Robots See Optical Illusions Just Like People

Researchers at the University College London's Institute of Ophthalmology are getting a better understanding of optical illusions by studying robots trained to see like humans see. The team, lead by Dr. Beau Lotto, found that the robots see not only the same realities, but also the same optical illusions that people see.

See sample optical illusions below...See sample optical illusions below...The researchers used artificial neural networks--basically virtual toy robots with miniature virtual brains--to model human visual ecology. Although the robots could interpret most of the scenes effectively, and differentiate between surfaces correctly, as humans do, they also exhibited the same lightness illusions that humans have.

"Sometimes the best way to understand how the visual brain works is to understand why sometimes it does not," said Lotto. "Thus lightness illusions have been the focus of scientists, philosophers and artists interested in how the mind works for centuries. And yet why we see them is still unclear."

Based on the study's results, the researchers think they may know why we are prone to optical illusions. As Lotto explained, the study provides evidence that illusions don't represent the world as it is, but, rather, they represent what was useful to see in a person's past perceptions. The human brain generates perceptions of the world by encoding the connections between images and scenes we've seen in the past, and then uses this information to see things consistently--which would be most useful for basic survival.

"The study also suggests the first biologically-based definition of what an illusion is: the condition in which the actual source of a stimulus differs from its most likely source," Lotto explained. "When we see an illusion we are seeing the most likely source of the image given history."

Examples of Lightness Illusions from lottolab . All images copyright by Beau Lotto.

Does the left square look dark gray and the right square look light gray? In reality, they are the same color.

Does the top block look dark green and the lower block look light green? Again, they are identical.

Does the blue circle in the shadow on the right appear brighter and lighter--as if it's illuminated by light--compared with the blue circle on top? Actually, they're the same color.

The square patch in the middle on the bottom may appear lighter than the other two patches on the dark stripes above, but all three square patches are the same.

The tile in the shadow under the desk may look white, and the tile to the right of it may look black. But again, these two tiles are the same color.

Want proof? For "masks" and more illusions, visit lottolab .

Via: University College London

Lisa Zyga
Science Blogger

Oct 3, 2007
by Anonymous (not verified)


yeah, i checked their website, and it's indeed amazing how our brain fools us. some illusions are working better than others, but damn, they're good !