How the brain tackles reading

A new India-focused study provides fresh insights into the subject

One of India’s enduring failures, education, has meant that the country has, by far, the largest number of adult illiterates in the world.  In 1951, in the first post-Independence Census, literacy was just 18 per cent overall (male 27.2 per cent, female 8.9 per cent). By 1991, literacy had risen, to 52 per cent (male 64 per cent; female 39.3 per cent). By 2011, literacy was at 74 per cent (male 82 per cent; female 65.5 per cent). There are massive discrepancies between states, and between rural and urban areas and differences in per capita/ caste, community, etc. 

In 2014, Unesco estimated India had 287 million adult illiterates — over a third of the total world population of illiterates aged above 15.  Ironically, this gap has led to India being at the cutting edge of research into adult literacy. The Adult Literacy Mission hopes to impart “functional literacy” to 25 per cent of illiterates in the 25-35 age group. 

Reading is a very recent acquired skill in evolutionary terms. Areas of the brain, evolved for visual pattern-recognition, are activated to understand letters and involved in the mental translation from visual letters to spoken language.  

Many people have various learning difficulties that affect reading skills without impacting intelligence. Richard Branson, Walt Disney and Pablo Picasso were all dyslexic for instance, and had trouble recognising letters.  

A recent India-focused study on adult literacy provides new insights into how the brain tackles reading. The Max Planck Institute for Psycholinguistics, Nijmegen (Holland) worked with the Centre of Biomedical Research (CBMR), Lucknow, and the University of Hyderabad to study changes in the brain when illiterate adults learn to read. A group of eight scientists co-wrote a paper published in the peer-reviewed journal, Science Advances (http://advances.sciencemag.org/content/3/5/e1602612 ).

It was earlier assumed that learning to read triggered changes only in the outer layer of the brain, the cerebral cortex. But this study discovered learning to read leads to much deeper changes. Brain regions that are very old and located deeper inside such as the thalamus and the brainstem are changed. 

Interestingly, these regions of the brain are also present in other mammals and cognitive studies indicate baboons can distinguish words from jumbled letters and chimpanzees can sort numbers.  
 

The paper explains the study’s methodology and aims: “In a controlled longitudinal intervention study, we taught 21 illiterate Hindi-speaking adults (20 women, one male) how to read Devanagari script for six months. The goal was to compare changes in resting-state fMRI (functional magnetic resonance imaging) data before and after learning, of the sample taught to read, with those of a sample of nine Hindi-speaking illiterates (eight females, one male), who did not undergo such instruction. Participants were recruited from the same community in two villages of a rural area near Lucknow and matched for the most relevant cognitive, demographic, and socioeconomic variables.... The experimental and control groups are not statistically distinguishable before the training but there is a statistically significant difference after the training.”  

Translation: A sample of 21 adults were taught to read basic Hindi over six months. By the end of that period, they had the reading skills of an average bunch of Class I students. A control group of nine illiterates were also tracked. Both sets were drawn from the same community and closely matched in other respects. fMRI scans, which track brain activity by detecting changes in blood flows, were used to compare brains. 

Significant differences in their brains were seen after training. “Massive macroscopic functional reorganisation processes occurred in the mature human brain.” The timing of activity in the colliculi superiores, a part of the brainstem, and the pulvinar, located in the thalamus, matched with the timing of activity in the visual cortex as learners were taught aksharas. The study suggests that reading capability improved as activity across these areas became better aligned. 

The changes mapped offer clues about causes of reading disorders such as dyslexia and may thus help in tackling disabilities. The changes and the timing alignments also suggest how we attain fluency, reading speed and comprehension. 

One possible cause for dyslexia is speculated to be thalamus dysfunction. This study indicates that even a few months of reading seriously modifies the thalamus and that implies the causes may lie elsewhere, such as in problems with visual-processing. Follow-up studies tracking children from before they learn to read, through years of school may lead to more insights, according to Falk Huettig, who was a lead author. 

It is heartening to know that adults (mostly in their early 30s) could attain this level of functional literacy so quickly. One useful spin-off from the literacy mission could be the development of further insights of this nature.