Music and the Pregnant Pause

Aug. 8, 2007 — -- Scientists have tapped into the universal language of music to open the secrets of the brain, and they have discovered something ancient composers knew instinctively hundreds of years ago -- the value of silence.

The latest research from the Stanford University School of Medicine shows that a few seconds of silence during a musical piece trigger responses in the brain that allow listeners to break the piece into digestible chunks so they can remember it. A brief pause also triggers a listener's ability to pay close attention and anticipate what will come next.

"That's really the surprising aspect of our study," said Vinod Menon, associate professor of psychiatry and behavioral sciences at Stanford and senior author of the study, published in the current issue of the journal Neuron.

Brain scans were conducted on 18 people as they listened to a symphony by an obscure 18th-century composer, William Boyce. The scans revealed that it's really the pauses in the music, not the music itself, that fire up the parts of the brain that allow people to record and anticipate the experience. So the most important cognitive activity occurred when seemingly nothing was going on. The rest of the time the brain was free to wander, as it so often does while listening to music.

The researchers would not have had the same result if they had picked familiar tunes, or pieces that were well known by the participants in the study, because they would already know what comes next and the pauses would have had little effect.

Music, in this research, is the vehicle, not the target. Every tribe has had its music, probably from very early in human history, so it is truly a universal experience. Thus, many researchers have turned to music to see what they can learn about the human brain, and they have learned much. The most common tool is functional magnetic resonance imaging, a noninvasive procedure that allows researchers to monitor the flow of blood in the brain, thus revealing which areas of the brain respond to various kinds of stimuli.

Menon's team, which has been studying music and the brain for several years, previously demonstrated that music increases the connectivity between areas of the brain that are involved in the brain's reward system. Other researchers have found that music enhances the ability to learn, and to remember, and it can even tune up the auditory system.

It's interesting that science is finally catching up with composers and writers and other creative persons who have known all along that timing, and an unanticipated sound, can be extremely important. No one knows that better than a comedian. The master of good timing was Bob Hope, who knew that a brief pause before the punch line could trigger anticipation, and robust laughter.

Why? Menon said his team's research shows "there's a system in place that detects significant events and sets up expectation of what's going to happen next. It primes the rest of the brain for action."

That can be a tear, following a moving piece, or a laugh, following an unanticipated punch line.

While in this research it was the pause that proved significant, Menon said any significant change in the composition, such as tempo, an unexpected chord or a sudden change in pitch, would have had a similar effect. It would serve as a marker, allowing the brain to record that section and anticipate the next, since it obviously isn't possible for the listener to remember the entire symphony as a single unit. Scientists call it "event segmentations."

Eighteen persons (10 men and eight women) who had no formal training in music took part in the study. Boyce's compositions were used for the experiment because they comprise well-defined movements, so a brief pause would signal a change in the piece even for people with little musical experience. The participants listened to the music through earphones while they were inside the noisy scanner, and all of them showed some effect from the pauses.

"The signal during these pauses was very, very strong," Menon said. Analysis of 10 seconds surrounding the pause showed activity in two brain regions, the ventral region of the prefrontal cortex, which triggered activity in the second area, the dorsal region. That is considered significant because the active regions were in the right hemisphere of the brain, which is believed to be involved in processing music.

The differences in activity between the right and left sides of the brain were described as "striking" by the research team, which includes several musicians, Devarajan Sridharan, Chris H. Chafe and Jonathan Berger of Stanford, and Daniel J. Levitin of McGill University in Montreal.

Perhaps surprisingly, there was a physical, not just a mental, response among the participants.

"It wasn't just a brain signal," Menon said. "There was also a physiological signal. The heart rate became more variable (during the pause). So there's something interesting happening."

The finding has applications far beyond the field of music, he added. It helps explain, for example, how we can somehow listen to one conversation in a crowded room of gabbers. Slight changes in the other person's voice allow a listener to break down the conversation into understandable "chunks," as Menon put it, and focus attention on that one person.

It's also why the pregnant pause is so useful to comedians and composers, as well as the person you're trying to listen to in a noisy room.

Lee Dye is a former science writer for the Los Angeles Times. He now lives in Juneau, Alaska.