Repeatedly Cycling Through the Same Subset of IDs per Participant

[Morgan Patrick]

Hello All,

I have a list of 16 stimulus IDs, and I need to randomly select 8 of those per subject. I need each participant to receive 4 cycles of this subset, ideally in random order each time. Is there a configuration in the selection tab that will ensure the same 8 IDs are chosen across all 4 cycles of the same participant? I believe permutation by subject will fix the order of the 8 samples across each cycle, which is not ideal.

Thanks!

[McFarlane, David]

Assuming that you want to run those 4 cycles of the subset within a single session, here is some rough idea of how I might go about this ...

I would divide the session into two phases, a setup phase and an experiment run phase.

For the setup phase I would have a List for the pool of 16 stimulus IDs, let's call it SetupList. I would run SetupList in Random order for 8 samples. The Procedure for SetupList would run some InLine code to build a secondary List from the 8 samples, let's call that SubsetList. I could build SubsetList as a main List that runs a Procedure, or build it as a nested List -- I would probably do the latter as it seems neater, so let's assume that. Nothing else happens during the setup phase.

For the experiment running phase I present trials using SubsetList as a nested List. SubsetList is set to use Random order, and to reset after one cycle (8 samples). So I could simply use SubsetList for 4 cycles of 8 samples each, and for each cycle I would get the sames 8 selected stimulus IDs in a newly randomized order.

-- David McFarlane