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  • strange blanks...

    Hi!
    First of all, I would like to wish you a happy new year!

    I have a strange problem with SuperLab...
    I have programmed a Posner-like experiment :
    1/ fixation cross between two rectangles (so 3 events - rectangle left/rectangle right and fixation cross in the center - presented in the same time), for 1000 ms
    2/ a cue (photo) appears in lieu of one of the rectangle (or not at all) (again 3 events in the same time), even for 17 ms or 500 ms
    3/ a mask hides the photo (same screen as the fixation cross one - again 3 events in the same time), even for 17 ms or 50 ms
    4/ a target (a point) appears in one of the rectangle and have to be detected asap by the participant (again 3 events in the same time), maximum 2000 ms

    The problem is : there are systematic long blanks (for about 2-3 seconds) between the cue and the target, and the mask does not appear at all.
    I really don't know what is the problem - I have tried several things but it's always the same problem… It's very problematic because the timing of the task is very important in this experiment.

    Does anyone have an idea of what could be the problem here?

    Thank you in advance

  • #2
    Happy new year to you too.

    Question: how are you masking the visuals?

    Please attach your experiment files; it would be very helpful. Click File > Create an Experiment Package .

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    • #3
      Thank you for your reply.
      For the mask, I have presented again the same screen as the "fixation cross" one : fixation cross between two rectangles. I have copied and pasted the three events from the "fixation cross" screen and adapt the presentation duration, but it doesn't work...
      Please find attached the file. This is a complicated task, with a lot of types of trials, using almost always the same events).
      I hope that you will have a good idea to help me, otherwise I think that I will have to repeat the programming from the beginning!!
      Thanks!
      Attached Files

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      • #4
        Thank you for attaching the .sl5 file, but I am missing the media files in order to get this experiment running.

        Please click File > Create an Experiment Package. This will conveniently package all relevant files into a single .zip file.

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        • #5
          Sorry for my late answer, I was out of the office for several days...
          Please find attached the experiment package - I hope this will work with the photos...
          Attached Files

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          • #6
            I am getting a server error when I try to download your attachment. Maybe we should try another way to look at your files; please check your private messages.

            Comment


            • #7
              Thank you for sending your experiment.

              By ending your "invisible" events immediately rather than by their time limit, I have removed the delay that you were mentioning.

              You've also mentioned the mask not appearing at all. This wasn't the case for the experiment that you have sent me; however, such an issue likely has to do with how you erase the screen. For your design, only the first event of each trial needs to do so; your events share the same size and location so they will draw over each other anyways.

              In the future, please consider using stimulus lists. It can drastically reduce experiment size and maintenance.

              Please let me know if issues persist.

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              • #8
                Dear Arman,
                Thank you for your message.
                I indeed used stimulus lists for my experiment, except for the practice session.
                Whatever, during the WE, I have re-programmed the whole experiment, because I have to begin the recruitment of participants this week.
                The new experiment was OK, except for supraliminal trials (where the cue is presented for 500ms rather than 17ms). As you suggested, I have corrected the ending of the first event (when there was several events presented simultaneously) and this has resolve the problem - thank you so much!!
                Best regards
                Gaëlle

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