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repeat trial once max

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  • repeat trial once max

    Hi, all,
    I am building a stop-signal task in which I want to limit stop trials to be presented only once or two in a row maximum but no more.

    So - go, stop, stop, go, stop, go

    but not - go, stop, stop, stop, go

    I tried to solve this by using a stop counter that increments to 1 every time a stop trial is presented, and then this parameter is reset every time a go trial is presented, and under trial rules choosing present only when stop counter is <2.

    The problem is that this will not allow the stop trial to be presented at the end of a given block in which the third and second to the last trials are stop, stop.

    I think I've worked around this problem by specifying a second rule for stop trials (attached). There are 64 trials total, 16 stop trials and 48 go trials.

    For stop trials, present trial only if the following criteria are met:

    Parameter "Stop counter" <2 OR
    Number of times this trial has been presented <16 AND
    Number of trials presented in block = 63

    This seems like it should work, but testing is difficult since presentation of two stop trials at the third and second to last trials in a block happens infrequently.

    Can anyone weigh in to let me know that this should work or alternative solutions?
    Attached Files

  • #2
    James, this would be faster addressed over the phone. Please call me at 1-310-548-9595.