Overview
The first step in building an experiment is to define all of the stimuli. Stimuli include text or pictures to be shown on a given trial, background text that remains on the screen throughout a block of trials, or a feedback text shown to the subject to indicate when to respond and whether their response was correct or incorrect.
First, let's define the pleasant words appearing in the upper and lower positions:
<text pleasanttop> / items = pleasant / position = (50%, 40%) </text>
<text pleasantbottom> / items = pleasant / position = (50%, 60%) </text>
This text element defines two sets of text stimuli, "pleasanttop" and "pleasantbottom", both of which have two attributes defined, items and position. The items attribute indicates where the text items are defined. In this case, they are defined in an item element named "pleasant" somewhere else in the script (more on this below). The position attribute specifies where on the screen the text should be presented. Both are presented at the 50% horizontal point of screen (i.e., the horizontal center). The pleasanttop stimulus is presented at the vertical 40% mark, which is 10% of the screen width above center. The pleasantbottom is presented 10% below center.
Now, lets define the items for this text element:
<item pleasant> / 1 = " HONOR " / 2 = " LUCKY " / 3 = " DIAMOND " / 4 = " LOYAL " / 5 = " FREEDOM " / 6 = " RAINBOW " / 7 = " LOVE " / 8 = " HONEST " / 9 = " PEACE " /10 = " HEAVEN " </item>
This item element is named "pleasant", which matches the name specified in the items attribute of the text element above. The item set consists of ten pleasant words. Note that the words are padded with spaces so that they are all of equal length when presented in a fixed width font.
Now, lets define the rest of the stimulus categories. First, we'll define the unpleasant words:
<text unpleasanttop> / items = unpleasant / position = (50%, 40%) </text>
<text unpleasantbottom> / items = unpleasant / position = (50%, 60%) </text>
and the unpleasant items.
<item unpleasant> / 1 = " EVIL " / 2 = " CANCER " / 3 = " SICKNESS " / 4 = " DISASTER " / 5 = " POVERTY " / 6 = " VOMIT " / 7 = " BOMB " / 8 = " ROTTEN " / 9 = " ABUSE " /10 = " MURDER " </item>
It's a good idea to include instruction text that reminds participants how to respond to the various stimuli. We can do this by presenting text on the screen that are shown in the background throughout a block of trials. So, let's create the instruction text stimulus that reminds the subject to pronounce the upper word and press the spacebar if they see '!'.
<text taskreminder>
/ items = ("Pronounce the top word and press the spacebar if you see the '!'")
/ position = (50, 15)
/ txcolor = (0, 0, 255)
/ fontstyle = ("Courier New", 12pt)
</text>
The reminder stimulus is a bit different than the previous stimuli. First, rather than defining the items in a separate element, we've simply listed the single item directly in the attribute. This inline syntax is a convenient way to define small item sets for things like instrutions, focus stimuli, and masks. Also, the position attribute specifies that the text should be displayed at the top of the screen. Finally,the txcolor attribute specifies that the text should be blue rather than the default color black. Colors in Inquisit are specified as a mix of red, green, and blue components; the txcolor attribute specifies 0 intensity for red and green components, and the maximum intensity 255 for the blue component, producing a nice blue color.
Now, lets define the target stimuli '!'. To do this, we create two text stimuli, one of which presents the target in the upper position, and the other which presents it in lower position:
<text targettop>
/ items = (" ! ")
/ position = (50%, 40%)
</text>
<text targetbottom>
/ items = (" ! ")
/ position = (50%, 60%)
</text>
Finally, lets define a focus stimuli that will appear in the center of the screen prior to the two words:
<text focuspoint>
/ items = (" + ")
</text>
|
Overview
|
Creating Instructions
|