Anything seem different?
[quicktime width=”500″ height=”400″]http://anstislab.ucsd.edu/files/2012/11/RampAE.mov[/quicktime]
Gaze at the fixation cross. This will adapt your eyes to a repetitively brightening patch (above) and a repetitively dimming patch (below). Watch until both rectangles turn it into a steady gray. You should see an aftereffect of apparent dimming (above) and apparent brightening (below). Try it again.
This shows the existence of transient visual pathways selective for gradual changes of luminance.