Hi all

I have an event related task composed by a cue-target-response-target2-response2
the cue-target sequence produces a congruent or incongruent trial. I have two type of target. so I have four different conditions Cong1, Incong1, Cong2, Incong2.

my ReactionTimes data tells me that I have a facilitation In Cong1 (respect to incong1) but not in Cong2 (respect to incong2).
I would like to infer which areas can explain this

to explain the facilitation, I can make cong1 vs incong1 contrast with
1 -1 0 0
-1  1 0 0  

and cong2 vs incong2 contrast with
0 0  1 -1
0 0 -1  1

but how can i test

(cong1 vs incong1) vs (cong2 vs incong2) ??

which should emulate my reaction times differences
I think that it shouldn't be

1 0 -1 0
-1 0  1 0

which is instead Cong1 vs Cong2. not exactly the same I think.

(P.S. What an orrible explanation!)

thanks in advance
cheers
Alberto