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,

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