New research shows that when adults learn to read for the first time, the changes that occur in their brain are not limited to the outer layer of the brain, the cortex, but extends to deep brain structures in the thalamus and the brainstem. This was observed in illiterate Indian women who learned how to read and write for six months. An international research team led by the Max Planck Institute (MPI) for Psycholinguistics and the MPI for Human Cognitive and Brain Sciences published the results in Science Advances. Below is their press release.
Large-scale study with illiterates in India
The interdisciplinary research team obtained these findings in India, a country with an illiteracy rate of about 39 percent. Poverty still limits access to education in some parts of India, especially for women. Therefore, in this study, nearly all participants were women in their thirties. At the beginning of the training, the majority of them could not decipher a single written word of their mother tongue Hindi. Hindi, one of the official languages of India, is based on Devanagari, a scripture with complex characters describing whole syllables or words rather than single letters.
Participants reached a level comparable to a first-grader after only six months of reading training. “This growth of knowledge is remarkable”, says project leader Huettig. “While it is quite difficult for us to learn a new language, it appears to be much easier for us to learn to read. The adult brain proves to be astonishingly flexible.” In principle, this study could also have taken place in Europe. Yet illiteracy is regarded as such a taboo in the West that it would have been immensely difficult to find volunteers to take part. Nevertheless, even in India where the ability to read and write is strongly connected to social class, the project was a tremendous challenge. The scientists recruited volunteers from the same social class in two villages in Northern India to make sure that social factors could not influence the findings. Brain scans were performed in the city of Lucknow, a three hours taxi ride away from participants’ homes.
A new view on dyslexia
The impressive learning achievements of the volunteers do not only provide hope for adult illiterates, they also shed new light on the possible cause of reading disorders such as dyslexia. One possible cause for the basic deficits observed in people with dyslexia has previously been attributed to dysfunctions of the thalamus. “Since we found out that only a few months of reading training can modify the thalamus fundamentally, we have to scrutinise this hypothesis”, neuroscientist Skeide explains. It could also be that affected people show different brain activity in the thalamus just because their visual system is less well trained than that of experienced readers. This means that these abnormalities can only be considered an innate cause of dyslexia if they show up prior to schooling. “That’s why only studies that assess children before they start to learn to read and follow them up for several years can bring clarity about the origins of reading disorders”, Huettig adds.