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  • Response delay for last item

    I have four events in each trial. And the response of button 4 (the response for last item in each trial) is slower than then the responses of other 3 buttons.

    What can be the reason?

    Has anyone the same problem; the response to the last item in each trial is slower than the responses of previous items?

  • #2
    How much slower? What type of input device? Is this on the Mac or the PC? Is this the same experiment where you are randomizing events in the trial? Is the behavior different with a different input device?

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    • #3
      It is c.a 1 sec.slower. (the screen holds on for a while)....
      I have a RB-620 Response Pad. It is on the PC. Yes, it is the same experiment.
      The input device is not different.

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      • #4
        Is the problem that the screen stays up for a second or that the response time in the output file states that it took a second longer?

        Does it behave differently if you use the keyboard for input instead of the RB-620?

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        • #5
          Dear Hank,

          I am using a test version, therefore I can not see the output file..Despite I press the response button for the last event of a trial, the screen does not show immediately the next event (the first event of next trial)...It freezes up c.a 1 sec., then comes the next event.

          I tried it also with keyboard, and with more events, like 6, 12 etc..The problem is always the same, the first item of next trial is shown not immediately; the last event of previous trial stays on the screen, although the right key is pressed.

          I think superlab needs a time to begin with the next trial. Therefore at the end of each trial it takes a short time to begin with the next trial (or maybe because I am using images as events)

          Could this problem be solved? Otherwise it is impossible for me to use superlab for my experiment..

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          • #6
            I noticed this problem does not happen if each trial consists of one event..

            But I want to show c.a 230 images in turn.. And sequential trials belong to the same repeating 12 item (event) sequence. Therefore it is useful for me to have 15-20 repetitions (trials) of this 12 item sequence..

            Otherwise I should define 230 events for 230 trials

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            • #7
              Hello Cigdem,

              With that many trials, you really should be taking a look a the stimulus lists feature in SuperLab 4. It is described in the tutorial that comes with the SuperLab help file (click on Help menu and select Help Contents) in case you haven't gone through that tutorial yet. Many SuperLab 2 users feel that they can bypass this tutorial, but there are lots of new features in SuperLab 4 and it would be a good idea to take a look at it if you haven't already.

              Cheers,

              Hisham.

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              • #8
                Dear Hisham,
                thanks your for answer!

                But will stimulus lists feature solve this problem?:
                I think superlab needs a time to begin with the next trial. Therefore at the end of each trial it takes a short time to begin with the next trial (or maybe because I am using images as events).

                Cheers,
                Cigdem

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                • #9
                  Dear Hisham,
                  I am using superlab 4.

                  I have a lot of trials.But the trials consist of the same 4 pictures..Only the locations change for the trials..

                  It seems that RSVP and stimulus lists are not possible for pictures.

                  Could you please send an example experiment, where in stimulus lists 4 different pictures are used..

                  The experiment should show these 4 pictures everytime in different 4 locations..The locations change randomly, and subject should press one button for each location..And it should be alltogether c.a 200 trials.

                  I hope you can help me,
                  Cigdem

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                  • #10
                    Memory issues?

                    Are all of the image files about the same size? And, are they unusually large? It occurs to me that you could get a delay from the overhead of loading or freeing memory for very large images. Also, do you preload all of the images, or load them as you go? (Experiment>Options...>Memory Management) Whichever method you're using now, try the other. The probability that very large image files are slowing things down is greater if the computer is low on RAM. If this is the case, you also could try unloading as many other programs as possible before running SuperLab.

                    (Just some random thoughts from a fellow Superlab user.)

                    Greg Shenaut

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                    • #11
                      Dear Greg,
                      thank you, I will try it..
                      But I have a lot of other problems

                      Do u know maybe how to use: Conditional branching (if/then/else) .There is no info in tutorial

                      cheers,
                      Cigdem

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                      • #12
                        one question

                        Dear Greg,

                        I have one question to you. If we want to have intertrial interval btw.events, what is the best way?

                        1: Marking both of them: After a correct response from the participant and or a time limit (for exp:500 msc), whichever happens first.

                        or 2: As a feedback choosing event: empty text (500 msc).

                        But anyway both of the solutions have problems for me..The events (pictures) are frozen, and no feedback (empty text) is shown (maybe because I am trying to use stimulus lists?)...Without intertrialinterval the experiment is going on..but I must make intervals

                        thanks in advance ,

                        Cigdem

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                        • #13
                          If you want a constant delay after the keypress before another image comes up, then your best option--in the case of randomizing events within a trial--is to use feedback to present the ISI.

                          The reason that the existing picture stays on the screen is because there's nothing telling SuperLab to remove it. In the ISI event editor, there's a checkbox that says "Erase screen." This will give you a blank screen during the ISI.


                          ps. This post was moved to this thread from a completely unrelated thread. Please try to stay on topic within a single thread.

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                          • #14
                            Dear Hank,
                            Thank you for your quick answer!

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