Thank you very much for your prompt response!

Quote

What do the subjects listen to during the first session? During the second session does each subject listen to only one of the two scrambling cases or both?

All subjects listen to the temporally intact story during the first session. Subjects then listen to only one of the scrambling cases. Slightly questionable study design, I know. It's from an open-source dataset!

Quote

I suggest that you build two separate models: one for the contrast of the intact vs scrambled versions using 3dMVM, 3dttest++, or 3dLMEr

This makes some sense. Just to clarify, could I use the same model that I've applied previously for this purpose, and just change my post-hoc GLT codings slightly? e.g.

-model 'Age+Gender+scram+(1|Subj)' \
-qVars "Age" \
-qVarsCenters 20.66 \
-gltCode intact 'scram : 1*intact' \
-gltCode longscram 'scram : 1*long' \
-gltCode shortscram 'scram : 1*short' \
-gltCode intactVlong 'scram : 1*intact -1*long' \
-gltCode intactVshort 'scram : 1*intact -1*short' \

Quote

and the other for the contrast between the long and short scrambled versions using 3dMVM or 3dttest++.

Again, just to clarify, if I were to run this in 3dLMEr, could I achieve this between-subjects contrast by removing all subject-level analyses of the 'intact story' from my input files table, only retaining the long and short scrambled versions of the story using the following model?

-model 'Age+Gender+scram+(1|Subj)' \
-qVars "Age" \
-qVarsCenters 20.66 \
-gltCode intactVlong 'scram : 1*intact -1*long' \
-gltCode intactVshort 'scram : 1*intact -1*short' \

If so, I'm a little confused. Why should these have to be run separately?

Thanks again for your help, Gang! I really appreciate it.