Rhythm may be tied to language, other abilities

BOWLING GREEN, O.—When songwriter George Gershwin wrote “I got rhythm,” he may not have realized that not everyone can make that claim. New research by Bowling Green State University psychologist Dr. J. Devin McAuley may help to explain why some people “feel the beat” while others do not.

McAuley, an associate professor and director of the University's J.P. Scott Center for Neuroscience, Mind and Behavior, has received a two-year grant from the GRAMMY Foundation to study the neural bases of rhythm perception. He and Dr. Jessica Grahn of the University of Cambridge's Cognition and Brain Sciences Unit are conducting a study to learn which areas of the brain show activity when a beat is perceived, and then how these brain activity patterns may differ among individuals.

The results of their study, “Neural Correlates of Individual Differences in Rhythm Perception,” may have implications that extend beyond music. Other research has suggested a possible connection between beat perception and aspects of language development.

McAuley and Grahn's project was one of six research grants given this year by the foundation. The grants are funded in partnership with the National Academy of Recording Arts and Sciences, an organization of musicians, engineers, producers and recording professionals dedicated to improving the cultural condition and quality of life for music and its makers.

“The GRAMMY Foundation is an unusual opportunity for us,” McAuley said. “Combining behavioral work with brain imaging and mathematical modeling provides a powerful set of tools to investigate the neural basis of rhythm perception. The project offers a unique opportunity to address a number of provocative questions about rhythm perception in musicians and non-musicians.”

So far, about 40 subjects have been tested using functional magnetic resonance imaging, which shows “not just what the brain looks like, but also what areas of the brain are active when particular behavioral tasks are performed,” McAuley explained. Initial results, he said, suggest that the neural circuits involved in beat perception may be different from those involved in other aspects of timing, such as those used in anticipating the change in a traffic light.

The subjects represent “musically trained and non-trained individuals with a wide range of musical experience,” he said. Fitted with earphones, they listen to a sequence of tones while being asked to perform tempo-perception tasks in which they must judge whether the musical sequences they hear are slowing down or speeding up. “We're finding that individuals can experience the same stimulus but have opposite perceptions,” McAuley said.

Their responses allow the researchers to determine the ease with which the subjects perceive the beat. Some appear to readily pick it up, while for others it is difficult or even impossible, the early data show. Also, individuals appear to listen using two opposite techniques: “beat-based” or “interval-based,” which also seems to correlate to two theories about people's sense of timing, McAuley said.

People who easily identify the beat appear to be those who can also internally generate a rhythm, McAuley said. “They seem to feel it,” he observed.

The researchers will examine what drives the lack of beat perception in some individuals and whether the two listening modes engage distinct timing mechanisms that are localizable to different regions of the brain.

“It's exciting,” he said. “We're now using mathematical models to predict brain activity. These computational models can help quantify the subjects' perceptions.”

McAuley, whose research program investigates how humans and other animals time their behavior, said the new experiment began as “an accident in our lab.” He and a graduate student disagreed about whether a sequence of tones was slowing down.

“We were disagreeing about what we were hearing, and I realized that this disagreement might have important implications for understanding individual differences in music perception,” he recalled.

He gives credit to a then-undergraduate student in his lab, Deborah Frater, who followed up on these initial observations with a more formal study that she then presented at the University's undergraduate research conference in 2006.

McAuley, who has been on the BGSU faculty since 1999, received his Ph.D. in cognitive science and computer science from Indiana University, followed by two postdoctoral appointments, one at Ohio State University and the other at the University of Queensland, Brisbane, Australia. Along with former BGSU faculty member Dr. Kevin Pang, he is also in the fourth year of a five-year, $1 million grant from the National Institute on Aging to study the effects of aging on timing. He was named BGSU's Outstanding Young Scholar in 2004.

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(Posted May 01, 2007 )