The brain isn't hardwired to read—here's how we pull it off and why some are better at it than others

Experienced readers often find the act of reading to be effortless, but evolutionarily speaking, deciphering written language is not a skill that the brain is hardwired for. Instead, the brain must learn to read using systems that have evolved for other purposes. This is significant because variations in these preexisting systems may explain why some individuals find reading easier than others, as well as how individuals who are deaf, blind, or have dyslexia approach literacy in different ways.

In a new study published in Cerebral Cortex, researchers have delved into the relationship between an individual's reading abilities and their brain structure, with a focus on twins with varying degrees of genetic overlap. By comparing brain scans from the Human Connectome Project, a large study of healthy young adults, and assessing their performance on language tests, the researchers identified several brain areas that contribute to the skills necessary for reading.

One such area is a region adjacent to the primary auditory cortex at the top of the left temporal lobe, known as the medial belt area. This area is particularly adept at identifying slowly developing changes in sound, such as the different components of spoken syllables. Interestingly, a well-organized structure of nerve cells in this region is associated with better reading ability, and this organization may have a genetic component, suggesting that the organization of this perceptual system could influence the ease of learning to read.

Another crucial area is the dorsal temporal pole in the right anterior temporal lobe, which plays a role in recognizing written words in a manner similar to how we identify faces by their defining features. The size of this area is also linked with reading ability, and the relationship between this brain structure and reading skills appears to be genetically transmitted.

Finally, the left anterior temporal lobe, specifically the anterior middle temporal gyrus, is thought to connect word form and meaning. A larger size in this region is associated with improved deciphering of meaning, and it appears that this relationship is also genetically linked to reading ability. These findings shed light on the initial conditions for reading ability and the ways in which the brain learns to read, as well as the genetic factors that may influence these processes.