All Kinds of Motion

When the black and white bars switch places, on a dark surround (left) the white bar appears to jump, but on a light surround (right) the black bar appears to jump. The bar with the higher contrast wins out. The mid-grey at which the motions balance is the arithmetic (not geometric) mean of the black & white, suggesting linear, not logarithmic processing of luminance. (Anstis & Mather, Perception 1986).

[quicktime width=”500″ height=”400″]http://anstislab.ucsd.edu/files/2012/11/AM-1.mov[/quicktime]
Ambiguous apparent motion. The two spots move either vertically or horizontally. Can you control the direction by willpower?

[quicktime width=”600″ height=”400″]http://anstislab.ucsd.edu/files/2012/11/ShapeFIxed1_2.mov[/quicktime]
Proximity: Motion is seen between nearest neighbors, horizontally on the left, vertically on the right. Shorter motion paths win out.

[quicktime width=”600″ height=”400″]http://anstislab.ucsd.edu/files/2012/11/ShapeChange1_2.mov[/quicktime]

The motion path changes gradually from a tall, skinny rectangle to a wide, flat rectangle. Perceived motion is always along the shorter side of the rectangle. Proximity wins.

[quicktime width=”600″ height=”400″]http://anstislab.ucsd.edu/files/2012/11/AMprime1.mov[/quicktime]

Visual inertia drives ambiguous apparent motion. Each spot appears to follow a horizontal path, not jumping up or down halfway across. Straight motion paths are preferred to going round corners.

[quicktime width=”600″ height=”400″]http://anstislab.ucsd.edu/files/2012/11/MultiAM1_2.mov[/quicktime]

Do these all move together or do they move individually?

[quicktime width=”600″ height=”400″]http://anstislab.ucsd.edu/files/2012/11/Occlude1_2.mov[/quicktime]

The center dot simply flashes on and off but it gets entrained by the other dots and seems to disappear and reappear from behind the green square. [V.S. Ramachandran]