Once you were a child who took pains to “sound out” each letter as a way to comprehend an entire word. Now you are an adult who is breezing through these sentences without effort yet still understanding the meaning of each and every word. What changed? According to a team of researchers at Georgetown University Medical Center, neurons in one area of your brain are now responding to complete words, not pieces of them or individual letters. In fact, when you look at any familiar word, the visual word form area of your brain sees it as a complete picture, not a group of letters to be processed.
These new findings, the researchers say, not only show how the brain processes words, they also offer insight helpful to people with reading disabilities.
To begin the study, co-authors Dr. Maximilian Riesenhuber and Dr. Laurie Glezer asked 25 adults to learn a set of 150 nonsense words. However, both before and after this training, the researchers peeked into the brains of volunteers by using an scanner. Specifically, they used fMRI-rapid adaptation, a technique that traces brain plasticity as it happens. After first observing the impact made by nonsense words, the researchers could see changes as they occurred in the brain while the volunteers learned the made-up words.
Visual Word Form Area
Our neurons respond differently to real words than to nonsense words, the researchers explained. In fact, one small area of the brain is precisely wired to recognize not parts of words but complete words. Neurons in a small brain area, called the visual word form area, remember how the whole word looks.
It does this by “using what could be called a visual dictionary," said Riesenhuber, who is leader of GUMC's Laboratory for Computational Cognitive Neuroscience. Very simply, our visual word form area recognizes familiar words as distinct blocks. The visual word form area is located in the left side of the visual cortex, opposite from the fusiform face area (which remembers faces) on the right. They sit, then, like mirror images in opposite positions within your brain.
"One area is selective for a whole face, allowing us to quickly recognize people, and the other is selective for a whole word, which helps us read quickly," Riesenhuber said in a press release. During the study, then, the neurons in the visual word form area began to respond to the learned nonsense words like they were real words.
"The visual word form area does not care how the word sounds, just how the letters of the word look together," Riesenhuber said. In fact, after publishing a previous study about this, a number of people with reading difficulties contacted him to report how learning words as visual objects helped them learn to read. More proof that understanding the brain helps us get the most out of it.
Source: Glezer LS, Kim J, Rule J, et al. Adding words to the brain's visual dictionary: Novel Word Learning Selectively Sharpens Orthographic Representations in the VWFA, Journal of Neuroscience. 2015.