海角大神

Imitation is the sincerest form of flattery, or so the saying goes. But more than that, it might also be at the root of what makes us, well, human.

Starting in infancy, humans begin imitating others around them, sticking their tongues out when a caretaker does, holding toy telephones up to their ears, and waving back to anyone who waves at them. Imitation continues into adulthood, as we pick up the body language of someone we like, ask friends where they bought their 鈥渇abulous red shoes,鈥澛燼nd don a certain company鈥檚 apparel because Michael Jordan wears it.

Imitation can get a bad reputation, but researchers say our species鈥� drive to imitate so readily is a significant mechanism through which we learn social norms, integrate into society, and build social connection. And, they say, this level of imitation might be what sets聽us apart from other species and may have set us on the path to building an advanced society.

"Human beings are the premier imitators on the planet," says Andrew Meltzoff, co-director of the University of Washington Institute for Learning and Brain Sciences.

Other animals also imitate some actions, but they鈥檙e mostly relevant actions that help achieve a goal or are biologically important for survival. Humans are 鈥渋mitative generalists,鈥� Dr. Meltzoff says, and can imitate actions 鈥� actions on objects, postures, vocalizations, and even nonsensical behavior 鈥� before even speaking in full sentences.

But the question for researchers remains: Do any animals other than ourselves imitate beyond the basics necessary for survival?聽The answer could tell us what makes humans unique.

To sort that out, comparative psychologists are testing different animals to see if they, too, will 鈥渙verimitate,鈥� or imitate actions that don鈥檛 help them achieve a goal.

"It seems to be a really critical part of our cultural capacity that we're willing to copy stuff even though we don't really know why we're doing it," says Zanna Clay, a primatologist and comparative psychologist at the Durham University in Britain. So she decided to put our most social ape cousins, bonobos, to the test.

In a comparative experiment, Professor Clay demonstrated to a bonobo or a human child how to open a little wooden box with a reward inside. Before opening the box, she performed some extraneous actions, like rubbing the back of her hand on the box or tracing her finger over it gently. Then, without giving any instruction, she gave the subject a matching box.

Nearly 80 percent of the children Clay tested imitated the non-rational actions before trying to open the box, according to published Monday in the journal Child Development. But the bonobos skipped the nonsensical actions and went straight for opening the box, suggesting that bonobos don鈥檛 overimitate.

Some animals do copy things that might seem strange. For example, parrots, classic vocal imitators, often learn to make the sound of a microwave beep, says Irene Pepperberg, a researcher聽at Harvard University known for her work on parrot cognition. The birds notice that when the microwave beeps, she says, their owners run to it. 鈥淎nd so the bird says, well, maybe if I make that noise, you鈥檒l come to me, and then I can be with you and be part of the flock.鈥�

Still, the reason parrots want to be in their owner's 鈥渇lock鈥澛爃as to do with survival,聽Dr. Pepperberg explains. 鈥淚n the wild, a single parrot is a dead parrot. It can鈥檛 forage and look for predators at the same time. The idea is that you need to learn the lingo of your flock to be accepted into that flock,鈥� so pet parrots learn to make human-related sounds as a bid to fit in.

Flocking together

Humans use imitation to fit in with their 鈥渇lock,鈥� too 鈥� even as infants.

When a baby sticks its tongue out in imitation of a tongue-protruding adult, it might seem like a silly little thing, but it鈥檚 actually a little baby鈥檚 way of saying, 鈥渉ey! you're like me.鈥�

Meltzoff describes this as the 鈥渓ike me鈥� mechanism of learning.

Babies鈥� brains are wired to learn from others before they can even speak to ask questions, Meltzoff says.

Before becoming fully developed humans,聽babies have to figure out what a human is, and that鈥檚 where the 鈥渓ike me鈥澛爉echanism comes in. When babies look around, they might see trees moving, or the mobile over their crib moving. But it鈥檚 not the plant or inanimate object that they imitate. Even as an infant, humans can recognize their caretakers as an entity like them.

Imitation is 鈥渁 chief channel for learning to be a human,鈥� Meltzoff says. 鈥淸Children] become little members of their culture by imitating those around them.鈥�

Some researchers think this sort of affiliative, indiscriminate imitation might be part of the evolutionary advantages that lay the groundwork for humans to build an advanced society unique in the animal kingdom.

Social modeling 鈥渋s probably one of the most functional systems of learning,鈥� says Albert Bandura, a professor emeritus at Stanford University famous for his work on social learning. "It shortcuts all the laborious trial and error" of learning by direct experience, the other basic mode of learning. "I can't imagine a culture in which our language and our complicated skills and social systems were all developed by trial and error learning."

Engineering feats like the airplane wouldn鈥檛 have been achievable if humans couldn鈥檛 faithfully copy each other鈥檚 inventions and build on them, Clay agrees.

Imitation lubricates social connection

In a social setting, imitation sometimes is mixed up with with mockery. But if someone copies your style or picks up your mannerisms, they might actually be making a bid for social connection with you.

Some social connection built on imitation is affiliative, similar to the 鈥渓ike me鈥� mechanism, using imitation to follow social norms. Like a parrot will repeat its owner鈥檚 phrases to fit in with the human flock, we watch to see if a colleague shakes the boss鈥檚 hand before following suit, or laugh at a joke in a new social group as a way of saying, 鈥渟ee, we have the same humor, let鈥檚 be friends.鈥�

Imitation in social bonding can also be less intentional, as some psychologists have noted that when two people on a date mutually like each other, they subconsciously mirror each other's body language, for example.

People respond to being imitated, too, Meltzoff says. When a little baby coos back to its cooing mother, the mother is thrilled to be imitated, which has been confirmed with brain scans. And that鈥檚 bonding. It's almost like 鈥渢he mother and baby are on their first date and it's the most important date they'll ever have.鈥�

Imitation might also be linked to empathy, as mirroring another person鈥檚 actions can at least partially help you experience their perspective, Meltzoff suggests.

There鈥檚 still a lot of research left to be done to determine just how entrenched and unique imitation is in humanity. But, Clay says, our sensitivity to cues from others and tendency to overimitate suggests that if we can figure that out, we may be able to understand what makes humans, human.