Plaid Motion


A sine-wave plaid is created by superimposing two drifting sinusoidal gratings. The plaid on the right contains one component moving downwards and a second moving leftwards. The two components are also shown side-by-side below. When superimposed, the two grating components usually lock together to form a rigid pattern - the plaid - which drifts in a direction that is determined by the speed and direction of the components. The plaid on the right drifts downwards to the left.
Plaids have been used to investigate how motion signals from local 1-D contours (the bars of the component gratings) are integrated to construct the motion of 2-D shapes (the plaid). Adelson & Movshon's (1982) 'intersection-of-constraints' or IOC model relies entirely on the 1-D signals, but other models have proposed that spatial features such as the blobs created by the superimposed components can also affect perceived plaid direction (e.g. Kim & Wilson, 1993).
Adelson, E. & Movshon, A. (1982) Phenomenal coherence of moving visual patterns. Nature, 300, 523-525.
Kim, J. & Wilson, H. (1993) Dependence of plaid motion coherence on component grating directions. Vision Research, 33, 2479-2489.
Rust, N. C., Mante, V., Simoncelli, E. P., & Movshon, J. A. (2006). How MT cells analyze the motion of visual patterns. Nature neuroscience, 9, 1421-1431.