How The Brain Learns To See

Conventional wisdom has it that the human brain is unable to learn to see after age 5 or 6, diminishing hope for the restoration of sight to those blinded at an early age.  However, new research published in the Journal of Psychological Science suggests the conventional wisdom may be incorrect:

This work builds on a 2007 study in which Sinha and graduate student Yuri Ostrovsky showed that a woman who had had her sight restored at age 12 had nearly normal visual processing abilities. These findings were significant since they challenged the widely held notion of a "critical age" for acquiring vision.

However, because they came across the woman 20 years after her sight was restored, the researchers had no chance to study how her brain first learned to process visual input. The new work focuses on three adolescent and young adult patients in India, and follows them from the time of treatment to several months afterward. It suggests that "not only is recovery possible, but also provides insights into the mechanism by which such recovery comes about," says Sinha.

…[The] results suggest that movement patterns in the world provide some of the most salient clues about its constituent objects. The brain is programmed to use similarity of dynamics to infer which regions constitute objects, says Sinha. The significance of motion may go even further, the team believes. It may serve to "bootstrap" the learning of rules and heuristics by which the brain comes to be able to parse static images.

…In addition to understanding how the human visual system works, the findings could help researchers build robots with visual systems capable of autonomously discovering objects in their environment.

"If we could understand how the brain learns to see, we can better understand how to train a computer to do it," says Ostrovsky.

Fascinating stuff, especially the possible role of motion in the learning process—which makes a lot of sense to me, given what we already know about the role of novelty in learning and perception.  This is also the latest of many things I’ve read in the last few years that the brain may exhibit greater plasticity later in life than was once assumed.

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