Good readers have different brains

Fewer people seem to be reading for enjoyment. Fifty percent of UK adults say they don’t read often, up from 42 percent in 2015, and almost one in four young people aged 16-24 say they’ve never been readers, according to research by The Reading Agency. So, what does this mean? Will choosing video over reading affect our brains or our evolution? What do the brains of regular readers look like? A new study by Mikael Roll, published in Neuroimage, has the answers.

Mikael Roll, Lund University analysed open-source data from more than 1,000 participants to discover that readers of varying abilities had distinct traits in brain anatomy.

A study found that people who are good at reading have differences in two areas of the brain’s left hemisphere, which are important for language. One area is the anterior part of the temporal lobe, which helps link sensory, visual, and motor information to understand word meanings. The other area is Heschl’s gyrus, which is part of the auditory cortex.

Better readers had a larger anterior temporal lobe on the left side, which helps with understanding words.

While reading is often thought of as a visual skill, the study shows that phonological awareness, the ability to connect sounds with letters, is also important for reading.

A thinner left Heschl’s gyrus has been linked to dyslexia, but the research shows that the thickness of the auditory cortex varies across the population, with a thicker cortex generally correlating with better reading ability.

Why size matters

Is thicker always better? Not necessarily when it comes to brain structure. The auditory cortex in most people has more myelin in the left hemisphere. Myelin is a fatty substance that speeds up nerve communication and helps separate brain cells from each other.

This isolation and faster communication in the left hemisphere are important for language processing. It allows us to quickly recognize categories, like whether a speaker says “d” or “t” in words like “dear” or “tear,” rather than focusing on the exact moment their vocal cords start vibrating.

According to the “balloon model” of brain growth, the extra myelin in the left hemisphere pushes out cortical areas, making them flatter but more spread out. So, while the left auditory cortex may be thicker in good readers, it is still thinner (but more extended) than the right cortex.

Recent research confirmed this, showing that the left hemisphere generally has larger but thinner cortical areas with more myelin.

So is thinner better, then? Again, the answer is no, not necessarily.

Complex abilities that require integrating information tend to benefit from a thicker cortex. The anterior temporal lobe with its complex way of integrating information is indeed the thickest structure of all cortical areas. An underlying mechanism might be the existence of more overlapping, interacting neurons which process information more holistically.

Phonology is a highly complex skill, where different sound and motor features are integrated into speech sounds. It appears to correlate with a thicker cortex in an area near the left Heschl’s gyrus. While it is unclear to what extent phonology is processed in Heschl’s gyrus, the fact that phoneticians often have multiple left Heschl’s gyri suggests it is linked to speech sounds.

Brain structure can reveal a lot about reading abilities. However, the brain is flexible and can change when we learn new skills or practice existing ones.

For example, young adults who studied language intensively saw an increase in cortical thickness in language-related areas. Similarly, reading likely influences the structure of the left Heschl’s gyrus and temporal pole.

So, if you want to keep your Heschl’s gyrus healthy, pick up a book and start reading.

Finally, it’s important to think about what might happen to us as a species if skills like reading become less valued. Our ability to understand the world and connect with others could weaken. In other words, enjoying a book in your favorite chair is not just personal – it’s beneficial for humanity.