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Need help creating a replication


I’m having some trouble replicating an experiment by Yeshurun and Carasco, about attention and spatial resolution. It’s a texture segregation task, and I have to create 35 positions for my stimulus image, all along the horizontal meridian, and each stimulus appearance must be preceded by a cue - for example, if the stimulus appears on the left side of the screen, it has to be preceded by a clue on that left side, in the same position where the stimulus is supposed to appear.

I am having some trouble with randomizing the aforementioned positions, as they have to be presented in random order as the experiment goes, and I don’t really know how to connect each cue with each stimulus. Maybe there is a specific function in psychopy/python?

Also, there is another condition in the experiment - my stimulus has to appear in a texture matrix only half the time. Each probe in the experiment consists of two intervals, during each of them a texture matrix is presented. My stimulus has to appear in one of the matrices in random order - and this goes on for 288 trials in general.
I tried to specify this in code - half the time the stimulus has opacity 0, another half - 1, and all that in random order, but it doesn’t seem to work, the stimulus simply doesn’t appear.

Is there any way to fix this?

I’ve attached my experiment and the article itself.

replica_ann (2).psyexp (31.0 KB)

Thank you in advance for your answers!

Have you considered just using a conditions file rather than code to control your stimulus positions? The randomisation is then controlled by the settings in the loop dialog.