Trying harder at learning a new language can actually make it harder to master, according to new research. In fact, children are better able to master a foreign language compared to adults.

According to the National Council of State Supervisors for Languages, learning a second language helps Americans better compete in a global marketplace, as well as create a more informed citizenry.

A “sensitive period” for learning a new language typically ends at adolescence. Prior to this threshold, the young brain of children features neural circuits that are able to identify sounds and develop a set of rules for building words and sentences from these sounds. In adulthood, these language structures have already been established, which makes it harder to build a new one to learn a different language.

A new study led by Amy Finn, a postdoc at MIT’s McGovern Institute for Brain Research, discovered evidence to suggest that the more highly developed cognitive skills of adults can get in the way of learning a foreign language. The harder an adult tries, the worse they are at distinguishing the morphology of the language.

“We found that effort helps you in most situations, for things like figuring out what the units of language that you need to know are, and basic ordering of elements. But when trying to learn morphology, at least in this artificial language we created, it’s actually worse when you try,” said Finn in a statement.

The findings suggest that learning a new language involves the use of procedural memory or declarative memory. Facts and knowledge are stored under declarative memory, which is useful for learning specific grammar rules. The tasks we perform without conscious awareness of how they were learned are stored under procedural memory.

The researchers found that it’s the procedural memory that makes it easier to learn a new language, and declarative memory actually hinders this learning process.