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  • delayed feedback

    Hi all,

    I'm trying to set up an experiment that involves a movie clip being played continuously. While the movie is playing, the participant presses a key on the keyboard. Upon keypress, a tone is provided as feedback. I would like the tone delivered NOT instantaneously, but at some time delay.

    So far, in attempt to add the delay, I inserted an ISI as a feedback to the key press, and the tone as a feedback of the ISI. I was not able to get the tone to be delivered. Without the ISI, the tone is delivered instantaneously.

    As a side note, I think my setup would work with non-movie stimuli.

    Hope someone can help!

    eve

  • #2
    Waveform editor

    Why not put some silence into the audio file? That is, if you have a 250 ms tone you want to play after 1 s, create a 1s "silent" sound and concatenate them with a waveform editor. The audio system will start to play back the file immediately, but no sound will be produced for 1 s.

    Greg Shenaut

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    • #3
      Thank you for your suggestion.

      I had previously suggested this to my lab, but they believed that SuperLab had this capability, which would be a bit more sophisticated, and we wouldn't have to generate so many different stimuli.

      If SuperLab tech support could verify whehter or not this implementation is possible, it would be greatly appreciated.

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      • #4
        Hi Eve,

        Welcome to the forums, long time no hear from you.

        Regarding your approach, you cannot provide a feedback for an event that is itself a feedback. However, you have an event present as many events as needed, e.g. when the participant responds, in the Event Editor's feedback tab, you can tell SuperLab to present an ISI event and an event to play the tone.

        Hisham.

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        • #5
          Hi Hisham,
          I decided not to bother you for awhile :P

          thanks for answering, but I wasn't clear in my original descriptions of the problem. If I were to follow your suggesting of presenting a series of events (i.e. movie, ISI, tone), would I be able to have the movie playing, and any time there is a key press, a tone is given while the movie is still on? I was successful at this only when the tone is asked as feedback immediately after a key press is made during the movie presentation. However, when I changed the feedback to be an ISI, and tone, it dosen't work. I believe this is what you're describing as event being used as feedback.

          I had tried what you suggested before posting, and the problem i ran into with this approach is that the events (in this case, would be an ISI and a tone) do not occur until after the movie is done playing. Maybe I did something wrong? Could I possibly send you my SuperLab file?

          What we need to happen is the following:

          1. Movie playing
          2. Upon key press, insert some time delay and a tone
          3. Movie continues playing; the key press should not terminate the movie presentation.

          Talk to you soon!

          eve

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          • #6
            Hi Eve,

            Yes, please send me the experiment. Up to 5-6 megabytes should come through just fine.

            Hisham.

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