You’re right. If you notice the instructions in the game, it encourages you to go as fast as you can. I keep the numbers up there just to make sure the voice recognition is working properly and to make the game seem more engaging.
But yeah, I agree: I think this does influence the results, since it makes it easier to be more random because you can essentially try to play in an adversarial fashion by adjusting your results according to feedback from the predictor itself.
In the original study, that wasn’t the case. They had a three-by-three grid of numbers and a metronome as well, which meant that they couldn’t slow down or speed up and had to go at a very specific rate with zero feedback until the very end.
Maybe I should add the equivalent of a "Hard" mode which makes the game more faithful to the original study.