Let’s hear it for the written word. Learning to read can have profound effects on the wiring of the adult brain, even in regions that aren’t usually associated with reading and writing.
That’s what researchers found when they taught a group of illiterate adults in rural India to read and write.
Michael Skeide and colleagues at the Max Planck Institute for Human Cognitive and Brain Science in Leipzig, Germany, wanted to study how culture changes the brain, so they focused on reading and writing. These cultural inventions have appeared only recently in our evolutionary history, so we haven’t had a chance to evolve specific genes for such skills.
The team recruited 30 people whose average age was about 31. Twenty-one were taught to read and write the Devanagari script, which is used in Hindi and other Indian languages, over six months. Nine people weren’t taught anything. All had their brains scanned before and after the six-month period.
By the end of the study, the team saw significant changes in the brains of the people who had learned to read and write. These individuals showed an increase in brain activity in the cortex, the outermost layer of the brain, which is involved in learning.
Learning to read also seemed to change brain regions that aren’t typically involved in reading, writing or learning. In particular, two regions deep in the brain appeared more active after training: portions of the thalamus and the brainstem.
These two regions are known to coordinate information from our senses and our movement, among other things. In those who had learned to read, both areas made stronger connections to the part of the brain that processes vision. The most dramatic changes were seen in those people who progressed the most in their reading and writing skills.
The brainstem and thalamus are also known to control attention, so this may also be enhanced by learning to read and write.
“This clearly shows that reading, which involves important cognitive processes, also involves the development of important sensorimotor skills, namely the need to finely control eye movements to scan the text lines and to [move the eyes] onto most informative parts of text,” said Gianluca Baldassarre of the Institute for Cognitive Sciences and Technologies in Rome.
Such changes are probably happening in children as they learn to read and write — possibly faster and more widely than was seen in the Indian adults — but no such studies have been done in children, says team member Falk Huettig of the Max Planck Institute for Psycholinguistics in Nijmegen, the Netherlands.
The findings might help shed light on dyslexia. In people with that condition, the structure and function of the thalamus can be different from what is typical. If the wiring of the thalamus can change with an intensive literacy course, it is possible that a lack of reading experience may explain these differences. The real cause of dyslexia may lie elsewhere, Huettig said.