Creating Instructions

Next, let's define the instruction pages. First, we'll create an introduction page:

<page intro1>  
The tasks that you will be doing in this experiment involve CATEGORY JUDGMENT. 
On each trial, a stimulus will be displayed, and you must assign it to one of 
two categories. You should respond AS RAPIDLY AS POSSIBLE in categorizing each stimulus, 
but don't respond so fast that you make many errors. (Occasional errors are okay.)
^^
The two categories that you are to distinguish are:
^^
UNPLEASANT vs. PLEASANT words.
^^
Press the "a" key if the stimulus is an UNPLEASANT word.
^^
But press "5" key if the stimulus is a PLEASANT word.
^^
</page>

The page element doesn't have any attributes, but simply contains the content of the page. The special character "^" will force a line break when the page is displayed on the screen. Otherwise, the instructions are word wrapped inside the page area.

Now let's define the rest of the pages in the script:

<page intro2>  
Just before each word that you are to categorize you will see one or more words and letter strings briefly flashed.^^
It is your task to IGNORE these briefly flashed stimuli. Respond only to the last, clearly visible word shown on each trial.
</page>

<page intro3>  
When you press the "5' key, you will see a stimulus to which you should respond.^^
As a reminder of the instructions for responding:^^
Press the "a" key if the stimulus is an UNPLEASANT word.^^
Press "5' key if the stimulus is a PLEASANT word.^^
</page>

<page ready>  
When you press the "5" key, a new block of trials at the same task as the last block will start.^^
Be ready for the first stimulus when you press the key.
</page>

<page end>  
The experiment is now concluded. If you have any questions or reactions to the experiment, please discuss them with the experimenter.
</page>

Finally, we'll define an instruct element that specifies how subjects can navigate from page to page. A script should have only one such element.

<instruct>  
/ nextkey = ("5")
/ prevkey = ("a")
</instruct>

The nextkey attribute specifies that subjects can press the "5" key to advance to the next instruction page, and "a" key to go back to a previous page.

Creating Text Stimuli

Creating Trials