Simon Crompton had a splendid article, titled “Don’t Believe Your Eyes,” in The Times Online last month. The article summarizes the recent research on illusions, with particular focus on the remarkable work of Dr. Beau Lotto. We excerpt portions of Crompton’s article below.
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Optical illusions are like magic, thrilling us because of their capacity to reveal the fallibility of our senses. But there’s more to them than that, according to Dr Beau Lotto, a neuroscientist who is wowing the scientific world with work that crosses the boundaries of art, neurology, natural history and philosophy. What they reveal, he says, is that the whole world is the creation of our brain. What we see, what we hear, feel and what we think we know is not a photographic reflection of the world, but an instantaneous unthinking calculation as to what is the most useful way of seeing the world. It’s a best guess based on the past experience of the individual, a long evolutionary past that has shaped the structure of our brains. The world is literally shaped by our pasts.
Dr Lotto, 40, an American who is a reader in neuroscience at University College London, has set out to prove it in stunning visual illusions, sculptures and installations . . . .
He explains his complex ideas from the starting point of visual illusions, which far from revealing how fragile our senses are show how remarkably robust they are at providinga picture of the world that serves a purpose to us. For centuries, artists and scientists have noted that a grey dot looks lighter against a dark background than the same grey dot against a light background. In the same way, colours appear different according to what colour they are next to. Why? The conventional belief was that it was because of some way the brain and eye is intrinsically wired. But Dr Lotto believes this is wrong.
He says it’s a learnt response; in other words, we see the world not as it is but as it is useful to us. His optical illusions seek to demonstrate this by proving that there are all sorts of ways you can make same-coloured areas look different, not just what colour they’re against. You can produce similar effects with the way we perceive shade and form too.
His illusions throw in a whole range of visual clues that prompt the brain to draw conclusions about the objects we encounter on the basis of past experience. . . .
What is happening is that our brain is taking into account all the visual clues it has learned over a lifetime. . . .
“Context is everything, because our brains have evolved to constantly re-define normality,” says Dr Lotto. “What we see is defined by our own experiences of the past, but also by what the human race has experienced through its history. The structure of the brain is a reflection of that history.”
What Lotto means by this is illustrated by the fact that different cultures and communities have different viewpoints of the world, conditioned over generations, an area that neuroscientists are just beginning to unpick. For example, Japanese people have a famous inability to distinguish between the “R” and the “L” sound. This arises because in Japanese the sounds are totally interchangeable.
“Differentiating between them has never been useful, so the brain has never learnt to do it. It’s not just that Japanese people find it hard to tell the difference. They literally cannot hear the difference.”
Dr Lotto is convinced that his experiments are grounding more and more hypotheses in hard science. “Yes, my work is idea-driven,” he says. “But lots of research, such as MRI brain scanning, is technique-driven. I don’t believe you can understand the brain by taking it out of its natural environment and looking at it in a laboratory. You have to look at what it evolved to do, and look at it in relationship to its ecology.”
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