A recent study shows that newborn infants are capable of beat induction, the detection of a regular pulse in an auditory signal, thus shedding some light on the debate over whether our understanding of music is innate or learned.
István Winkler at the Hungarian Academy of Sciences and colleagues from other European universities studied the reactions of 14 healthy sleeping babies less than 1 month old wearing caps with sensors that measured the electrical activity along their scalps.
The researchers played a sequence of percussive sounds, using snare drum, bass drum and hi-hat cymbal, and measured auditory event-related brain potentials, the electrical response to the sounds. Then they played a series of altered sequences of the sounds, omitting a single sound in different positions. Only one of the variant sequences violated the rhythmic structure—by leaving out the downbeat.
“If you set up a sequence that generates an expectation,” says Winkler, “then when that expectation is violated, it makes an error signal or a surprise signal [in the brain].” In adults this response is called mismatch negativity; it starts around age 13 or 14. Although babies do not have an exact analogue of this response, says Winkler, there are observable signals in newborns that have similar features.
When the sequence missing the downbeat was played, the newborns’ responses changed, suggesting they had developed an expectation for the onset of the beat. They did not respond this way when they heard the other variant sound patterns. Their research was reported online on Jan. 26 by the Proceedings of the National Academy of Sciences.
Innate or learned?
These results challenge the idea suggested by some researchers in the field that beat induction is learned in the first year of life from parents rocking their children or moving with them in a rhythmic way. Instead, say study researchers, the results support the view that beat perception is innate.
Laurel Trainor, director of the Institute for Music and the Mind at McMaster University in Hamilton, Ontario, who was not involved in the study, is more cautious about the second part of the conclusion. “This study can’t tell you that,” she says, “because infants get all kinds of prenatal experience with sound and rhythm. Their hearing is functioning at about six months’ gestation—they hear their mother’s heartbeat, and they also get concurrent movement and rhythm experience when the mother walks.” What the study results do suggest, she says, is that if beat induction is learned, it is learned prenatally.
Not just for music
Beat induction in newborns is not necessarily specific to music, Winkler says. It also is part of adapting to the rhythm of speech and other forms of communication. He and his colleagues next will study whether the capability for beat perception and rhythm comprehension in newborns can predict how well they communicate with their mothers or primary caretakers later in infancy, and whether newborns are capable of a more complex understanding of rhythm.