There are lots of wheels turning inside little minds long before babies have the words to express themselves—just ask any parent who has watched their baby process something new.

Now a study published this month in the journal Science proves just how complicated the inner workings of babies’ brains can be. It goes against some long-held expert opinions that language and the abilities to reason are linked by demonstrating that babies as young as 12 months have a mature process of elimination skills.

For the study, authors from several European institutions performed a test with 48 babies aged 12 to 18 months to gauge their “disjunctive syllogism” abilities. This is a form of logical reasoning that enables them to accept “if only A or B can be true, and A is false, then B must be true.”

To do this, researchers had the babies watch animations featuring two distinct objects, such as a dinosaur and flower. Then the objects disappear behind a barrier before a cup scoops up one of them in plain sight. The barrier then disappears, which should reveal the other object, right? Well, to prove their the theory, the first object (that was scooped up by the cup) is sometimes still in its place.

The little smarty-pants weren’t fooled, as they indicated with their sight patterns that this wasn’t what they expected to happen.

“Our results indicate that the acquisition of logical vocabulary might not be the source of the most fundamental logical building blocks in the mind,” says lead study author Nicoló Cesana-Arlotti, a postdoctoral fellow in the Department Psychological and Brain Sciences at Johns Hopkins University.

In other words, just because your baby can't talk, it doesn't mean he can't be logical. Which is pretty amazing because, “To our knowledge, nobody has ever directly documented logical reasoning in 12-month-old infants before.”

In an accompanying analysis of the research for Science, Johns Hopkins psychologist and reason researcher Justin Halberda says the findings conflict some traditional wisdom.

“I think many people would say that most of their reasoning happens when they are silently talking to themselves in their heads,” says Halberda, who was not involved with the research. “What this new study reveals is that pre-verbal infants are also working through this same type of serial reasoning, and doing so before robust language abilities have been mastered.”

The findings have potentially significant implications for health experts who may be able to use them in determining intellectual delays among children sooner—and are therefore able to begin special education programs earlier.

This comes a few months after some amazing research that shows babies as young as 6 months old are already connecting related words, which lay the foundation for their own language skills.

For parents, this is all more proof that our babies can make significant logical connections long before they’re able to carry on conversations. So just be warned next time you try to pull one over on your little Einstein.

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