Scientists find reading does the brain good

From a young age we are encouraged to read and are frequently told it is good for the brain. But what exactly does reading do to the brain? An international team of neuroscientists set out to answer this question and found that people who could read, regardless of whether they...

From a young age we are encouraged to read and are frequently told it is good for the brain. But what exactly does reading do to the brain? An international team of neuroscientists set out to answer this question and found that people who could read, regardless of whether they learnt as children or adults, exhibited more vigorous responses to written words in various areas of the brain. The research was recently published in the journal Science.

The scientists from Belgium, Brazil, France and Portugal, and led by cognitive neuroscientist Stanislas Dehaene of the Institut National de la Santé et de la Recherche Médicale (INSERM) in Gif-sur-Yvette, France, set out to discover whether literacy improves brain function and if it also entails losses. They measured the brain responses of 63 Portuguese and Brazilian participants to spoken and written language, visual faces, houses and various tools using functional MRI (magnetic resonance imaging). In total, 10 volunteers were illiterate, 22 became literate as adults and 31 had learnt to read in childhood.

The results showed that they all displayed more vigorous responses to written words in several areas of their brains which process what we see. In addition, in literate, but not illiterate, people, written words also triggered brain activity in parts of the left temporal lobe that respond to spoken language. According to the team, this suggests that reading uses brain circuits that evolved to support spoken language, a much older innovation in human communication. Reading is a relatively recent invention in human history; we have only been reading and writing for only about 5,000 years.

'Literacy, whether acquired in childhood or through adult classes, enhances brain responses in at least three distinct ways,' said the authors in their paper. They explained that it 'boosts the organisation of visual cortices', the portion of the brain that receives and processes impulses from the optic nerves. Literacy had this effect 'particularly by inducing an enhanced response to the known script at the VWFA [visual word form area] site in left occipito-temporal cortex and by augmenting early visual responses in occipital cortex, in a partially retinotopic manner', they pointed out.

Secondly, according to the team, 'literacy allows virtually the entire left-hemispheric spoken language network to be activated by written sentences. Thus reading, a late cultural invention, approaches the efficiency of the human species' most evolved communication channel, namely speech'.

Finally, they noted that their research proved that 'literacy refines spoken language processing by enhancing a phonological region, the planum temporale, and by making an orthographic code available in a top-down manner'.

There may be a downside to all this extra brain activity, however. The researchers found that in people who learnt to read early in life, a smaller region of the left occipital-temporal cortex responded to images of faces than in the illiterate volunteers.

'These largely positive changes should not hide that literacy, like other forms of expertise, also leads to cortical competition effects,' the authors noted. 'At the VWFA site, a significantly reduced activation was found for checkerboards and faces.' However, they said more research will be necessary to determine whether this actually causes our face-recognition abilities to suffer.

This is not the first time that the importance of reading for the brain has been highlighted. Last year, Manuel Carreiras from the Basque Center on Cognition, Brain and Language in San Sebastián in Spain found that the brains of adults who learned to read as adults were structurally different to those who could not read.

Countries

Belgium, Brazil, Spain, France, Portugal