In contrast, adults only recognise the same dependencies when asked to actively search for them.
The study by scientists at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig also highlights the important role of basic pitch discrimination abilities for early language development.
The speed and apparent ease with which young infants learn the basics of a language regularly astound parents and scientists alike.
Adults are usually assumed to have the edge in sophisticated language learning.
However, researchers have now found that when it comes to extracting complex rules from spoken language, a three-month-old outperforms adult learners.
The scientists played a stream of syllables to babies for 20 minutes, while measuring their brain responses using electroencephalography (EEG).
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Pairs of syllables appeared together, but were separated by a third syllable.
Jutta Mueller, first author of the study, stresses that "such dependencies between non-neighbouring elements are typical for natural languages and can be found in many grammatical constructions."
For instance, in the sentence "The boy always smiles", the third-person-suffix "s" of the verb is dependent on the noun "boy".
In the study, this was reflected in the use of combinations like "le" and "bu" in sequences like "le-wi-bu".
From time to time, however, combinations like "le-wi-to" would appear, in which one of the syllables was out of place.
"EEG measurements showed us that the babies recognised this rule violation", Mueller said.
Mueller and her colleagues conclude that, evidently, the automatic recognition ability is lost later on.
"What we found particularly interesting is that the small group of adults who did show evidence of rule learning also showed a stronger brain response to the pitch changes," she said in a statement.
These findings not only help understand how children manage to learn language so quickly during early development, but also point to a strong link between very basic auditory skills and sophisticated rule learning abilities.