Petter Plaids

G. Petter (1956) studied the segregation of black-on-black figures. Vallortigara & Bressan (1991) used Petter's observations to manipulate the strength of segregation between moving bars and a rectangular frame. You should see that when the bars and the frame are different in width, the bars tend to move perpendicularly to their orientation, as if the visual system disregarded the vertical motion of their terminators. When the bars and the frame are the same width, however, the bars tend to move downward. To best appreciate the difference, fixate the center of each rectangle alternatively.

created by Fauzia Mosca and Nicola Bruno