…\DirectRT\samples\5- other features\14 IAT-Practice

…\DirectRT\samples\5- other features\15 IAT-Race

Sample Description

"I've tried the DirectRT implementation of the IAT. It worked like a charm and has an appearance very similar to the lab procedures we've been using for the last few years."

 -Anthony Greenwald
 Co-Creator of the IAT
 University of Washington

These samples were designed as a template for conducting IAT sessions with a variety of stimuli. Since the typical design of an IAT is rather complex, you can use this sample as a reference when building your own IAT, or you can simply copy it and substitute your own stimuli and scales—and voila! A nearly instant IAT!

If you're new to DirectRT I suggest you run through the tutorials before attempting to follow the IAT input file (this is kind of advanced stuff).

Some things to notice:

The "IAT-Practice.csv" sample input file in the "14 IAT-Practice" file folder contains 5 blocks of trials. In this sample, we are only interested in data from blocks 3 and 5—consequently, we use a block ID of 0 for the other blocks so that they will not be written to the data file. We also use an optional comment column (!Step) to identify which block (or Step) the trials belong to.

The bgr column contains all 0's because the order of the blocks is not randomized. The wgr column contains identical values for all items within blocks 1, 2 and 4 so that the items within each of those blocks will be randomized. In blocks 3 and 5 alternating patterns of wgr values allow us to alternate between randomly ordered adjectives and targets. Note that the instruction screens always have a wgr value of 0 so that they will stay where they are.

In the time column, some trials specify "rt:23,18" and others specify "rt:18,23". This tells DirectRT which response is correct since the correct response is always listed first.

Now take a look at the "15 IAT-Race" folder. In this sample, we have

Adjective1 = Good, Adjective2 = Bad

Target1 = White, Target2 = Black

These could be switched with whatever you like.

The first Stim column contains the scale that should appear on screen. On the first trial, the scale is "a2-a1." Take a look at the image file in the stim folder called "a2-a1.bmp." It's a label that reads "bad - good". That's because a2-a1 means adjective2 (bad) on the left and adjective1 (good) on the right.

Later the scales get more complicated because you have to have an adjective and a target on each side. E.g., look at "a2t1-a1t2.bmp." You'll see adjective2 (bad) and target1 (white) on the left and adjective1 (good) and target2 (black) on the right.

Do you see how this could act as a template? You wouldn't have to change the input file—just the stimuli. If your targets were "me" and "other", instead of "white" and "black", you could just replace "white" with "me" and "black" with "other" on each of the scale graphics.

The same goes for the second stim column. In the column you see that a random stimulus is drawn from the text files "adjective1.txt", "adjective2.txt", "target1.txt" and "target2.txt". Take a look at the adjective1.txt file. Since adjective1 = "good," the stimuli in this stim list are words like "JOY", "LOVE" and "PEACE." You could simply replace these words with ones representative of whatever you're using as adjective1.

A couple final notes, you may want to shorten the trial interval in this experiment to make the "flashing" between trials less pronounced. To do this, click on "Options" in the style file, IAT.drt. Remember though that DirectRT prepares the next trial during the trial interval, so be sure to give it at least 50-100ms.

The scales in this study were made with a graphics programs called Fireworks by Macromedia. It's a great program for putting together formatted text and saving it as .bmp graphics that you can use in DirectRT. A free trial version is available from https://creative.adobe.com/products/fireworks. If you get it, you can modify the source files used for this sample that are located in the Fireworks subfolder.