This guest post is by Bruce Bower, who has covered behavioral sciences for Science News for 32 years.
For a landmark 1977 paper, psychologist Andrew Meltzoff stuck his tongue out at 2- to 3-week-old babies. Someone had to do it. After watching Meltzoff razz them for 15 seconds, babies often stuck out their own tongues within the next 2½ minutes.
Newborns also tended to respond in kind when the young researcher opened his mouth wide, pushed out his lips like a duck and opened and closed the fingers of one hand.
Meltzoff, now at the University of Washington in Seattle, and a colleague were the first to report that babies copy adults’ simple physical deeds within weeks of birth. Until then, most scientists assumed that imitation began at around 9 months of age.
Newborns don’t care that imitation is the sincerest form of flattery. For them, it may be a key to interacting with (and figuring out) those large, smiley people who come to be known as mommy and daddy. And that’s job number one for tykes hoping to learn how to talk and hang out with a circle of friends. Meltzoff suspected that babies enter the world able to compare their own movements — even those they can feel but not see, such as a projecting tongue — to corresponding adult actions.
Meltzoff’s report has inspired dozens of papers on infant imitation. Some have supported his results, some haven’t. A new report, published May 5 in Current Biology, falls in the latter group. The study of 106 Australian babies tracked from 1 to 9 weeks of age concludes that infants don’t imitate anyone.
Nearly 40 years after his classic paper appeared, Meltzoff is sticking his tongue out again —metaphorically. He argues that the new investigation didn’t give babies a fair chance to strut their copycat skills.
In the study, psychologists recorded the frequency of nine actions — tongue stick-outs, mouth openings, smiles, frowns, pointing with an index finger, grasping and making “mmmm” or “eeee” sounds or tongue clicks — shortly after babies observed a female experimenter perform each action. Infants were also shown a spoon protruding through a tube (simulating a projecting tongue) and a box opening up (like a mouth going from closed to open).
At no age did infants consistently copy any action, the researchers say. Babies stuck out their tongues just as often whether they saw an adult smiling or sticking her tongue out, for example.
Other studies have found that babies stick their tongues out when aroused by flashing lights or lively music, notes psychologist Cecilia Heyes of the University of Oxford, who didn’t participate in the new investigation. Newborns’ tongues pop out after seeing an adult do the same thing at close range because the kids are amped up, she contends.
Give the little copycats a break, Meltzoff responds. In the new study, babies saw a total of 11 actions appearing one right after another, with 15 seconds to 1 minute to respond to each demonstration. Newborns need more time than that to coordinate a movement like one they’ve just observed, he asserts. Another problem: the researchers discarded cases of imitation if babies had looked away from a demonstration for more than two seconds. Babies, like adults, often look away when absorbing information or organizing a response, Meltzoff says.
Still, babies repeated the experimenter’s tongue protrusions more than any other action in the new study, he adds.
Obviously, much remains to be learned about how babies think. What’s clear is that psychology and other scientific disciplines must get beyond the current obsession with trying to find the same statistical trend — such as newborns poking out their tongues especially frequently after seeing someone do the same — in different laboratories under conditions that always vary to some extent.
Science needs organizing principles, or theories, that make testable predictions. Meltzoff, for instance, suspects that infants begin sensing how parts of their own bodies move while still in the womb. That helps newborns recognize other people to be “like me” and match their actions to self-produced actions, he theorizes. If studies Meltzoff is now conducting determine that certain parts of infants’ brains are already dedicated to perceiving and moving particular body parts, such as the tongue, that would support the “like me” theory.
Perhaps a future study will pit different theories of how and when infants become copycats against each other. Babies everywhere would appreciatively stick out their tongues.