Stroop Task: NR to second identical stimulus

I am designing a Stroop task with SuperLab similar to the one Hester, Foxe, Molholm, Shpaner,and Garavan described in NeuroImage 2005 (“Neural mechanisms involved in error processing: A comparison of errors made with and without awareness”).

In this Stroop design, the participants will press a key during all congruent conditions (i.e., when color word and font color match) but will NOT press a key during either (a) incongruent conditions or (b) after the same stimulus is presented twice in a row. I used a previous post (search for “Stroop”) at this forum to create several word lists, each with a unique font color, to correctly evaluate congruent vs. incongruent stimuli, but I am still having difficulty figuring out how to have SuperLab identify response patterns after two identical stimuli are presented back-to-back.

Any suggestions? I assume it involves a combination of codes and conditional statements, both of which I haven’t really come to grips with yet. Thanks!

Okay, I have designed a Stroop task in SuperLab that is coded to record congruent vs. noncongruent stimuli. At this point, I am having trouble getting the experiment to display at least 4 congruent stimuli before displaying an incongruent one. Regardless of what I put in the expression editor under Macros, I ALWAYS get exactly 4 congruents then 1 incongruent; what is the expression to get the programs to generate 4 or more (i.e., at least 4) trials before taking the path outlined by the conditional expression?

For example, I have tried “Number of Trials Presented in THIS BLOCK is greater that 3 trials”
and “Number of Trials Presented in THIS BLOCK is greater or equal to 4 trials” … I have added additional “Less than 10 trials” constraints to try and specify a range of values; I have even reversed the expression and true/false values (used less than or equal to 4) … all to no avail.

I’d really appreciate being shown what I assume is a simple problem for many here. Thanks!

Attached is the file, if this helps.

Error AwarenessGT.sl4 (15.2 KB)

In looking at your experiment, the congruent block contains 6 congruent trials (and nothing else). Are you wanting to switch to the incongruent block after 4, 5, or 6 congruent trials have been presented? In other words, are you trying to vary the number of congruent trials that are presented?

yes, that is the idea

It is possible to vary certain aspects of the experiment at the event level, e.g. vary the position of the stimulus on the screen. But unfortunately it’s not possible to vary the number of trials presented.