Condition (Experiment File)


Identifies which files are presented together in an experimental session.


You may use alphanumeric characters. Usually numbers are used, but words are also allowed in this field. For more than 9 conditions, you can label the first 9 conditions using two digits (e.g., 01, 02, 03 etc.) to preserve numeric/alphabetic consistency.


When you run a MediaLab session, you will be asked for two things: 1) a Subject ID for writing to the data file, and 2) the Condition you want to run. MediaLab will then read your experiment file and look for all the files that belong to the condition you specify. Therefore, in the experiment editor you need to identify which conditions receive which files.

In your experiment file, you can create as many conditions as you like. Simply create a unique identifier for each. You can use numbers (1, 2, 3, and so forth) or text (cond1, male speaker, sg24, and so forth) to identify your conditions. Just be sure to give the same condition id to every file that you want to be presented in that condition. If a file is to be presented in multiple or all conditions simply list it once with each condition id.


Values are treated as words for purposes of sorting. So if you have more than nine conditions and are using numbers to label the conditions you may want to use two digits (e.g.,  "01", "02" … "09", "10" etc.) to maintain your numerical order after sorting.

Using long text identifiers can be a pain when you are running many subjects and have to type the long condition names to start the experiment every time. Using numbers or short letter combinations to identify your conditions will solve this.

For factorial designs, try assigning single letters to represent the various levels of your factors. For example, imagine a persuasion experiment with a 2 (attractive vs. unattractive speaker) x 3 (strong vs. weak vs. no arguments) design. The two levels of the speaker factor could be represented with A and U, and the three levels of the argument factor could be represented with S, W, and N, respectively. The six conditions might be identified as AS, AW, AN, US, UW, and UN. Or for simplicity, you might simply label them 1, 2, 3, 4, 5, and 6 while keeping a record of which number corresponded to which experimental condition.