Virtual robots duped by illusions help to explain human vision. A study by researchers at UCL (University College London) explains why humans see illusions by showing that virtual robots trained to ‘see’ correctly also – as a consequence – make the same visual mistakes that we do. The study, published in the latest edition of PLoS Computational Biology, shows that illusions are an inevitable consequence of evolving useful behaviour in a complex world.
Illusions are defined in the Oxford English Dictionary as “something that deceives or deludes by producing a false impression.” Visual illusions, such as the ‘Hermann Grid Illusion’, trick the viewer into misinterpreting – in this case – shades of grey. The study’s senior author, Dr. Beau Lotto, UCL Institute of Ophthalmology, said: “Sometimes the best way to understand how the visual brain works is to understand why sometimes it does not. 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.” To address the question of why humans see illusions, researchers at the UCL Institute of Ophthalmology used artificial neural networks, effectively virtual toy robots with miniature virtual brains, to model, not human vision as such, but human visual ecology. Dr David Corney in Dr. Lotto’s lab trained the virtual robots to predict the reflectance (shades of grey) of surfaces in different 3D scenes not unlike those found in nature. Although the robots could interpret most of the scenes effectively, and differentiate between surfaces correctly, they also – as a consequence – exhibited the same lightness illusions that humans see. Dr. Lotto said: “In short, they not only get it right like we do, but they also get it wrong like we do too. This provides causal evidence that illusions represent not the world as it is, but what proved useful to see in one’s past interactions with the sources of retinal images. The virtual robots in this study were driven solely by the statistics of their training history and used these statistics as the basis of their correct and subsequent incorrect decisions. Similarly, we believe the human brain generates perceptions of the world in the same way, by encoding the statistical relationships between images and scenes in our past visual experience and uses this as the basis for behaving usefully and consistently towards the sources of visual images.” more... http://www.ucl.ac.uk/media/library/robotillusions _______________________________________________ NetBehaviour mailing list [email protected] http://www.netbehaviour.org/mailman/listinfo/netbehaviour
