Athletes look different from non athletes. Similarly, the brains of literate people are different from those who do not read. The neural differences are not visible, of course. Yet, they have profound consequences for brain function, intelligence, and even longevity.
Word Recognition is Between Faces and Objects
The brains of literate people are profoundly different from those who do not learn to read. One intriguing phenomenon involves how reading comes to occupy its own space in the brain such that damage to this (in the left ventral occipital temporal region) selectively destroys the capacity to read (1, p. 260). Word recognition takes up residency in the region of the brain that sits between a face recognition area and an object recognition area.
In addition to such specialized changes that facilitate character, and word, recognition, there are many generalized changes in brain function. Literate people have a thicker corpus callosum, indicating that more information is crossing from one side of the brain to the other with the left hemisphere doing most of the language processing and the right hemisphere having an advantage in pattern recognition. Literate people have a broader pattern of brain activation in response to spoken words, suggesting that the verbal stimulus evokes a visual response. They also have longer verbal memories, presumably because words are processed more deeply, both by accessing different sensory modalities (visual as well as auditory) and also getting more attention in terms of their constituent sounds.
Literacy and Intelligence
Given these varied changes in brain function, it would be surprising if being able to read did not affect information processing capacity in a more generalized way.
Literate people ask more of their brains and get more in return. One finds that as countries become more economically developed, and as literacy increases, that IQ scores go up.
This is a complex relationship and there are many different factors that boost IQ scores as a country develops, including improved nutrition, better prenatal health, less low birth weight, smaller family size, and increased complexity of life in modern societies (2).
Given what we know about the impact of learning to read on the developing brain, it is plausible that at least some of the effect of rising intelligence (i. e., the Flynn effect) is attributable to literacy. One relevant piece of evidence is the strong correlation between IQ and years of education. The more time people spend in school, the more intelligent they become and this is not simply a self-selection effect where more intelligent children are more likely to complete high school and go to college (2).
Given that education has the potential to boost intelligence, it could be argued that a third-level education should be a civil right in developed countries that could afford it.
For the more hard-headed amongst us, it could be argued that inexpensive third-level education brings more than commensurate returns to nations willing to make this commitment. One thinks of Ireland that took this leap in the 1960's and rapidly moved from being one of the poorest countries in Europe to being one of the wealthiest. This argument is bolstered by evidence on the health benefits of literacy.
Literacy and Health
Apart from the economic advantages of higher education, research has shown that general health, and even length of life, increase with years of education in this country (3). This effect is not easily explained in terms of smoking, alcohol consumption, or other risk factors for reduced life expectancy.
The most plausible explanation has to do with functioning of the brain itself, particularly given that senile dementia is often a harbinger of death.
One of the biggest causes of dementia is poor functioning of capillaries in the brain so that neurons do not receive the nutrients they require for processing information effectively. Well-educated people likely make greater demands on their brains throughout life so that circulation in the brain is maintained at a high level, much as physical exercise boosts cardiovascular health..
Your Brain on Electronic Media?
Our brains have responded to textual information in ways that are overwhelmingly positive for health as well as intelligence. Researchers have often been a lot more negative in their assessment of what TV and the Internet do to us, and there is a lot of negativity about the alleged problems of electronic addictions to gaming and social media (4).
These fears are likely overdone. At the end of the day, the human brain has an insatiable thirst for information and slaking that thirst is beneficial for brain function, despite persistent nagging worries about new technologies.
1 Henrich, J. (2015). The secret of our success: How culture is driving human evolution domesticating our species and making us smarter. Princeton, NJ: Princeton university Press.
2 Barber, N. (2005b). Educational and ecological correlates of IQ: A cross-national investigation. Intelligence, 33, 273-284.
3 Molla, M. T., Madans, J. H., and Wagener, D. K. ( 2004). Differentials in adult mortality and activity limitation by years of education in the united states at the end of the 1990s. Population and Development Review. 30, 625-646.
4 Greenfield, S. (2015). Mind change: How digital technologies are leaving their mark on our brains. New York: Random House.