The Sea Gypsies

The Sea Gypsies

The Sea Gypsies are nomadic people who live in a cluster of tropical islands in the Burmese archipelago and off the west coast of Thailand. A wandering water tribe, they learn to swim before they learn to walk, and live over half their lives in boats on the open sea, where they are often born and die. They survive by harvesting clams and sea chambers. Their children dive down, often thirty feet beneath the water's surface, and pluck up their food, including small morsels of marine life, and have done so for centuries. By learning to lower their heart rate, they can stay under water twice as long as most swimmers. They do this without any diving equipment. One tribe, the Sulu, dive over seventy-five feet for pearls.

But what distinguishes these children, for our purposes, is that they can see clearly at these great depths, without goggles. Most human beings cannot see clearly under water because as sunlight passes through water, it is bent, or “refracted,” so that light doesn't land where it should on the retina.

Anna Gislén, a Swedish researcher, studied the Sea Gypsies' ability to read placard under water and found that they were more than twice as skillful as European children. The Gypsies learned to control the shape of their lenses and, more significantly, to control the size of their pupils, constricting from 22 percent. This is a remarkable finding, because human pupils reflexively get larger under water, and pupil adjustment has been thought to be a fixed, innate reflex, controlled by the brain and nervous system.

This ability of the Sea Gypsies to see under water isn't the product of a unique genetic endowment. Gislén has since taught Swedish children to constrict their pupils to see under water – one more instance of the brain and nervous system showing unexpected training effects that alter what was thought to be a hardwired, unchangeable circuit.

The Sea Gypsies have survived using a combination of their experience of the sea and holistic perception. Illustration by Elena.

Cultural activities change brain structure

The Sea Gypsies's underwater sight is just one example of how cultural activities can change brain circuits, in this case leading to a new and seemingly impossible change in perception. Though the Gypsies' brain have yet to be scanned, we do have studies that show cultural activities changing brain structure. Music makes extraordinary demands on the brain. A pianist performing the eleventh variation of the Sixth Paganini Etude by Franz Liszt must play a staggering eighteen hundred notes per minute. Studies by Taub and others of musicians who play stringed instruments have shown that the more these musicians practice, the larger the brain maps for their active left hands become, and the neurons and maps that respond string timbers increase; in trumpeters the neurons and maps that respond to “brassy” sound enlarge. Brain imaging shows that musicians have several areas of their brains – the motor cortex and the cerebellum, among others – that differ from those of nonmusicians. Imaging also shows that musicians who begin playing before the age of seven have larger brain areas connecting the two hemispheres. 

Giorgio Vasari, the art historian, tells us that when Michelangelo painted the Sistine Chapel, he built a scaffold almost to the ceiling and painted for twenty months. As Vasari writes,“The work was executed in great discomfort, as Michelangelo had to stand with his head thrown back, and he so injured his eyesight that for several months he could only read and look at designs in that posture.” This may have been a case of his brain rewiring itself, to see only in the odd position that it had adapted itself to. Vasari's idea might seem incredible, but studies show that when people wear prism inversion glasses, which turn the world upside down, they find that, after a short while, their brain changes and their perceptual centers “flip”, so that they perceive the world right side up and even read books held upside down. When they take the glasses off, they see the world as though it were upside down, until they readapt, as Michelangelo did.

It is not just :highly cultured” activities that rewire the brain. Brain scans of London taxi drivers show that the more years a cabbie spends navigating London streets, the larger the volume of his hippocampus, that part of the brain that stores spatial representations. Even leisure activities change our brain; mediators and meditation teachers have a thicker insula, a part of the cortex activated by paying close attention.

The Sea Gypsies are an entire culture of hunter-gatherers on the open sea, all of whom share underwater sight. For Sea Gypsies it is seeing under water. For those of us living in the information age, signature activities include reading, writing, computer literacy, and using electronic media.

In all cultures members tend to share certain common activities, the “signature activities of a culture.” Signature activities differ from such universal human activities as seeing, hearing, and walking, which develop with minimal prompting and are shared by all humanity, even those rare people who have been raised outside culture. Signature activities requires training and cultural experience and lead to the development of a new, specially wired brain. Human beings did not evolve to see clearly under water = we left our “aquatic eyes” behind with scales and fins, when our ancestors emerged from the sea and evolved to see on land. Underwater sight is not the gift of evolution; the gift is brain plasticity, which allows us to adapt to a vast range of environments.

(The Brain That Changes Itself by Norman Doidge, M.D., excerpt).

The implosion of the media into us, affecting our brains, is not so obvious, but we have seen many examples in our lives. Photo by Elena.