Nina Kraus, a biologist at Northwestern University, has spent the better part of her professional career researching how sound affects the brain. What she’s found has important implications for how adults and children manage the sounds that envelop them. “Sound is invisible, but it’s a tremendously powerful force,” said Kraus. “For better or worse, it shapes your brain and how you learn.”
At Northwestern’s Auditory Neuroscience Lab, Kraus and colleagues measure how the brain responds when various sounds enter the ear. They’ve found that the brain reacts to sound in microseconds, and that brain waves closely resemble the sound waves. Making sense of sound is one of the most “computationally complex” functions of the brain, Kraus said, which explains why so many language and other disorders, including autism, reveal themselves in the way the brain processes sound. The way the brain responds to the “ingredients” of sound—pitching, timing and timbre—is a window into brain health and learning ability.
Kraus has learned that the brain’s response to sound in children as young as three is predictive of their ability to read. Her lab can also identify those children who are likely to struggle to read before those kids show signs of the language disorder. This kind of forecasting, Kraus said, could help schools and parents direct resources where they’re needed most. The brain changes in response to the sounds it’s processing; a three-year-old’s brain can adapt if the sound environment is altered.
Though every brain has its own fingerprint for processing sound, some sound environments are better than others at promoting learning. Parents and teachers should “encourage activities that promote sound-to-meaning development,” Kraus said. She offers several practical suggestions for creating that kind of space, whether at home or in school:
Reduce noise. Chronic background noise is associated with several auditory and learning problems: it contributes to “neural noise,” wherein brain neurons fire spontaneously in the absence of sound; it reduces the brain’s sensitivity to sound; and it slows auditory growth. A study of two different third grade classrooms--one overlooking a highway and the other beside a quiet field--found substantially better learning outcomes for kids in the quieter room. Because income and noise exposure are correlated—the lower the income, often, the louder the environment—finding pockets of quiet are that much more important for disadvantaged children. In school, this means building a quiet classroom, with acoustics in mind.