The following link is created:

 

 

 

b. Update :

·                       Open  window.

 

·                       Select stage transition: Responder by clicking on the arrow next to Stage transition or right click mouse on the background. 

 

Responder editor is created:

Leave Responder editor empty. It means that with probability 1  stage will be selected.

 

The following link is created:

 

 

a.                 Update variable

·                                            Open  window:

 

·                                            Select variable  by clicking on the effort next to Variable update or right click on the background under the variable update:

 

·                                            Write the choice: offer to the responder in the editor. To color the choice, select “offer to the responder” and click on “Ctrl+Shift+c” or use Function editor by right mouse click inside the offer to responder editor. 

This variable save the choice for presenting Responder with the decision that the proposer made.

 

 

 

b.                  Update variable

·                                            Open  window:

·                                            Select variable

·                     Write the following expression in the  editor:

Note 10 was the maximum possible offer to the responder.

 

 

 

 

Update Stage

Update   in

c.                  No update for  between:

Note that stage follows the stage. When the  stage is selected by clicking on  the transition is not necessary.

 

 

 

 

 

d.                 Update variable

·                                            Open  window:

·                                            Select variable  

 

·                                            Write the expression

Response is either Accept or Reject. Subject will see the following: once it is inserted into a stage.

 

 

e.                  Update variable

 

·                     Write the expression in the  inserted  editor:

 

which means if the choice Response is accepted, then the proposer will receive 10 – offer to the responder (i.e. proposer potential earnings). If the offer is rejected, then the proposer will earn 0.

·                    Select  next to the proper earnings editor.   means that the expression is calculated and can be used in the next expression on the same transition.

f.                   Update variable

·                    Write the expression in the inserted  editor.

Select  next to the responder earnings editor.

g.  Update variable .

·                    Write the function subject_id() that can be used to identify each subject. Right mouse click  brings the Function editor where all the functions are listed.

 

h.  Update variable

·                    Write the expression in the inserted  editor:

 

 is 2 by 3 matrix. The update includes Player ID which was originally set as a multiple variable. When it is inserted into a variable that is not multiple it represents a column vector. Comma between variables represents a column, semicolon represent a raw. Variables inside a bracket represent a column vector: [offer to responder; Response].

 

 

i.                     Update variable

·                 Write the expression in the inserted editor.

 differs from  only in the selection of  in the definition of the  variable.

In the stage the data will be presented not only for a particular session that a subject is involved but for all sessions in the experiment.

 

 

Right click on the One Period Ultimatum game to download and use it

 with the Comlabgames program.

 

 

  1. Changes in designing infinite horizon random assignment bargaining game

 

1. Additional  added

a. Create variableto count the number of rounds played in this game.

 

·                     Set initial value to 1:

 

·                     The  will be updated in the transition.

c.                 Create variable  with the following characteristics:

 

Note: no initial value is set. The update of the variable is done in  because each time a game continues a new draw has to set.

 

d.                Create variable  

·                    Set initial value to 0.6.

 

It is a variable that is convenient to create. If you want to change the probability to continue, change the initial value. The change will be updated on all the places where  appears.

 

·                     For example it is used in the instructions:

·                     It is used in the formulae in the  that determine if the game continues. 

e. All other variables:  and  are created in the same way as  and .

 

2. Add or update  and

a. Create a stage  that follows stage:

.

 is introduced to determine who is a proposer, and if the game continues it allows to randomly determine who the proposer is in each repetition of a game.

·                     If you open  neither Proposer or responder sees anything or do anything in this stage which is determined with:

“Passive” is a default selection in the program. It also means that  is used just as a calculation stage.

b.Create that follows : with the following properties:

·                     Insert the stages:  and  in the stage transition update.

·                     Write the probabilities by which the assignment of a proposer is determined. In our case the probabilities are 0.5 for selecting the  stage and 0.5 for selecting  stage.

In the  this condition is represented in the following way:

 

 

 

Updates in   

Updates in  that follow the stage

c. Create  stage:

·                Open   stage.

·                Write the text to reflect random assignment and the probability to continue the game (see the window below).

·                 Insert the choice:  and  at the appropriate places (see below)

·                Insert variable  into the text

·                 Select “Active” for Proposer given that she makes an offer.

·                Select “Observe” for Responder. She will just see the exactly what Proposers sees but will not be able to make any decisions. It is up to the moderator to decide what Responder sees while waiting for the Proposer to make a move.

 

e.                    Create   after  stage.

·                    Open

·                    Insert  stage into a Stage transition.

·                    Leave the expression empty. It means that  stage will be selected with probability 1.

 

e.                 In the  window select the variables to be updated. by clicking on the arrow next to

·                    Update the variable  which is the outcome of the choice: the proposer made.

·                    Update the variable :

·                    Update the variable  

Uniform(0,1) means that a outcome of a random draw from the uniform distribution with minimum 0 and maximum 1 will be recorded in the variable . Whenever a game returns to this stage a new draw will replace the previous outcome in the variable  . 

 

 

Updates in   

Updates in  that follow the stage

f. Create

·                Open   stage.

·                Write the text appropriate text.

·                Insert  so t

·                 Insert the choice:  and  at the appropriate places (see below)

·                Insert variable  into the text

 

 

 

Right click on the Infinite horizon random assignment bargaining game to download and use it

 with the Comlabgames program.