Perceptual compromise between apparent and veridical motion indices: the unchained-dots illusion.

A new motion illusion based on dot-trajectory misperception is presented. The illusory effect can not be explained by the aperture problem unlike some previous illusions characterised by misperception of motion direction. We propose an explanation in terms of 'perceptual compromise' between an original type of apparent motion and the veridical motion. Several demonstrations are presented in support of that hypothesis.