Sample 1 – Sample1.exp (text from Tutorial on the MediaLab Help menu)

"So I've installed MediaLab. Now what do I do?" Good question. This brief tutorial (about 15 minutes) will walk you through the basics of MediaLab. After you've run through this short tutorial you will likely be able to design and execute a short experiment of your own. This on-line tutorial can be run at any time by clicking Help > On-line Tutorial from the main menu. You might find it helpful to print out this tutorial so you will be unobstructed as you go through the steps of running and editing the sample experiment.

This purpose of this short tutorial is to give you the gist of how MediaLab works. After running through it, you may wish to check out the additional sample experiments and questionnaires located in the Samples folder of the MediaLab program folder (usually C:\MediaLab\Samples). For more detailed help, select Help > MediaLab Help from the main menu of MediaLab or press F1 at any time. You will also find a printable PDF manual located in the Help folder (usually C:\MediaLab\Help) called MediaLabManual.pdf.

Step 1: Run the Sample Experiment

The first sample experiment is as simple as MediaLab gets—a basic questionnaire, in this case measuring self-esteem. To run Sample1.exp:

1.First, if MediaLab is not running full-screen, then make it so by clicking the maximize button in the top-right corner of the main MediaLab window (it's the one in the middle).

2.Go to the Run command in MediaLab and choose Select and Run Experiment.

3.Find the Samples folder located in the C:\MediaLab directory.

4.Double-click on the Sample1 folder, and then double-click on Sample1.exp. Note that experiment files are indicated by a green "building block" icon and that questionnaire files are indicated by a "paper and quill" icon.

5.Enter a Subject ID (e.g., 5), and press Enter.

6.Enter a 1 for the experimental Condition, and press Enter.

7.Follow the instructions as if you were a participant.

Step 2: See How it Was Done

From the main menu in MediaLab select Experiment Editor.

When the Experiment Editor opens, select Open from the File Menu and open Sample1.exp.

You'll see that there are 2 conditions. Everybody in condition 1 gets only one file—selfesteem.que.

However, in condition 2 you see that these subjects will also get a PowerPoint Show (.pps) file before they get the self-esteem questionnaire. In MediaLab experiments, you can define as many conditions as you like, with each having as many files as you like. These files can be the same ones in different orders, or they can be different files altogether.

That's all there is to this experiment.

Close the experiment file by clicking OK. Then close the Experiment Editor. This will return you to the main MediaLab window. Now run the experiment, enter a subject ID, but ask for Condition 2 this time. After that...

Step 3: See How the Questionnaire Was Made

From the main menu bar in MediaLab select Experiment Editor.

When the Experiment Editor opens, select Open from the File Menu and open selfesteem.que.

Here you'll see the items contained in the questionnaire file. Here you can see the basic information about each item—the ordinal position, the item name and the question wording or filename. Double-click on any position number to see the item details. Note how Scale Responses require the p parameter telling MediaLab how many scale points the question requires. Try using the context sensitive help here. Place the cursor on any field (e.g., the position field) and pressing F1. Close the Details window by clicking on the big checkmark in the lower right corner, and then click OK to close the questionnaire and then close the Experiment Editor.

Step 4: Look at the Data

Your data will be located in a data folder contained in the same directory as your experiment. From the Data menu in MediaLab, select Launch Explorer. Find the Sample1 folder and open the Data folder located inside. In here, you will see two folders. Usually, you will use the byvariablename data folder. Take a look inside and you'll see a number of files. MediaLab has generated all of these files for you automatically. The first one to look at is sample1.csv. You can open this with Excel. Try it. (note that all the variables that start with t are response times).

If you've got SPSS installed, you can open sample1.sav. Or you can open the .sps syntax file, highlight everything in the file and run it. This input file tells SPSS to read the data file sample1.txt (also located in your data folder), and defines all of the variables. After running this input file in SPSS, you can analyze it right away. Try doing some frequencies or means.

The other file in the main data folder is called comment.txt. You can open this in any text editor. This file contains the open-ended responses from the essay item called comment in the self-esteem questionnaire. MediaLab writes the data from essay questions to their own file since it would get out of hand to write these to a standard data file.

Step 5: Modify and Run the Experiment:

Now let's try to modify the experiment you just ran. With Windows Explorer still open, make a copy of the selfesteem.que questionnaire file and rename it myquestionnaire.que. Then, double-click on it to open it in the Experiment Editor.

