Silas: @Caledonian: That's an interesting point. But are you sure the effect you describe (at science museums) isn't merely due to the brain now seeing a new color gradient in the image, rather than randomness as such? Don't you get the same effect from adding an orderly grid of dots? What about from aligning the dots along the lines of the image?

Yep. Adding a set of coherent modulations will do better than noise to improve your sensor, because you're guaranteed to get at least some modulations of a sufficiently high level, and you can subtract out the modulations afterward to arrive at a superior picture of the environment.

Remember, Eliezer_Yudkowsky's point was not that randomness can never be an improvement, but that it's always possible improve beyond what randomness would yield.

Lotta commenters seem to have entirely missed this.