Hi, I'm modelling a task in which participants perform the same cognitive task on a number
of stimuli which differ only in their color. I'm having trouble working out the best way to
model this and would love feedback.
I have stimuli of four different colors, with responses to each color split into correct and
A. If I consider modelling the process and then the color separately [i.e., regressors (1)
correct, (2) incorrect, (3-6) color], I think I'm likely to end up with a degenerate design.
B. If I model correct and incorrect responses by color [(1)blue-correct, (2)blue-incorrect,
(3)purple-correct...(8)] it seems intuitively wrong - I'm splitting variance for a cognitive
process that is almost identical between four different regressors (for both correct and
incorrect responses). I also think I lose a lot of power in each regressor's estimate.
I'm sure there's a relatively easy solution; any suggestions?