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Randomization problems

Hello, I’m trying to create a cognitive psychology experiment (one-back task). I have several pictures as stimuli. I need to present some of them in a specific order (for instance a specific stimulus supposed to be in 15th or 17th place) and the other stimuli supposed to change randomly across participants. I had trouble doing it. PsychoPy present pictures in a random order but does it for every picture. I have to organize them as some pieces of them randomizing separately.

Some of the pictures also supposed to come after one another. I created an excel file, but again, these orders do not change appropriately as they have to, across participants.

I assume that there are some ways to organize these stimuli in the builder but I have no idea how to do it. I hope I explained it clearly? Can you please help me? :frowning:

Hi There,

This requires some custom code. As with all things involving there are many ways to do this. As this is a question many people ask I put together a quick demo here that I hope you may find helpful Rebecca Hirst / custom_randomisation_demo · GitLab

Here participants are presented with a set of words, certain words are in fixed positions (as defined by the conditions file) with the interleaving words in a randomised order. The same principle will apply for any stimuli you are presenting (e.g. images, sounds).

Hope this helps,
Becca

I’m working on it. Thank you so much for your help!