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A universal sign of motherhood is the lullaby. The world over, mothers sing to their babies, whether Twinkle Twinkle Little Star, their favouritetunefrom the radio, or evenrandom notes. This universality creates the simple lullaby a fantastic window tothe human mind. In a new study, cognitive neuroscientists discovered that lullabies soothe both mothers and infantssimultaneously, while playsongs increase babies' attention and displays of positive emotion toward their mothers.

"Music and rhythm are human universals but do not appear to be shared by most other species," says Jessica Grahn of the University of Western Ontario who is chairing the CNS session on musical rhythm and who co-authored a new study of live music and brain rhythms.

Music for Mother and baby

While working in a daycare one summer as an undergraduate student, Cirelli was at a playground when a 2-year-old girl asked her for assistance down the slide.

The rest of the toddlers saw this, looked at each other, and excitedly ran over to line up and wait for their turn. "I was amazed at the intricacy of their social perception with an age where they can not even tell us exactly what they are thinking," she explains.

The participating mothers repeatedly sang Twinkle Twinkle to their babies who were sitting in a highchair facing them. The mothers alternated between singing in a playful way or a soothing manner. At the same time, researchers were tracking the mothers' and infants' arousal responses, measured through skin conductance and behavior. "When we are excited or stressed, stimulation levels grow," Cirelli explains. "When we're calm, they fall."

The researchers found that the moms' arousal levels were higher during lively compared to soothing tune. And they found coordinated declines in stimulation for the mothers and infants as the soothing tunes progressed. In the lively states, the infants' arousal levels remained stable and their attention to mother and displays of positive emotion increased. "The findings show the behavioral and physiological changes by mother and baby to various song styles"

This study builds on a growing body of work about the social implications of musical engagement with others. Cirelli points to past studies showing that when people move together in synchrony, they feel socially connected and are later more likely to help and cooperate with one another. And in a study of toddlers, she and colleagues had similar findings: 14-month-olds who bounced synchronously with unfamiliar adults helped those adults substantially more by retrieving dropped objects than those who bounced with them asynchronously. "Music is a tool that we can use to bring people together, and this starts in infancy."

Music for a live audience

Despite being able to listen to music from virtually anywhere in modern times, people will still pay hundreds of dollars for the opportunity attend a live musical performance. Why? This question helps drive forward the work of Grahn and Molly Henry, both of the University of Ontario.

In new work she will be presenting at the CNS meeting today, Henry used the LIVELab at McMaster University to test how the presence of live performers and an audience changes the experience of concert-goers at a neural level. Specifically, she and colleagues looked at brain rhythm synchronization.

A live band played in front of 80 people, 20 of whom were having their brain activity recorded with EEG. They then compared those EEG measurements to those in two other conditions: one, in which 20 audience members were watching a recording of the first concert on a large movie screen with audio identical to the live concert; and another in which 20 participants in small groups of 2 were seated apart while they observed the recorded musical performance. "Thus, we manipulated the presence of the actors while maintaining audience context mended," the authors explain.

They found that audience members' brain waves were synchronized with each other whenever the actors were present. Moreover, people whose mind rhythms were synched up with other audience members enjoyed the concert more and felt more attached to the actors.

"I was extremely excited to see that across the live audience, brain rhythms were synchronized in exactly the frequency range that corresponds to the 'beat' of the music, so it looks as if the beat is driving audience brain rhythms," Henry states) "That may seem common sense, but it's really something. These are novel findings in the context of live music listening that are providing insights into the more social side of music listening."

Music for the future

Moving forward, Henry states the largestbarrier for analyzing musical rhythm is that "there's so much other stuff tied up in the experience of music and rhythm listening or performing. Music makes us want to move, it elicits emotions, it triggers memories." Teasing apart these influences will call for creative stimulation and experimental design combined with integration of converging evidence across lots of different studies.

In the meantime, Grahn states: "We are seeing relationships between rhythm and language abilities, attention, development, hearing acuity, and even social interactions. Every sensation we have or action we make on the world unfolds over time, and we are now beginning to understand why humans are sensitive to certain types of patterns in time, but not others." Understanding these patterns will inform not only basic science, she states, but also potential music-driven therapies for patients suffering from neurodegenerative diseases.

 

Materials provided by Cognitive Neuroscience Society.

 

Article bySylvester Dean