Comment by tgbugs

A fully psychometric version of this that explores more than just the fovea could be created by varying the scale parameter (if you crank it up high enough you can see the movement in the periphery). The additional component you would need is to have trials where the subjects has to report whether a particular region (could even be cued with a red circle, I don't think it needs to be random) is actually moving or not while fixated on the center. There are clearly cells that detect this kind of motion in the periphery but they need larger visual input, possibly because the receptive fields of the cells that feed in are larger out there.