Repeat after me: imitation is the sincerest form of perception.

Enemy soldiers captured Army Private First Class Jessica Lynch when her convoy got lost during the opening days of the Iraq war. But her destiny took a dramatic turn for the better when an Iraqi man whom she had never met saw one of the captors slap Lynch's face twice as she lay wounded in a hospital. In news accounts, the Iraqi man, a lawyer, recounted the scene by motioning with his right hand as if he were slapping someone. He said, "My heart cut," an expression comparable to "My heart stopped." At that point, he put his hand over his chest and grimaced.

After seeing Lynch, the 32-year-old man walked 6 miles to find U.S. Marines and tell them about the female prisoner. At their request, he returned to the hospital to gather information on its layout and the number of Iraqi soldiers in the building. After the man returned and drew maps of the hospital and its vicinity for the Marines, U.S. forces rescued Lynch.

This tale of bravery hinged on the Iraqi man's visceral, emotional adoption of the vulnerable prisoner's perspective. Instances of one person participating in another's mental and physical experience dramatically. Researchers are now trying to understand how perspective shifts of this kind, in people and perhaps in other animals as well, grow out of an apparently brain-based aptitude for copycatting.

There's nothing new about the scientific appeal of this issue. More than a century ago, Charles Darwin wrote detailed accounts of mimicry in animals and theorized that many creatures respond to the emotional states of their comrades. In 1903, German psychologist Theodore Lipps wined the term that translates as "emphathy" and literally means "feeling into." Lipps theorized that the perception of another individual's emotional expression or gesture automatically activates the same emotion in the perceiver.

Current research efforts focus on imitation--an individual's recreation of another's actions--as the backbone of empathy, the capacity to infer whet others are feeling or thinking. This line of research, traces its origins to surprising reports in the 1970s that even some newborn babies can mimic various facial movements. Investigators received another jolt in 1996, with the discovery of so-called mirror neurons in the brains of macaque monkeys. These cells emit comparable electrical signals when monkeys perform an action and when they observe another animal execute the same action.

The existence of both infant end neural mimicry fueled the conviction that the brain contains a single code for perceiving the world and acting in it. This idea also has a long history, although it has usually taken a backseat to the notion that perceptions stimulate thoughts, which then guide behavior in a chain reaction of separate processes.

Much of the latest thinking on imitation gets aired in The Imitative Mind (A.N. Meltzoff and W. Prinz, editors, Cambridge University Press, 2002). New findings were also presented on March 31 at the annual meeting of the Cognitive Neuroscience Society in New York.

"We're reviving some old concepts about the mind with modern neuroscience," says Marco Iacoboni of the University of California, Los Angeles (UCLA). "There's much we don't know, but empathy seems to involve the mirroring of another person's emotional responses in one's own brain."

THEY'RE WATCHING Babies aren't big empathizers. Yet when it comes to imitating others, they hit the ground running.

A 1977 study directed by psychologist Andrew N. Meltzoff of the University of Washington in Seattle found that 2-to-3-week-old infants avidly reproduced an adult's facial movements, such as sticking out their tongues and opening their lips. Meltzoff has since documented infant imitation of abroad range of acts, including band gestures, eye blinking, and head movements. Even some newborns, ranging in age from 42 minutes to 3 days, have aped adults' faces in his experiments.

A baby's mimicry of, say, an adult sticking out his tongue to one side usually begins with halting tongue movements. Nevertheless, the desired tongue protrusion gradually emerges, even without any adult encouragement.

Infants rapidly move on to imitate all sorts of novel acts, such as touching one's forehead to a box that then lights up. Junior imitators also pay particularly close attention to the results rather than the details of actions. For instance, after watching a woman perform the forehead-to-box routine while holding a blanket around her shoulders, most 14-month-olds light the box by touching it with their hands (SN: 2/28/02, p. 125). These youngsters apparently figure that the woman had her own reason for not using her hands on the box and opt for the simpler approach.

"Babies are interpreters of our actions," Meltzoff says. "Even imitation by 1-month-old infants is voluntary and goal-directed." It shocks parents when they realize that "the babies are watching us," he notes.

Meltzoff theorizes that, beginning at birth, the human brain contains a mechanism for both observing and executing what others do.

By imitating elders early and often, infants get drawn into social encounters that push them toward the realization that other people have thoughts, feelings, and desires, Meltzoff adds. "Imitation is the bud, and empathy and moral sentiments are the ripened fruit, born from years of interaction with other people already recognized to be 'like me,'" he says. Cultural traditions similarly thrive on youngsters at replicating what their elders do.

It's unclear, notes Mikael Heimann of the University of Bergen in Norway, how some newborn infants immediately re-create facial displays using their immature nervous and visual systems while don't exhibits this skill for a few days or even weeks.

Still, perception and action remain intertwined throughout life, contends Wolfgang Prinz of the Max Planck Institute of Psychological Research in Munich who studies adult imitation. Prinz finds, for example, that volunteers best reproduce a series of hand gestures demonstrated by an experimenter when they can again view the formerly moving hand, held still, in its final position, For the German researcher, this result highlights people's facility--no matter their age--at re-creating actions that have perceptible goals.

REFLECTIVE BRAINS Scientists now suspect that perception and action, imitation's indispensable ingredients, mix at certain neural hot spots. A 1996 study led by Giacomo Rizzolatti of the University of Parma in Italy identified neurons in the so-called premotor cortex of monkeys that discharge electrical impulses both when the animals perform an action, such as grasping or manipulating an object and when they watch an experimenter do the same.

"Mirror neurons seem to represent the goal of actions," says Parma's Christian Keysers, a colleague of Rizzolatti.

