This is a demonstration of silencing by background motion, created by Jordan Suchow and George Alvarez.
Instructions: Keep your eyes fixed on the small white mark in the center. At first, the scene is stationary and it's easy to tell that the dots are changing. A few seconds later, the scene begins to move and it becomes increasingly hard to notice that the dots are changing.
But play the movie again, this time looking directly at one of the dots. You will see that, in fact, the dots had been changing the whole time—you just didn’t notice it. This failure to detect that moving objects are changing is silencing.
The full set of demos is available at http://bit.ly/cAVMEU [harvard.edu].