hi everyone,
i came across the following problem, your assistance will be greatly appreciated
my design is built like this-
participants see stimuli which can be from 6 relevant conditions
from time to time a catch question appears
so in total i have 7 conditions- 6 experimental conditions and 1 irrelevant "catch" condition
in spm (version 5) i am using the "mutliple conditions" option and loading an onsets file which is a table with 2 coulmns : the timepoint and the condition(1-7)
later on i define contrasts between the 6 relevant conditions and i ignore the irrelevant condition (7)
the thing is this:
for each of the 6 relevant stimuli types (but not for the 7th condition), i am measuring the response times.
i need to covary this out since it differs significantly from one condition to another.
how can i achieve this?
thank you very much,
-michael gilead
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