alt Hacker NewsIt reminds a bit of musicians tracking rhythm. You can somehow feel a beat after a bit practice even when not directly paying attention to it and it's not too hard to associate it with an increasing counter (somehow). It sounds hard, but it is quite doable.
> You can somehow feel a beat
If you play in an orchestra, you might have the visual memory of the conductor and their time signature motions helping you along.
The somewhat jarring tick tock of a digital metronome can also be encoded into a sort of background track that plays more or less automatically in your head.