Hi,
What I did to have the number of distractors vary across trials was to combine both conditions into one stimulus file, so now it looks something like this
67*15 94*25 121*15 166*25 etc
Then I was able to run it without any problems, but this gives me the same result if I just model the two conditions separately and do a glt contrast +east -difficult.
Since I have never worked with parametric designs before, how could someone design a good parametric design? I've seen some papers where they use param design in working memory tasks such as the n-back test.
Thanks
