Feeling the beat: movement influences infant rhythm perception

Rhythms are vital from the beginning of our lives. Consider that the first thing a fetus feels is his mother’s heartbeat. Later, upon developing ears, the baby hears the murmured voices of his parents. What is the response to rhythm? A kick or twist: in other words, movement.

Rhythm perception and movement response is a human’s first mode of communication and continues to develop as the person grows. New research by Jessica Phillips-Silver, a Carnegie Mellon alumna, has shown that movement is connected to beat perception and encoding. In other words, how you move is influenced by the rhythms you hear and remember.

Phillips-Silver, a PhD candidate at McMaster University in Hamilton, Ontario, tested her hypothesis with seven-month-old infants, exposing them to ambiguous beat patterns and bouncing them in various beat combinations. For example, some infants were bounced on every second beat and some on every third beat. Previous experiments had been done on adults, but one of the goals of this experiment was to determine “the multisensory experience of music and how that develops earlier in life,” Phillips-Silver said.

Infants were tested for their rhythmic preferences by exposing them to a variety of rhythm patterns. Based on how long the infants listened to the pattern before turning their heads away or getting distracted, Phillips-Silver could tell what they liked. “Infants listen to what they like more and what is familiar,” Phillips-Silver said. The infants consistently chose to listen longest to rhythm patterns that matched those patterns with which they had been physically bounced to.

To ensure that the infants were encoding beat perception based on sound and motion rather than learning the beat patterns by watching the researchers bounce with them, Phillips-Silver conducted another set of experiments similar to the previous ones, only without moving the infants at all. Instead, a researcher bounced in front of them to ambiguous beat patterns while the infants were held still. In these cases, the infants showed no preferences for any beat patterns. Phillips-Silver proved that observing movement does not reinforce the accents in the sound. “So what does it take to recreate in the mind the rhythm you heard and felt?” Phillips-Silver asked. “It requires subject movement.”

Phillips-Silver became highly interested in the connection between movement and rhythm perception as an undergraduate in the Bachelor of Humanities and Arts program. With a dual major in psychology and music, Phillips-Silver’s undergraduate work laid the foundation for her doctoral work. “My term paper went on to become my PhD thesis,” Phillips-Silver said.

Working with seven-month-olds became a personally interesting study for Phillips-Silver on how infants respond to music. “Babies giggle to the rhythm. They roll themselves, trying so hard to dance,” Phillips-Silver said. Her evidence on rhythm encoding in infants shows that humans must have an innate ability to respond to rhythm. The way people move shapes what they hear, and though this is a learned process that occurs early in life, skill in the area can be acquired with practice. “Hopeless cases are very very rare,” Phillips-Silver said. “All types of adults have been tested and even with naïve subjects, the effect was there. But cultures that do it more are better at it.”

Phillips-Silver also dispelled the myth that playing classical music for babies will make them more intelligent, saying that it “is not founded on credible scientific evidence.” However, music is emotionally and perceptually rich for babies and movement makes it richer due to the encoding that occurs in the brain. “Play whatever [to babies] you like,” Phillips-Silver said. “But move with it.”