I opened my feature on mirror neurons for Scientific American Mind by telling how my son Nicholas imitated me sticking out my tongue in his first hour. I regret I can offer you no film of that.
Thanks to PLOS Biology, however, I can now offer you videos of a baby macaque monkey essentially doing the same — that is, imitating lip-smacking and sticking-out-of-the-tongue — in these video clips from “Neonatal Imitation in Rhesus Macaques” in PLOS Biology.

Monkey see, monkey do.
On the left, imitation of mouth-opening; on the right, of “tongue protrusion”
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The photos above (not much, I admit) pale next to the videos of this little macaque watching and imitating the nattily garbed researcher. There’s also a video clip of a baby macaque in a more naturalistic setting, apparently imitating some mouth movements its mother makes during a break in nursing. (Nursing mothers, or mothers who have nursed, will flinch, as did my wife, when the monkey rather roughly releases the nipple to look up at the mother.)
The paper itself is a nice study of how imitation — the kind presumably driven and enabled by mirror neurons — takes particularly literal and robust form in the first hours and days of life. This quick, attentive imitation had largely disappeared by the time the monkeys were a week old; they paid close attention but didn’t necessarily imitate. Chimps and people tend to imitate these actions longer — possibly, the authors say, because “motor and cognitive development in macaques is much more rapid than in humans and chimpanzees.” They will leave their mothers to explore starting at a week, and they seem less interested in gazing at goofy faces at 2 weeks than people or chimps do.
I found it a particularly interesting paper — with a high fun factor, which never hurts. When you’ve absorbed the considerable neurosci interest you can take pleasure in the cute monkeys (though not as cute as our Nicholas!*) — and there’s an extra geeky pleasure in seeing how glamorous life in a neuro lab is.
*Bonus photo: My son Nicholas, 4 weeks old, imitating his dad’s smile:
