The "freezing rotation illusion" refers to decrease in perceived speed of a continuously rotating
central region when a swaying surround co-rotates. We observed the following effects for rotations: First,
when the centre and its surround are turning in the same direction, and their velocities are distinguishable,
the perceived speed of the centre is lower than its physical speed. Second, when the surround and the centre
are counter-rotating, the perceived speed of the centre is enhanced. Third, even when the surface size of the
centre matches the surface size of the surround, swaying of the centre is unable to induce significant
changes in the perceived speed of the surround, whereas swaying of the surround still induces changes in
the perceived speed of the centre.