Thanks for you reply. I read the documentation and tried it. Good news is that the .log(“first”) does work, but the problem is that it seems that the key element must receive a response before the script can go on. If I disable the key after time out, the script will get stuck at the end of the trial; if I don’t disable it, it will record the keypress that doesn’t correspond to the Stroop trial but the comprehension question later in the trial (the response key for the comprehension question is the same as that of Stroop). Could you help me out?