[lolinder]

But has that been your experience with the full moon specifically? That thing is surprisingly bright—I'm thinking less about direct visibility of the orb than I am about just the general illumination in the area.

And again—the effect size is much smaller for the urban group than the non-urban groups, so I'm not suggesting that the light is starkly noticeable if you're not looking for it, just that it's probably detectable by the human eye and processed from there unconsciously.

In my mind you'd have to literally be unable to detect the difference in light between full moon and no moon (with a sensor with similar sensitivity to our eyes) before speculating about human gravitational senses becomes a rational move. We know we have eyes, and we know that what they're wired up directly to frequently surprises us.