This is where you can have some fun. Try changing the question wordings. Double click on any position number to see the details for any item. Try this with a Scale Response item. See where it says (p6) in the parameters field? Try changing this to (p9). See how you now get 9 response options for the questions? You can add the additional options in the Label and Text Label fields.

Close the Details window by clicking on the big checkmark in the lower right. Try adding an item of your own. In the first open position, enter a new position number of 4.5. Enter an item name such as MyVar. Double-click on the ItemType field and choose Fill-in-the-blank from the pull-down menu. Finally, enter your question wording in the Question Wording/File Name field, e.g., "Please tell me what your favourite food is."

Now click Sort and then Renumber. See how the item is now positioned between the 4th and 5th items? This happened because you gave the question a position value of 4.5.

Now click Save and OK to close the questionnaire.

Now we need to add your new questionnaire to the experiment file. From the File menu select Open and open the Sample1.exp experiment file.

Let's replace the selfesteem questionnaire in Condition 1 with your new questionnaire. Simply double-click on selfesteem.que in Condition 1, Position 1. When the dialog box opens, select you new questionnaire. See how it has replaced the old questionnaire?

Let's add another file to Condition 1 in addition to your questionnaire. In the first available row of your experiment file and enter a value of 1 in the Condition field. Enter a value of 2 in the Position field. Double-click on the File Name field and select an image file on your hard drive (and jpg, bmp or gif file). To see the types of files you can add here, click Files of Type when the dialog box opens. If you have Internet Explorer 4 or later installed, you could also enter a web address (e.g., here or a local HTML file. After selecting a file, click Sort, then Save and OK.

That's it. Close the Editor and return to the main MediaLab window. Choose Select and Run Experiment and run Sample1, Condition 1 again. Note that if you have made changes that will affect your data files, you'll want to click the Clear Data button to delete the old data files and start fresh (after backing them up if there are data you want to save).

That's the gist of MediaLab. Of course experiments can get much more elaborate than this but the basic idea is always the same. The experiment file defines the files that will be presented in each condition. These files can be pretty much anything including MediaLab Questionnaire files which allow you to ask questions. For more detailed help, be sure to check out the manual (MediaLabManual.pdf) contained in the MediaLab Help folder and to use the OnLine Help by pressing F1 at any time. More samples are contained in the Samples folder.

Sample 2 - Scale Responses and an Introduction to Parameters

C:\MediaLab\Samples\ (requires unzipping)

This sample demonstrates what you can do with scale responses. It starts with the most basic application and ends with a relatively advanced example. You will need Microsoft's Internet Explorer, Version 4 or later installed to view the HTML files that are used in this sample. Click Continue or press the spacebar to begin. Press Ctrl+Alt+Right to exit the sample at any time.

Standard Scale Item

The first scale response you'll see is the standard format which uses just the point (p) parameter to indicate the number of scale points (see the Parameters field). This tells MediaLab how many scale points you want. In this case, it's 6. Click Continue or press the space bar to see the item. When the item appears, you can click Go Back to see this screen again or enter a response to continue.

Inserting Prior Responses in Question Wording and Skipping

With scale items and fill-in-the-blank items, you can enter subject's responses in later question wordings. For example, what was the response you just gave to the last question? Whatever it was, it should show up in the next item. The question wording specifies <rse9>. That tells MediaLab to insert the subject's response to the item with variable name "rse9" into the question wording of this item.

Also notice that we're using "skip to" values here. The values in the Skip To field allow you to skip a subject to any subsequent questionnaire item by entering the item name in the Skip To field. Below, you can see the Details for the next three questions: rse10, rse11 and rse12 (you may have to scroll down). To illustrate, say we want people who disagree with rse10 to answer question rse11 and we want those who agree to rse10 to answer question rse12. To do this we enter "rse12" in the Skip To field of the agree responses in rse10. If the participant agrees to rse10, they will be skipped to rse12, otherwise they will continue on to question rse11. Scroll down here to see the details of rse11. See how the participant is unconditionally skipped to rse13? This ensures that they will not get rse12 which was designed for those agreed to rse10. If that's confusing try going back and forth using the Go Back button trying the different combinations to see how it works. You'll see that depending on what you answer to rse10, you will get only rse11 OR rse12. Instead of a single item, you could also have entire blocks of items designed for a particular response.

