Babies process words just like adults
Babies just over a year old are able to understand words just like adults, find researchers.
In a new study, specialized MRI and MEG imaging tests that look at the brain were used to see how babies respond to spoken words. Scientists from University of California, San Diego found they process words and not just sounds, much like adults, and in the same area of the brain as grown-ups.
Scientists used non-invasive MEG and MRI tests to view brain activity in 12 to 18 months old. MEG (magnetoencephalography) is a type of test that measures weak magnetic fields generated by electrical activity in the neurons of the brain.
Co-leader of the study, Katherine E. Travis, of the Department of Neurosciences and the Multimodal Imaging Laboratory, all at UC San Diego explains, “Babies are using the same brain mechanisms as adults to access the meaning of words from what is thought to be a mental 'database' of meanings, a database which is continually being updated right into adulthood.”
There have been several theories about how babies process language, one being that the brain evolves from infancy to adulthood, but begins with a primitive form of learning. Adults with frontotemporal lesions in the brain have difficulty processing language leading to speculation about language processing, but for infants, that part of the brain doesn’t seem critical.
One theory is that the difference between adults and babies is that a different area of the brain engages in infancy for language development - specifically, the right hemisphere and inferior frontal regions that become less dominant as babies mature, but the theory lacks evidence.
One way to observe how language is processed with the imaging techniques used by the scientists in the current study, which allowed the researchers to observe areas of the brain activated when a baby hears words. The scientists found out that babies understand the meaning of words, before they speak.
The researchers exposed the babies to sounds, pictures and words in the study. Some of the words were paired with acoustic sounds with no associative meaning. In the second part of the study, words were spoken and either matched or mismatched to pictures to see if babies really do understand the meaning of words.
Brain activity on the scans showed that babies knew the difference between words that did not match the pictures. The same brain response occurred in the babies as in adults, in the same left frontotemporal areas. The researchers confirmed the response was the same in adults shown pictures that did not match words.
When the scientists showed pictures of a ball for instance, and spoke the word, the same area of the brain used by adults was activated, showing babies do understand language and that they can process words.
Eric Halgren, PhD, professor of radiology in the School of Medicine says, “Our study shows that the neural machinery used by adults to understand words is already functional when words are first being learned. This basic process seems to embody the process whereby words are understood, as well as the context for learning new words.”
The findings show babies do understand words and process language just like adults. The scientists say their research results mean infants could be screened for language disabilities and autism at an early age.