Cognition Laboratory Experiments

John H. Krantz, Hanover College,






Mental Imagery


Decision Making


Statistical Concepts

Hanover College
Psychology Department

Instructions for the
Prisoner's Dilemma Experiment


When you click on the link below, you will be presented with the experiment setup screen.  On this screen will be the variables you can set to define your condition.  Here is a list of the variables and their settings.  Not all variables will be visible all the time.  Only those variables appropriate to the stimulus and other settings will be shown.  So changing some values may alter what is shown on the setup screen.

Variable Settings
Type of Prisoner's Dilemma The scenario you can use.  Current: Traditional and Evil Priate
Number of Trials Number of times the scenario will be repeated.
Pattern of Computer Responses The way the computer will respond to the users choices.  Current only random and experimenter input (Entered Pattern) are implements.  In entered pattern a button will appear to allow the experimenter to determine if the computer will defect (compete) or stay silent (cooperate) for each trial.
Delay between trials How long of a break is there between two trials.  From .25 to 2 seconds.

After you have finished making your settings, press the Done button at the bottom of the screen.  The Prisoner's Dilemma experiment screen will then be presented. 

Instructions will be presented describing the scenario.  At the bottom half of the screen the outcomes will be summarized.  Pressing the start button will begin the experiment.  When started, button will appear to allow the participant to respond.  A summary table will appear tracking their last responses and outcomes and the computers and the current total outcome.

At the end of the experiment, your results will be presented.  You can also get your trial by trial results.  In the response part of the trial results, a null indicates that no selection was made.  Closing your results window(s) will take you back to the setup window so you can run another experiment.

Click here to start the experiment.