Multiple Response Item

Sometimes you may want a participant to be able to check more than one response. That is when you can use the multiple response item instead of the scale item. It works exactly like a scale response except that MediaLab will allow multiple buttons to be "checked". In this example, try clicking multiple answers. When you're done, click Continue or press the space bar. Multiple response items use all the same parameters as Scale Items. Note that on this item we turn off the QuickStyle we applied earlier using the ($off) parameter. You should see that MediaLab reverts to the default colors and fonts.

Inserting HTML in Place of Question Wording and/or Response Labels

Want more control over formatting? You can create an HTML file and display it in place of the usual question wording and even the text labels on the response buttons. In the experiment folder, there is a subfolder called "sp". This folder contains the HTML files and media. In the Background field, see that we specify that we want MediaLab to display "sp/rse.htm" --an HTML file in the SP folder. When we do this we have to specify the area for it to cover using the top and left as well as the width and height parameters. We are also going to display html files in place of the response labels. To do this, we enter the name of the HTML files in place of the usual Text Labels. To allow for more space to accommodate the larger HTML labels, we have triple spaced the buttons using the spacing parameter (s3). We have also specified that the scale buttons be moved over to the right and upwards using the Left and Top parameters. Finally, since the HTML files have a white background, we have applied a QuickStyle file (white.mlq) here that instructs MediaLab to use a white background. This way the HTML files will blend in.

End of Scale Item Sample

That's it. This sample represent much of what you can do with Scale Items. Of course, everything you've seen here is optional aside from the use of the Points (p) parameter telling MediaLab how many scale points you need (e.g., as in the first question, "rse1"). Hopefully, if you need more options than that, you've seen here how to accomplish what you need. If you have any questions, feel free to contact us at

Adding Response Options & Modifying Button Labels

The next item is pretty much the same except that we've changed the Points (p) parameter to 9, providing for 9 response options. We've also changed the button labels to include negative values. Since there are no "negative" keys on the keyboard, you would need to label your keyboard appropriately (e.g., with 1 or F1 corresponding to -4, 2 or F2 as -3 and so on). Click Continue, or press the space bar to see the item.

Horizontal Response Scale

The next scale item is the same as the first except we now add the width parameter. This tells MediaLab we want a horizontal scale and specifies that it should be 500 units wide. See "Show Location Points" in the Help menu for the sizing scale that is used with your display. MediaLab tries its best to use a resolution-independent display. Click Continue, or press the space bar to see the item.

More Room for Question Wording

The next item again is the same as the first, except now we add the top parameter which tells MediaLab that you want the buttons to start at a specific distance from the top. With this, you can move the buttons up or down as much as you like. Note that you can use the top and width parameters together to create a horizontal scale at a specified height. Click Continue, or press the space bar to see the item.

Getting Subjects' Attention

Sometimes after answering many questions, the items can start to "blend in" with one another. A couple things you can do to minimize this: You can add an onset parameter which delays the display of the question wording. In this case we've added (o1000) which means there will be an approximate 1000ms delay before the question wording appears. We've also added a QuickStyle parameter. QuickStyle files can be created in the MediaLab preferences menu. They contain font and color information. In this case, we apply a style file called "green.mlp" located in the experiment folder by entering the parameter value of ($green).

Creating More Room For Response Labels

In this item, we have some very long response labels. To create more space for them, we can double, triple or even quadruple the spacing of the buttons using the spacing parameter. In this case, we've entered (s2) to double space the buttons. Any value-decimals included-between 1 and 5 is acceptable.

Turning off the QuickStyle and Imposing a Time Limit

When this item occurs, we shut the previous QuickStyle off by entering a QuickStyle parameter of ($off). An alternative would be to apply a different QuickStyle file. Using the ($off) value returns the colours and fonts to the default settings in your preferences file. We also add the duration parameter here to impose a time limit on the question. In this case, you will have up to 5 seconds to respond. Try letting the time pass and see what happens.

Adding Other Media

It's easy to add sound, images and video to your questionnaire items using the "Back" fields. In this case, we add an image in the Background field and a sound file in the Backsound field. In this case, we have entered parameters for the Background image immediately after the filename (this is always optional). This will locate the image with a left value of 300 and a top value of 100.

Adding a "Specify" Response

In some case you may want to offer an "Other" response. If you add <specify> to any response label, then MediaLab will prompt subjects to specify their answer if they choose this button. Try it. When the item appears, select the "Other" response and see what happens. If a subject specifies an answer like this, then the text response is written to the data file instead of the button they pressed.

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