Babies Process Language like an Adult

Babies, even those too young to talk, can understand many of the words that adults are saying and their brains process them in a grown-up way.

Combining the cutting-edge technologies of MRI and MEG, scientists at the University of California, San Diego show that babies just over a year old process words they hear with the same brain structures as adults, and in the same amount of time.

Moreover, the researchers found that babies were not merely processing the words as sounds, but were capable of grasping their meaning.

This study was jointly led by Eric Halgren, PhD, professor of radiology in the School of Medicine, Jeff Elman, PhD, professor of cognitive science in the Division of Social Sciences, and first author, Katherine E. Travis, of the Department of Neurosciences and the Multimodal Imaging Laboratory, all at UC San Diego. The work is published this week in the Oxford University Press journal Cerebral Cortex.

"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," said Travis.

Previously, many people thought infants might use an entirely different mechanism for learning words, and that learning began primitively and evolved into the process used by adults.

Determining the areas of the brain responsible for learning language, however, has been hampered by a lack of evidence showing where language is processed in the developing brain.

While lesions in two areas called Broca's and Wernicke's (frontotemporal) areas have long been known to be associated with loss of language skills in adults, such lesions in early childhood have little impact on language development.

To explain this discordance, some have proposed that the right hemisphere and inferior frontal regions are initially critical for language, and that classical language areas of adulthood become dominant only with increasing linguistic experience.

Alternatively, other theories have suggested that the plasticity of an infant's brain allows other regions to take over language-learning tasks if left frontotemporal regions are damaged at an early age.