| These animations were created by rotating a black square over four
white circles, or a blue square behind four holes in a black surface. Surprisingly, both squares appear to "breath", they contract and expand as they rotate
(Meyer & Dougherty, 1992;
Shiffrar
& Pavel,1992). This is strong evidence that motion integration
does not use a rigidity constraint (Ullman,
1979). In principle, assuming rigidity to integrate successive frames
one could recover the rotating square. However, the local perpendicular
components at the square sides prevail here, generating the deformation. |
