Neither One Won
A flash, a click, and sometimes both. Both together is faster, and a race between them explains that. This page measures whether a race can explain how MUCH faster.
Press the key the instant you notice anything. Sometimes a flash. Sometimes a click. Sometimes both at once. Nothing to decide, nothing to get wrong, one key.
Both together will be faster than either alone, and that has a boring explanation from 1962: two processes are running and you move as soon as the FIRST one finishes. Two lottery tickets win more often than one. Nothing is combined, nothing cooperates, and the speed-up falls out of arithmetic.
true of every race, whatever the two channels do to each other
Which is why this is worth ten minutes. The race story is not a story, it is a ceiling, and both sides of that ceiling are things you are about to measure. People go through it.
Your audio output is late by some unknown amount, and unlike screen lag it belongs to only one of the two channels, which sounds fatal.
It cancels exactly. Every click-only time recorded here already contains that delay, because the clock starts when the page asked for the sound. On a both-together trial the same clock starts at the same moment. So the measured single-signal distributions are precisely the ones the inequality is written over, on a device nobody had to measure. No calibration, no correction to get wrong.
They will probably print nearly the same number, and that is the interesting part rather than a bug. The two differ by a product of two small probabilities, and at the fast end of a distribution a product of two small numbers is nearly nothing. Where a violation can be looked for at all, the weakest race and the fastest conceivable race agree. People beat both.
There is a boring explanation for a violation as well: two things at once are a bigger event, and a bigger event is more alerting. So one block swaps the click for a second flash on the other side of the screen. Same count, same suddenness, more light on the display than the click ever added, and only one sense involved.
One key, the space bar, or a tap anywhere on a phone. Six blocks, about nine minutes, the first unscored, escape aborts at any time. One trial in eleven has no signal at all and your presses on those are counted: a run over twenty percent of them is refused rather than scored, because a guess is a fast time in whichever condition it lands in. The wait before each signal is drawn from a distribution whose remaining wait never shortens, so there is no moment worth leaving early for. This one needs sound, and it checks before it starts.
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