Experimenters mimics monkeys; monkeys dig it!
For several years, psychologists have been finding that we unconsciously imitate the people around us, and this imitation makes those people more comfortable with us. Apparently, we like to be with folks who move and talk as we do -- even though neither side knows that mimicry is occurring.
"Whenever two people interact, we would probably see mimicry happen if we look closely enough," says psychologist Annika Paukner. "We might find them taking the same body postures, sitting at lunch with the elbows on the table or leaning back and crossing arms."
Paukner works at the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Shriver, who died this week at age 88, was a pioneer in rights for people with intellectual disabilities and a founder of the Special Olympics.
In one study, Paukner said, an experimenter posing as a waitress got bigger tips when she echoed the customer's order verbatim instead of paraphrasing it. "Imitation increases the person's affiliation," Paukner says. "They say they like the other person more, have more empathy and more rapport, but they did not notice being imitated."
And now Paukner has found that capuchins, a South-American species of monkey, are also responsive to imitation -- and they likewise seem unaware that imitation is happening.
Aping the monkey
In one of a series of experiments, Paukner gave a ball to a capuchin, and had two people stand in front of the cage. Experimenter A, the control, performed typical capuchin behavior, such as poking, pounding or mouthing the ball. Experimenter B, the imitator, followed the monkey's behavior as exactly as possible. Although the behaviors came from the same basic repertoire, only B was doing a real-time imitation.
Careful examination of the monkey's gaze showed that it spent more time looking at the imitator, one indication of affiliation.
When Paukner's research group repeated the test and gave the monkey the choice to sit close to one experimenter, significantly more of them moved toward the imitative B. "We gave them a choice to sit in front of the imitator or the non-imitator, and the monkey chose to be near the imitator," says Paukner. "We interpret that as measure of affiliation; they like the imitator better. Monkeys like to spend time with their friends, just like we do. Monkeys spend time with imitators because they like them better."
In both cases, simply acting like a monkey was not enough; rather, it was the act of mimicking that did the trick. "Our experiment used the strictest definition of imitation -- the exact same behavior at the exact same time," says Paukner. "The control person did monkey behavior, but it did not match what the monkey was doing."
In a less-definitive experiment, B imitated while A stood still, but in that case, it was not clear whether the monkey was responding to the imitator's movement or to the imitation, Paukner says. "We are really isolating the effect of the imitation," she says.
How can imitation have so much power when, as studies have proven in the human case, neither side is aware of the imitation? Many experts speculate that imitation works as a "social glue." "The theory was that imitation helps bring a group together, helps forge group membership," says Paukner. "People who get on well together have an evolutionary advantage," and that might explain why we unconsciously imitate -- and unconsciously respond to -- imitation.
Psychologists have done plenty of studies on human imitation, which we also use for other purposes, such as learning to tie shoes or drive cars, or even to follow social conventions and avoid irritating our friends and neighbors.
But imitation has other purposes, Paukner says: "It's also used to regulate a group, to increase harmony, to have better social relationships. I think it's quite significant." The new study, she says, shows that this kind of imitation "goes beyond the individual and affects the whole group; it's the first time this has been shown in any non-human primate."
And yet the capuchins, like the humans who have been studied, seem oblivious about what is affecting their behavior, Paukner says. "They see that something is different, but I'm not sure they understand they are being imitated," she says.
If capuchins respond to imitation, it follows that they must also imitate -- but do they? "That's an interesting question," says Paukner. "If you talk about it on this strict level, as an exact copy of movements, they don't do that. But they are very easily influenced by others. If one monkey picks something up and drops it, another will become interested, and come over and touch it."
So do capuchins imitate, and how might that affect their relationships? "We will test that," says Paukner. "It's much harder to get two monkeys to synchronize, but we are working on that."
David J. Tenenbaum
• Capuchin Monkeys Display Affiliation Toward Humans Who Imitate Them, Annika Paukner et al, Science, 14 August 2009.