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Problems with fixation cross

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  • Problems with fixation cross

    Hi there, I'm hoping someone can help me out here. I've just started using Superlab (4.0 at the moment) so apologies if the answer's obvious, I just can't find it anywhere.

    I'm presenting participants with 24 different faces for 2000 ms each. The order of these faces need to be randomized, but between each face I'd like to present a fixation point.

    Currently I have 25 events within the trial (24 faces and one image of a fixation point). I've linked each face to the event but the fixation point remains unlinked. I'm using a macro to display the fixation point (when number of trials in this block is equal to one, present event "Fixation Point") but it just doesn't seem to be working. The "Fixation Point" event lasts for 500 ms. Is there a more intuitive way of doing this?

    I thought I'd be inventive and use the "How to give a participant a break after N trials" tutorial on the Superlab site. It seems my ingenuity hasn't paid off though!

    I'd appreciate any kind of help here and sorry again if it's a dumb question...

  • #2
    If I understand what you want to do, I think there are two ways to implement it. First, you could define 24 trials, each with the fixation event plus one of the face events. Or, second, you could put the faces in a stimulus list and define a single trial that refers to the fixation event and the stimulus list. I suppose you could do it with a macro, but I think your macro is telling Superlab to present the fixation only once at the beginning of each block, and that doesn't seem to be what you want.

    Greg Shenaut

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    • #3
      The letter rotation experiment that is on the SuperLab 4 CD (and on the forum here) is set up using a stimulus list. To add a fixation in front of each letter, you would only need to create one event and link it to the trial.

      A macro is the hard way to do a fixation point.

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