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Help, I need to fix this experiment randomizing blocks

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  • Help, I need to fix this experiment randomizing blocks

    Hello and thank you very much in advance for your help. I have designed an experiment where each trial within a block corresponds to a series of stimuli (example trial 1 features an isi followed by cue then sound from particular side, then picture from same side, then another ISI and finally a respond now page). The idea is that participants are supposed to focus on a fixation point and then when presented with an image on either the left side or the right side and a sound on the left side or the right side at the same time, they had to choose whether the sound came from the left or the right. It's a ventriloquist experiment replication. So in my first block, I have 1/4 left sound-left image, 1/4 right sound-right image, 1/4 left sound-right image, 1/4 right sound-left image. In the other blocks the fractions change. The problem is randomizing these blocks which there doesn't seem to be a way to do. Is there a way to solve this or a way around it? I was thinking stimulus list but I'm not quite sure.

  • #2
    What version of SuperLab are you using, SuperLab 4.5 or SuperLab 5? I always encourage using stimulus lists within experiments.


    • #3
      Superlab 4

      I am using Superlab 4. As for the stimulus list question, how would I combine an image and a sound to happen at the same time? Admittedly I am not too strong on the stimulus list part.


      • #4
        In the SuperLab 4.5 manual within Chapter 6, there is a section titled, "Presenting a Sound and Visual Stimulus at the Same Time." It has detailed instructions how to set this up in your experiment. The PDF version of the manual can be found from the following link:


        • #5
          Thank you very much and I did that. It's more like I want a way to randomize specific blocks. Also another problem has come up where when I set up sounds in audacity and export them into a .wav format, when using Superlab, they get clicks at the end. How would I go about resolving this? I've tried editing the sound in audacity, and doing all sorts of fades in and outs. I've checked the speakers. It seems that superlab adds that clicking sound.


          • #6
            There was a bug in an earlier version of SuperLab 4.5 that had this type of problem. If you are not using SuperLab 4.5.4, please download it from the following link:

            If you do have the latest version and you continue to have issues, I think posting your experiment would be helpful. Please post your experiment as an Experiment Package. This can be found under the File menu within SuperLab.