Frequently Asked Questions

This page addresses some common technical questions that you may have when trying to use OPL. If your question is not addressed here or if you need further assistance, please contact the OPL Editor at

Technical Issues

Many of the studies on OPL require a plug-in for your browser in order for the study to be viewed properly. This is because the studies on OPL are apart of a multi-developer effort.

If you cannot see the study in your browser, be sure that you have downloaded the correct plugin for your browser. For Flash, Authorware, or Shockwave studies, get the plug-in here. (Look for your operating system and browser and click the link to download the plug-in. You must get a separate plug-in for each browser that you use.) For Java studies, get the plug-in here.

If you have installed the correct plug-in for your browser and you are still having difficulty viewing the study, you may need to reinstall the plug-in. Please also keep in mind that slower connections (such as basic dial-up connections) may take longer to load and run the various studies on OPL.

Vista Users.Microsoft Windows Vista with Internet Explorer 7 employs an additional security feature called Protected Mode. Protected Mode restricts access to certain files, folders and registry settings on the workstation. Protected Mode is enabled by default for sites in the "Internet" zone. Users have two options when encountering these errors.

  1. Disable Protected Mode
  2. Add appropriate URLs to the "Trusted Sites" zone

Plug-ins are typically third-party software that adds a feature or functionality to an existing application. Plug-ins are quite common for Internet sites because so many browsers are available and all browsers are not created equal. Therefore, you must get a separate plug-in for each browser that you use. Some other examples of plug-ins are Real Player and Quicktime.

Plug-ins may be required for OPL studies because the application in which a study is developed is, for the most part, left to the discretion of the developer. Because OPL supports many different formats, few users will have all of the necessary plug-ins prior to using OPL. We have tried to make the process of obtaining the necessary plug-in(s) as painless as possible and we regret any inconvenience it may cause. However, in order to support a variety of studies and to allow OPL to be a multi-developer effort, plug-ins are a necessary inconvenience.

When installing the required plug-in for a study, you must enable your pop-up blocker if there is one installed. Internet Explorer may block the plug-in install automatically and put a small yellow bar at the top of the browser (See example) to indicate that the plug-in was blocked from running. This may occur if you have not downloaded and installed the plug-in. And it may occur even after installation. Disabling the pop-up blocker and/or turning on the right security settings to allow the study to run will vary according to your browser. For Internet Explorer and Firefox users, see our example here. For all other browsers, you must follow your browser's documentation on enabling Active-X components to run within your browser.

OPL is best viewed with Internet Explorer 6+, Mozilla Firefox 1.0+, Safari 1.3+, or Netscape Navigator 7.2+.

OPL is best viewed at a screen resolution of 800x600 or higher. If you are unable to see the entire site without a horizontal scrollbar or it is not viewable at all, you may need to set your screen resolution to 800x600 or higher.

Class Information

A Class ID is a number associated with each class registered on OPL. It is not the same as the User ID that you receive when you participate in an experiment. (You can look up your Class ID here.) By registering their classes, educators can view data submitted by their class. (They have the option of viewing data from multiple classes also.) A Class ID also allows for the class data to be tracked and stored in an easily retrievable manner. Educators are not required to register their classes, but it will be more difficult to find data from their students specifically.

Students will find a Class ID useful if they are participating in a study for a particular class. When asked for a Class ID, they can enter the number or they can scroll through the (long) list of classes to find the one that they are looking for. Thus, a Class ID will make locating a class easier and faster.

Some persons who access OPL are not participating in any particular class and are simply "Other Interested Persons". The page that asks for a Class ID has a link called "If you are not a student, click here." If you are not a student of a class, you may click this link and your data will be stored under the "Other Interested Person" category. Then, if you wish to download your data, you would enter 1 for Class ID on the data download page.

You can look up your Class ID here.

A User ID is a number used to identify individual participants in OPL studies. Every person who participates in a study and saves his/her data will be assigned a User ID. This User ID will be displayed on the confirmation page that signifies that the data were successfully saved. (You should see a red checkmark and a big, bold number.) This User ID will be used to identify the participant and is linked to his/her class, if applicable. Students may need to supply this number to their teachers as proof that they have participated.

No personal identification information is stored about participants with the exception of subject variable data such as gender, age, and musical training. Names and addresses are not collected.

No. You must enter your Class ID in order to retrieve data. You can look up your Class ID here. If you participated in an experiment as an "Interested Person", enter the number 1 in the Class ID box on the data download page.

Content Issues

Timing is excellent both for on-screen displays (i.e., tachistoscopic presentations) and for reaction time measurements. Indirect evidence of accuracy can be found at:

All studies submitted must be evaluated for scientific accuracy, psychological principles, and other qualities before being accepted for incorporation into OPL. If you are interested, please contact the Advisory Board at

Downloading Data

Many statistics programs provide a wizard to help you import data. A CSV file downloaded from OPL should require minimal user interaction to import into your statistics program. However, the CSV files on OPL have the variable names at the top of the file. You may have to indicate this to your statistics program in order for the file to import properly. For a brief tutorial on how to import a CSV file into SPSS, click here.

OPL is optimized for Microsoft Excel 2003 and newer. Microsoft Excel requires the Analysis Toolpak to perform data analyses such as correlation, covariance, and descriptive statistics. For instructions on how to get the Analysis Toolpak, go to Microsoft's documentation found here.

If possible, we highly recommend that you upgrade to the latest version of Excel in order to fully take advantage of the functionality on OPL. However, if you have a version of Excel that is older than 2002, you will have to follow special instructions when downloading and importing data from OPL. Follow our tutuorial here.