Can Reading Improve Cognitive Function?

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For most of the period during which writing has existed, reading has been associated with intelligence, and for obvious reasons. Until relatively recently on the scale of human history, most of the global population was illiterate, and those who could read were generally wealthier groups with access to some form of formal education. As literacy became more necessary and education more available (and eventually compulsory) throughout most of the world, the ability to read has become commonplace, with estimates that around 87% of the global population has at least basic literacy. Yet despite the fact that reading is now a common skill, the stereotype of the bookish, glasses-wearing intellectual remains strong.

Now something unprecedented is happening in many developed countries: literacy scores are declining relative to educational attainment. At the same time, fewer people are reading for pleasure, with many pointing to digital transformation as the primary culprit. This invites the question: is reading ability just a reflection of educational level that is becoming less relevant as technology changes, or does reading actually affect cognitive function? Are we becoming dumber as a result of reading less? In this review, researchers try to untangle these effects and shed some light on whether reading is a practice that can boost cognitive health.

Readers Report Mental Health Benefits

Researchers started by discussing survey data concerning the relationship between leisure reading and various mental health characteristics. Readers generally report that reading improves their mental health, motivates them to be healthier, and a majority said that reading helped them feel less lonely during the Covid-19 pandemic.

Survey data like this has to be taken with a spoonful of salt as these are not controlled studies in which the effects of reading specifically can be isolated. It’s not hard to see how sitting still for an extended period of time and performing a task generally considered to be relaxing is likely to relieve stress and improve mental health, but this may not have anything to do with the actual reading process. The data in question also comes predominantly from surveys of regular readers, and so even if the self-reported benefits are real, they might not apply to less frequent readers.

Childhood Leisure Reading Is Associated With Cognitive Benefits

Next, the authors looked at some more concrete data that came from the Adolescent Brain Cognitive Development (ABCD) Study. This was a study that followed a sample of over 10,000 children from across the United States. They looked at when these children started reading for pleasure and what their academic performance and cognitive function was after 3 years of follow-up. They found that children who started reading for pleasure earlier experienced fewer mental health problems, were less stressed, concentrated better and had higher educational attainment in adolescence. They maintained healthier lifestyles, including less screen time and more sleep. They also showed improved cognitive function in multiple domains and even showed beneficial structural changes in their brains, such as larger cortical areas and regions linked to language and emotional regulation.

Once again, these findings need to be taken with a pinch of salt, as there’s plenty of room for confounding factors and reverse causation to explain these effects. Researchers did control for obvious confounders such better educated parents encouraging their children to read. Even then, one can’t rule out the possibility that children who are developing faster for whatever reason are reading earlier as a result, and not the other way around.

Reading In Adulthood Correlates With Lower Risk Of Cognitive Decline

There is a reasonable amount of evidence that reading is at least correlated with lower risk of cognitive decline and dementia in older adults. Several studies have found that adults in their 60s and 70s who read regularly were around 35% less likely to develop dementia within the next 5 years. Once again, reverse causation is an issue here because changes in the brain that lead to dementia can start to occur upwards of a decade before dementia is diagnosed, meaning that regular reading could simply be a sign of being cognitively healthy.

Similar correlations exist for cognitive function, with regular readers generally scoring higher in all cognitive tests. The same caveats about confounding factors and reverse causation apply, though reading frequency did appear to be more than just a reflection of educational level, as those with fewer years in education who read regularly still performed better than non-readers.

Reading Leads To Changes In Brain Structure

Next, researchers reviewed the evidence for the neural basis of reading skill. Unsurprisingly, the act of reading involves increased activity in multiple brain regions, most consistently in those involved in visual recognition, language processing and controlling attention. This brain activity was observed in both children and adults, but interestingly involved slightly different patterns of activity throughout different brain regions, which could suggest that reading pathways continue to be refined and optimised throughout life.

Repeated cognitive tasks are expected to lead to physical changes in brain structure, and evidence does indicate that children with better reading ability have denser, better organised white matter (which connects different regions of the brain together) and have more grey matter (the brain matter that actually processes information and is responsible for perception, decision making and so on). Importantly, these differences seem to be a consequence and not a cause of reading ability. An 8-week training program that managed to improve reading ability among dyslexic children was associated with a significant increase in grey matter volume, and those changes persisted after the training program ended. The study wasn’t perfect as there was no control group, so it is possible that not all the changes in brain structure were related to reading ability specifically – for example, they may have been related to increased social contact or just cognitively stimulating activity in general.

The idea that reading is important for brain development in children isn’t exactly revolutionary, but what about in adults whose brains are fully developed and have more limited ability to change? A similar study conducted in functionally illiterate adults found that literacy training was also associated with a significant increase in grey matter volume, in some cases growing to be not significantly different from literate controls (who began the study with more grey matter than illiterate adults).

What You Read Might Matter

Finally, authors discuss some brain imaging data to suggest that the brain responds differently to reading depending on the content of the text. Reading fiction, particularly passages containing social content, was found to activate brain networks involved in social cognition such as understanding how other people think and act. It is also important to point out a recurring theme throughout the research: children who read content they actually enjoyed generally achieved better literacy and reported more benefits than those who read by necessity. This could suggest that children may be better served by helping them to find reading material they actually like, rather than simply forcing them to read a particular piece of literature…

Putting It All Together

So, the available evidence all points to an association between reading – particularly reading fiction for pleasure – and improved cognitive function, mental health, and reduced risk of dementia. The fact that literacy rates are declining in some places is almost certainly a bad thing. However, proving that the benefits associated with literacy are a direct consequence of reading itself is challenging, not only because people who read regularly tend to be wealthier, better educated and so on, but also because any cognitively engaging activity would generally be expected to have some benefits for cognition. To prove that reading is uniquely beneficial, a study would need to compare the effects of a reading intervention to other similarly engaging activities. Such studies don’t appear to have been done yet.

With those caveats aside, it’s not unreasonable to suspect that reading probably does benefit the brain, even in adults. The brain responds and rewires itself in response to what we demand of it – the so-called ‘use it or lose it’ principal. Reading engages the brain in ways that other activities don’t, so it may well benefit the brain in ways other activities don’t. However, if you are a literate adult who simply doesn’t read for pleasure in your spare time, the existing evidence doesn’t guarantee that reading will benefit you more than whatever else you were previously doing. The evidence also doesn’t have much to say about how much reading is necessary. Becoming a ‘bookworm’ when you already read for pleasure now and again may not have any additional benefits – it could even be bad if you read all day instead of a diverse range of cognitive tasks and physical exercise.