Becoming Hungry to Learn #1

What are the limits of human learning?

This is a fascinating question, that received for many years a negative answer, based mostly on the idea that it is not possible to alter a hugely complex system, like our brain, without disrupting it.

There are modern fairytales where mermaids, dragons and usual magic take the form of experimental discoveries about the neural system. The story of Susan R.Barry [1] is one of them.

When neuroscientist Sue Barry was fifty years old, she took an unforgettable trip to Manhattan. As she emerged from the dim light of the subway into the sunshine, she saw a view of the city that she had witnessed many times in the past but now saw in an astonishingly new way.

Skyscrapers on street corners appeared to loom out toward her like the bows of giant ships. Tree branches projected upward and outward, enclosing and commanding palpable volumes of space. Leaves created intricate mosaics in 3D. With each glance, she experienced the deliriously novel sense of immersion in a three dimensional world.

Barry had been cross-eyed and stereoblind since early infancy. Stereoblindness is the inability to see in 3D, resulting in an inability to perceive stereoscopic depth by combining and comparing images from the two eyes. Individuals with only one functioning eye always have this condition; the condition also results when two eyes do not function together properly.

After half a century of perceiving her surroundings as flat and compressed, on that day she was seeing Manhattan in stereo depth for the first time in her life.

As a neuroscientist, she understood just how extraordinary this transformation was, not only for herself but for the scientific understanding of the human brain.

Scientists have long believed that the brain is malleable only during a “critical period” in early childhood. According to this theory, Barry’s brain had organised itself when she was a baby to avoid double vision – and there was no way to rewire it as an adult. But Barry found an optometrist who prescribed a little-known program of vision therapy; after intensive training, Barry was ultimately able to accomplish what other scientists and even she herself had once considered impossible.

Her description of the feelings she experienced during the recovery is beautiful and vividly report the sensations experienced during an intense reshaping of the visual and motor cortex. It is a revelatory account of the brain’s capacity for change and the fact that such perceptual changes can happen at an advanced age open new exciting perspectives.

"There is no end to our improvement"

Mosche Feldenkrais

[1] Susan R. Barry, Fixing my gaze