Babies memorize grammatical relationships without sleep

From an early age, children learn how to name things and events, how to combine words according to the rules of the language. Scientists at the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) Leipzig and Humboldt-Universität zu Berlin found that even six-month-old babies store relationships between speech elements in their memories. Did.

Children are subconsciously using their native language long before they understand the rules of their native language and are able to form grammatically correct sentences. To do this, the infant’s brain must first detect regular relationships between speech elements and somehow store them in memory.

According to a recent study published in the journal Nature Communications, which begins already in the first year of life. Neuroscientists from Berlin, Leipzig, Lübeck and Tübingen have shown that infants from 6 months to her 8 months very quickly form memories of regular relationships between speech elements. This is true even if the speech elements are separated by another variable rather than directly following them. element.

In this study, researchers monitored the brain responses of 85 babies from monolingual German-speaking families while listening to short Italian sentences for 10 minutes each during the learning and subsequent testing phases. I measured. In learning sentences, the words sta and può always occur with the prescribed ending (–ando or –are) of the next verb (eg La sorella sta parlando or Il fratello può cantare.). The stem (e.g. Perl or Kant) varies.

About an hour later, during the testing phase, researchers presented babies with similar sentences. This time, we used both the correct combination of learning phases (sta … –ando and può … –are) and the incorrect inverse combination. (sta … –are and può … –ando). Half of the sentences contained old verb stems already heard during the learning stage, and the other half contained new verb stems that the baby had never heard before.

Also, previous baby studies have shown that memory for word meanings is highly dependent on sleep, so the learning phase times were scheduled according to the children’s individual sleep routines. The children took a nap between the learning and testing phases, and another group of children stayed up until the testing phase.

Babies’ brain responses during the testing phase showed clear differences between correct and incorrect combinations in both groups. This suggests that whether or not babies take a nap immediately after learning, the infant’s brain is able to memorize the relationships between speech elements, unlike memorizing word meanings. concluded that it is possible.

Two memory effects, equally seen in the sleep and awake groups, occurred not only in sentences with new verb stems, but also in sentences with old verb stems. This means that babies can generalize their knowledge and expect the correct elements of learned phonetic combinations even when they hear completely new verb stems.

“Our results demonstrate that 6-month-old children have memory mechanisms associated with grammar learning,” said Angela D. Friederici, senior author of the study and director of MPI CBS. Summarize. “Furthermore, they are the first to show that the earliest mechanisms of grammar learning differ from those of learning word meanings.”

But the baby’s brain response had a different effect. And this differed between the sleep and wake groups. The awake group showed very similar effects during the learning and testing phases, whereas the sleep group’s brain responses varied from the learning phase to the testing phase. “We believe that this new memory effect after sleep is due to newly formed memories during sleep,” explains Manuela Friedrich, the study’s first author.

“Response types suggest that memories evolve during sleep and that infant brains store regular relationships in new forms after naps. connections may be transferred to language regions of the brain during sleep and stored there as associated language units.

“Clearly, sleep influences how knowledge about language relationships is stored in memory,” says Manuela Friedrich. However, it can cause changes in the underlying nature of memory.”