Even before they can crawl or speak, infants are essentially "wired" for music.

A new study reveals that humans enter the world with a built-in ability to anticipate musical beats, though the capacity to track a melody takes a bit more practice and time to develop.

The research, published Feb. 5 in PLOS Biology, explored whether musical aptitude is a behavior we are born with or one we learn. 

While previous studies have shown that as early as 35 weeks' gestation, fetuses react to sounds with changes in heart rate, scientists have struggled to understand exactly what newborns process when a song is played.

To learn more, investigators conducted an experiment with 49 sleeping newborns, all only two days old.

They were serenaded with piano pieces by Johann Sebastian Bach. Some were original melodies, while others were scrambled versions in which the pitches and note timings were shuffled, while the rhythm remained intact.

Using electroencephalography (EEG) to monitor brain activity, the team looked for signs of "neural surprise." This occurs when a brain anticipates one pattern but receives another.

The results showed that the babies' brains spiked with activity whenever the rhythm of the music changed unexpectedly. They showed no such reaction when the melody was altered.

"Our latest research shows that even our tiniest 2-day old listeners can anticipate rhythmic patterns, revealing that some key elements of musical perception are wired from birth," the authors noted in a news release.

The study was led by Roberta Bianco of the Italian Institute of Technology in Rome, along with investigators from the University of Pisa in Italy and others from institutions in Hungary and Germany.

This distinction suggests that humans have a "biological toolkit" for timing that exists from day one. 

In contrast, the ability to recognize a tune or a specific sequence of notes seems to be a skill that is acquired later in life through constant exposure to music and speech.

"There's a twist: melodic expectations — our ability to predict the flow of a tune — don't seem to be present yet," researchers explained. "This suggests that melody isn't innate but gradually learned through exposure. In other words, rhythm may be part of our biological toolkit, while melody is something we grow into."

Understanding these early auditory responses is more than just a curiosity: It helps biologists and doctors understand how the human sensory system matures. 

By pinpointing when babies begin to track melodies, scientists can better identify how the brain prepares for complex tasks like language and communication.

The authors concluded that, "future investigations should assess whether the observed dominance of rhythm over melody reflects state-dependent factors such as sleep or instead marks an early developmental bias that gradually shifts with experience toward the balanced sensitivity observed in adulthood."