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Imitation Instinct Is More Basic Than Just Flattery

Medical imaging device reveals that two areas of the brain are programmed for mimicry as a tool to develop motor, communication and social skills.

May 18, 2000|ROBERT LEE HOTZ | TIMES SCIENCE WRITER

Simon says: Walk my walk.

Simon says: Talk my talk.

Simon says: Imitate.

Such copycat games of follow the leader, dependent on matching the actions of others, are the stuff of childhood afternoons and nursery school play.

Now, research also reveals that they are incorporated into the bedrock of the brain itself as an important natural tool for development and learning. Indeed, at the core of what it means to be human is a powerful instinct for imitation that dwarfs the aping abilities of other primates.

In its very cells and synapses, the brain is built to imitate, an international team of researchers has discovered.

Using a powerful medical imaging device to study the mind at work, UCLA neuroscientist Marco Iacoboni at the university's brain mapping division, working with colleagues in Italy and Germany, recently identified special areas of the brain involved in the act of imitation. To catch the copycat brain in the act, they took unique functional magnetic resonance images (fMRI), which capture the high-speed ebb and flow of enriched blood to active neural circuits.

They found that two areas of the brain appear to respond when we watch someone perform an action and when we perform the same action ourselves. The active neural circuits reveal the essence of mimicry.

Their work shows for the first time the neural anatomy of a crucial technique for picking up important motor, communication and social skills, several experts said.

"These findings are part of a revolutionary new understanding that thought and action are inseparable," said psychologist and computer theorist Michael Arbib, director of the USC Brain Project. They "provide a bridge from thought and action to the crucial role of imitation in our social behavior."

Imitation Is a Strong Instinct

So often, when we find ourselves on unfamiliar ground--from trying to master new dance steps or deciding which fork to use at a formal dinner, to learning the pronunciation of strange words--we learn by watching others for cues, then follow their lead. When we do so, whether as faddish followers of fashion or lip-sync stars, we rely on a powerful, instinctive talent for imitation.

"Even at birth we can imitate," said Iacoboni. "We have this built-in mechanism that allows us to imitate both movements and facial expressions we see in other people.

"The same regions of the brain that send commands to our muscles when we act also seem able to recognize the same action when performed by others," he said. "We believe that this brain mechanism allows us to understand the intentions of others."

Once researchers better understand the neural anatomy of learning, they hope to use those insights to create more effective rehabilitation techniques for people recovering from brain injuries. Eventually, they could also lead to more effective classroom teaching techniques.

"There is a tremendous amount of interest in the idea that you can understand better ways to teach by understanding how the brain is set up to learn," said John C. Mazziotta, director of UCLA's brain mapping center at the School of Medicine.

As a basic neural process, imitation itself may be as old as monkey see and monkey do.

Recent studies with macaques have shown that other primates have special "mirror" neurons in some parts of the brain that become active when matching another monkey's behavior. The neurons were detected in an area of the primate pre-motor cortex that fired when a monkey grasped an object and also when it saw another monkey do the same thing.

"It was a very important question--to see if there is [the same] mirror activity in the human brain, and, if there is, where it is located," Iacoboni said.

Identifying the copycat circuits in the human brain turned out to be as simple as lifting a finger.

To see if imitation was embodied in the human brain, Iacoboni, working with UCLA neuroscientists Mazziotta and Roger P. Woods, conducted a series of experiments in which volunteers were asked to perform a series of simple hand gestures while their brains were monitored in an fMRI scanner.

A Random Hand Points the Way

The volunteers were put through three variations of the test: They first were shown photographs of a hand randomly lifting its index or middle finger, then asked to match the gesture in sequence, and, finally, to look at abstract graphic images that just suggested the gesture. The experiment was kept as simple as possible to minimize unrelated brain activity.

By monitoring millisecond by millisecond changes in neural blood flow, the scanner recorded which parts of the brain were most active during each phase of the experiment.

Two areas became especially active--a portion of the right parietal cortex involved with precise physical movement, and a region of the brain called Broca's area, a key language center that may be involved in planning the goal of the physical movement.

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