Hello,
I’m beginner and I would like to create experiment where participant see a visual stimulus （white square and press spacebar before the stimulus disappeared. At one of two conditions, responses before the stimulus disappeared will be given a picture of thumb up and the presentation time of white square would be decreased 10ms in nest trial, otherwise they would be given a thumb down picture and the presentation time of white square would be increased 10ms in nest trial; at another conditions, responses before or after the stimulus disappeared will be given a picture of equal sign, if responses before the stimulus disappeared, the presentation time of white square would be decreased 10ms in nest trial, otherwise the presentation time of white square would be increased 10ms in nest trial. I got all pictures. I don’t know how to write feedback code which depend on reaction time. Need your help guys. Example in attachment 
SID231016.psyexp (48.1 KB)
trialsloop_P.xlsx (9.1 KB)
