Stimulus from Johansson (1973; see also Hochberg & Fallon 1976).

Note: in all of the following demos, the middle dot's motion remains the same; only the motion of the top and bottom dots is changed.

Same as Demo 1, but only showing the middle dot.

Increasing the horizontal amplitude of the top and bottom dots' oscillation (all other parameters the same as in Demo 1).

Adding horizontal offset to the top and bottom dots.

Random dot kinematogram using the same motion structure. Here the middle dot corresponds to the central motion (inside the aperture), and the bottom/top dots correspond to the surround motion.

Same as Demo 4A, but without the surround (red) dots.

Same as Demo 4A, but without the center (green) dots.