The Ouija board effect: minor amplitude but consistently aligned phenomena lead to significant movement of the collective, as if by magic.

"Where is the singular cause of this obvious macro behavior? There isn't one, therefore it must be magic!"

The trick is that the bits of variance are small and lost in the noise.

But because the variance is aligned across multiple entities, they stand out from the background noise strongly.

Not strength of the variance, but the alignment.

In particular in Ouija, the indicator starts off moving randomly, but the people moving it are interpreting it in a continuous feedback loop. As it starts looking like it's moving to a letter, if it makes sense, then it starts going there faster and faster as more of the people with hands on the indicator become aware of the implied hypothesis of the next letter and think it's plausible.

Other people will think magic is impossible and under-utilize this strategy.

But if you see that magic is real, you can deploy it very intentionally.