when you start the program the big blob on your screen should be green. In 1-5 seconds, it will turn red and make a loud noise. Click it the moment you see it turn red or hear the pop noise. This measures in hundredths of a second.
This is probably not 100% accurate because if it is i just beat the official world record by a fair amount, so take your time with a grain of salt. average human reaction times: visual stimulus: 0.25 seconds. audio stimulus: 0.17 seconds. touch stimulus: 0.15 seconds. Also, one of my friends got 0 milliseconds. I am serious. (reset world record though so its more fun). I will also give you a shoutout if you manage to get 0. I also manage 0 ms. Amogus. if you read comment amogus.
