Figure Ground Reversal

Download/view model (then chose File> Save Page As, save with .nlogo extension).

Instructions: To run the applet click setup; step will advance the applet one timeframe and go will run it continuously. The Background-probability, Set-1-probability, and Set-2-probability sliders can be adjusted to vary the probability that any given pixel of either the background or picture will be purple. The picture drop-down menu allows one to chose either of two pictures.

 

Notice that with the sliders set to probabililties of 50%, you see only a noisy field in which no picture is visible. By changing the probabilities you should be able to detect a pattern in the noisy field. When you can just begin to detect a regular pattern, try stepping one time interval at time and notice whether or not the pattern is visible in single time frames. Clearly, the patterns are only statistical regularities and your visual system has evolved to detect statistical regularities.

 

Pattern based on the art of John Langdon.

 

Posted by Laura Cyckowski and Paul Grobstein 17 Oct 2009. Applet created using NetLogo, the availability of which is gratefully acknowledged.