Recent findings bolster Keysers' argument. For instance, mirror neurons respond comparably when monkeys see an experimenter pick up an orange from a table and when they later watch the same person reach behind a screen placed on the same table. The same cells stay calm ff monkeys see a hand extend behind the screen without previously having observed an object on the table.

Moreover, many mirror neurons get fired up when animals simply hear sounds that. They've learned to associate with specific actions, Keysers says. This neural reaction occurs when monkeys. listen to the recorded sound of paper ripping after they've watched and heard a person ripping a paper. It doesn't occur ff they simply hear the sound. The cells similarly fire when the monkeys observe a person shelling peanuts and then hear peanut shells being broken apart.

Another investigation, led by UCLA's Iacoboni, has identified mirror neurons in people. These 'perception-and-action' cells reside within Broca's area, a brain structure involved in speech production and situated roughly where the monkey premotor cortex lies. The corresponding locations of human and monkey mirror neurons bolster Iacoboni's suspicion that brain tissue with ancient credentials as a crossroads for performing and observing hand and mouth actions evolved into a human speech center.

Mirror neurons reside within a three-step brain network that coordinates imitation, he theorizes. An initial visual description of an action sequence gets worked out in the superior temporal sulcus, reported David I. Perrett of the University of St. Andrews in Scotland, at the recent Cognitive Neuroscience Society meeting. The posterior parietal cortex then sorts out bodily movements corresponding to the observed actions. Finally, the premotor cortex identifies an action goal.

Empathy depends on collaboration between this imitation network and areas that regulate emotion, according to results of Iacoboni's latest research. People stoke their empathic skills by unconsciously mimicking the postures, mannerisms, and facial expressions of others (SN: 10/80/99, p. 280). Subtle impersonations of this ,kind invoke emotional states in the brain that simulate how the other person feels, Iacoboni and his coworkers assert in an upcoming Proceedings of the National Academy of Sciences.

The scientists used a functional magnetic resonance imaging (fMRI) scanner to measure blood-flow changes in the brains of 11 adults as they observed images of six facial expressions of emotion and then imitated each expression while trying W generate a corresponding internal feeling. Expressions depicted happiness, sadness, anger, surprise, disgust, and fear.

Both observation and imitation of facial expressions yielded blood-flow increases--an indirect sign of intensified neural activity--in a set of brain areas that includes the imitation network and some regions involved in emotion. Overall activity during imitation generally outweighed that during observation.

Furthermore, imitation stimulated blood flow in the insula, an area sandwiched by imitation structures on top and emotional centers below. The insula relays messages between imitation and emotion regions, Iacoboni suggests.

Brain-imaging studies are now under way to examine activity in the imitation network and in related structures that contribute to empathy at different ages, from infancy through adolescence, the UCLA researcher adds.

Studies of infant monkeys are also needed, Meltzoff says, to determine whether mirror neurons are present and functioning at birth.

EMPATHIC ANIMALS Neural discoveries about imitation and empathy underscore the capacity of many creatures to pick up on the emotional states of their compatriots, argue Stephanie D. Preston of the University of Iowa Hospital and Clinics in Iowa City and Frans B.M. de Waal of Emory University in Atlanta. Animals that live in groups develop varying degrees of empathy, with the most extensive empathy emerging in primates, Preston and de Waal propose.

They've developed an explanation that accounts for a wide range of suggestive evidence for empathic reactions in animals, including rats, monkeys, and chimpanzees, the researchers say. Regardless of species, the perception of another's emotional responses in a particular situation automatically activates what the observer knows about such feelings in similar contexts, according to Preston and de Waal. The observer then experiences bodily reactions consistent with the reproduced emotions and, if need be, acts on them.

The data aren't entirely consistent, though. For instance, monkeys have shown virtually no aptitude for learning to copy people's behaviors in the laboratory, although they possess mirror neurons that would be expected to groom them as imitators. A new study, directed by Francys Subiaul of Columbia University, suggests that adult macaques can indeed learn to repeat sets of simple actions as quickly and as accurately as 2-to-3-year-old children do.

A pair of monkeys and 12 toddlers saw a set of four photographs displayed from left to right on a computer each photograph in a randomly

Over a series of such displays, monkeys and toddlers learned to touch images in the demonstrated order with comparable success.

While monkeys may harbor unrecognized mental aptitudes, human infants cultivate imitation and empathy with unequaled vigor, comments Philippe Rochat of Emory University. From infancy to age 5, he points out, Youngsters go from simply aping facial movements to talking about other people's emotional states relative to their own.

Infants develop a sense of themselves as individuals distinct from others, thanks to a gift for noticing and then repeating their own behaviors, Rochat adds. Even before birth, babies repeatedly kick their legs, wave their arms, and bring their hands to the mouth. Such activities lead to an infant's realization that he or she exists apart from caregivers, in Rochat's view.

Self-imitation is probably at the origin of what is arguably one of the trademarks of human cognition-self-reflection" he says.

More than a century ago, U.S. psychologist James M. Baldwin made a similar argument. Baldwin held that infants at first don't distinguish between themselves and anyone else. Babies have never seen their own faces or encountered any other signs of their existence as separate entities. In this scenario, self-imitation and then the playing of imitation games with caretakers gradually drive home the distinctions between a child's own body and those of other people.

Baldwin's theory contrasts with Meltzoff's view that babies start out with a sense of self and imitate those whom they regard as "like me".

Whatever motivates munchkin mimicry, grown-up interactions thrive on the capability to step into someone else's shoes. For better or worse, empathy is as valuable to car salesmen and con artists as it is to teachers and psychotherapists. And for Jessica Lynch, it proved invaluable.