Contrary to popular belief, learning to read is not natural, and there is no area of our brains that comes pre-wired this function. Our brains are, however, designed for language. The ability to hear, produce, and understand spoken language is biologically primary, meaning this function doesn't require formal instruction to be acquired. Conversely, reading is a biologically secondary skill; there is no 'reading center' in the brain at birth (Geary 2008; Wolf 2007). We develop language skills simply through immersion in spoken language. There are specific areas of our brains pre-wired for language functions. For example, Broca's area controls controls our ability to produce spoken language, whereas Wernicke's area controls our ability to understand spoken language. Located in the temporal lobe, the auditory cortext analyzes the language we hear. Our brains also have specific areas dedicated to interpreting visiual and motor aspects of our environment. Each of these areas plays a critical role in learning to read although they were never designed for reading. Through instruction we rewire our brains to make connections between the visual, auditory, and motor regions of our brains to make sense of those squiggly shapes and lines we call letters.

Researchers have long studied reading in an attempt to understand how reading sworks in the brain, why some students con do it well, and why others struggle. Before the advent of technologies such as PET scans, MRIs, and fMRIs, our understanding of the brain was very rudimentary and based primarily on observations. Since there was no way to look into the brain, scientists had to rely on observations of patients with brain injuries to learn which areas of the brain controlled specific functions. They would collect data on functions that were lost as a result of the brain injury and post-mortem were able to them identify the specific regions of the brain that had been impacted. 

It wasn't until the 1980s that technology had advanced enough for scientists to be able to "see" the brain working in real time through PET scans, or Positron Emission Tomography (Posner and Raichle 1994). Volunteers were injected with or drank a radioactive dye that would then "light up" when the test subjects conducted reading tasks. This was able to give scientists a view into the specific regions of the brain involved in reading. However, due to the use of radioactive materials, these types of studies were not appropriate for children or safe for replication on a broader scale. Another type of technology used is known as MEG, or Magnetoencephalography. While PET scans targeted blood flow, MEG analyzed the magnetic fields produced as a result of neuronal activity, and these scans could collect data at a much faster rate- within milliseconds. These studies allowed scientists to determine the timing of when and where information is processed when reading (Posner and Raichle 1994). The real breakthrough came with the use of fMRIs, or Functional MRIs, to track reading as it happens in the brain and was also safe enough to be used with children. fMRI imaging studies revealed that skilled readers activate a highly efficient circuit in the left hemisphere, connecting the visual, phonological, and semantic processors. In contrast, struggling readers often show hypo-activation, or under-activity, in these left-hemisphere areas and often attempt to compensate by over-activating regions in the right hemisphere—a much slower and less efficient pathway for literacy (Shaywitz 2003; Eden 2004).

Many researchers such as Sally and Bennet Schaywitz, Maryanne Wolfe, and Guinevere Eden were pioneers in using these types of research to better understand those who struggled with reading, particularly those with dyslexia. Stanislas Dehaene’s (2009) pivotal research identified the Visual Word Form Area (VWFA), or the 'Brain’s Letterbox'. Through neuronal recycling, the brain repurposes neurons originally designed for recognizing faces and objects to instead recognize letter strings. Most importantly, Bruce McCandliss (2015) demonstrated that only when instruction focuses on letter-sound correspondences (phonics) does the brain successfully build these left-hemisphere pathways. Instructional methods that rely on whole-word memorization misdirect brain activity to the right hemisphere, failing to build the neural 'highway' required for fluent reading.

Watch the video below to hear Dr. Dehaene explain his research findings on how learning to read changes our brains.