Change Blindness Experiment help.


I’ve been struggling to put together an experiment for a change blindness study, and I am out of ideas to get it working in Superlab, so wondered if anyone could help.
I’ve attached an image file that hopefully will explain the design better than I can write it down.

Basically an image (A) needs to appear on the right side of the screen for 3 seconds.

After 3 seconds a distractor will play on the left side of the screen (a video or an audio file, depending on the participant group).

The distractor will play for 500 milliseconds, and at the 250 millisecond mark, the image (A) on the right side of the screen will change to a new image (B).

Once the remaining 250 milliseconds of the distractor have finished it will be removed from screen (if its the video file) and then the new image (B), will be displayed for 3 seconds.

The process of distractor and image change will happen again (image B turning back to image A), and the process will loop all over again either for 4 times or until the participant presses a button to save they have seen a change in the image.

I need to measure reaction time from the participant, when they notice the change in the image. So this could be during the first loop or it could be through the 4th, but the RT can’t reset each time it loops, it needs to keep track from the onset of the first loop beginning.

Thanks for any help