I am trying to design an experiment where a 3x3 grid of letters is presented to the participant (9 letters). I want the computer to chose 9 random but, crucially, different letters (consonants) on every trial. I have created 9 stimulus lists each consisting of the same 21 consonants). I don’t want a repeat of the same letter within a trial. After the grid of letters is shown for 1000 ms, the participant should respond.
I have 2 problems that I’m hoping you can help me with:
I do not know how to have the computer randomly select different letters from each of the stimulus lists. I have randomized in the trial editor by choosing the “unpaired” option, so that any letter from any of the 9 lists is chosen on every trial. However, my problem is that the letters often get repeated within the same grid (e.g. DD)
I want the 3x3 grid of letters to be shown ONCE only on any given trial, and then for a response from the subject. However, as I now have it programmed, the grid of letters is being shown multiple times. I am not exactly sure why (although I have a hunch it is because of the randomization in the trial editor that I have selected) or how to correct this.
I very much appreciate any help you can give. I am attaching a copy of the experiment to this message.
IM 2015 superlab 5 version.zip (3.37 KB)