Creating Trials

The next step is to define the different kinds of trials that will be used in the IAT task. Trial elements control which stimuli are presented and how the subject may respond to those stimuli. There are six types of trials used in this task depending on which semantic category of stimulus is presented and which response key is assigned as the correct classification of the category.

First, let's define trials involving pleasant words, which are always assigned to the right response key.

<trial pleasant>  
/ stimulusframes = [1=pleasant]
/ validresponse = ("a", "5")
/ correctresponse = ("5")
</trial>

The trial element's name is pleasant . On each line of data in the data file corresponding to this type of trial, this trial name is written.

The stimulusframes attribute defines the stimulus presentation sequence of the trial. The entire presentation sequence will consist of as many frames as are specified in the frames attribute (only 1 in this case). A pleasant word is presented on the first frame, after which Inquisit begins waiting for (and timing) the subject's response.

The validresponse attribute indicates that the subject may respond by pressing either the "a' or the "5' key, after which Inquisit will advance to the next trial. The correctresponse attribute indicates that only the "5' key is considered a correct response on this type of trial.

The definition of the other trial elements are the similar to pleasant , differing only in the type of stimulus presented and the response that's considered correct.

Here's the definition of trials with unpleasant words where "a" is a correct response:

<trial unpleasant>  
/ validresponse = ("a", "5")
/ correctresponse = ("a")
/ stimulusframes = [1=unpleasant]
</trial>

Next come trials with insect names classified with the "5" key:

<trial insright>  
/ validresponse = ("a", "5")
/ correctresponse = ("5")
/ stimulusframes = [1=insect]
</trial>

Trials with insect names classified with the "a" key:

<trial insleft>  
/ validresponse = ("a", "5")
/ correctresponse = ("a")
/ stimulusframes = [1=insect]
</trial>

Trials with flower names classified with the "5" key:

<trial flowright>  
/ validresponse = ("a", "5")
/ correctresponse = ("5")
/ stimulusframes = [1=flower]
</trial>

Trials with flower names classified with the "a" key:

<trial flowleft>  
/ validresponse = ("a", "5")
/ correctresponse = ("a")
/ stimulusframes = [1=flower]
</trial>

The trials above capture the different combinations of stimulus category and correct response in the IAT.

Creating Instructions

Creating Blocks