No one has worse manners than babies. They will not stop with the staring.
Fresh from the womb, we like to look at faces. An infant minutes old turns toward faces. We seem to sense that they’re important. But we also like to look at things that resemble faces—if something is facelike, that’s enough to attract a newborn’s attention. At birth, we are what scientists call “broadly tuned” to faces. We don’t discriminate finely; if something looks like it might be a face, we take it seriously. A Richard Nixon mask would be enough. (There’s no data on that, though.)
We’re so broadly tuned, in fact, that our antennae for faces isn’t human-specific: Newborns don’t prefer the faces of their own species over those of another primate. Without even having taken an introductory course in evolution, we see nonhuman primates as being a lot like us. And there’s more: At 6 months, babies are as good at telling apart monkeys as we are people.
Let’s pause to note how remarkable this is: I have been to the zoo. To me, all the monkeys there just look like monkeys. But infants seem to see their faces with the same richness and distinctness with which I see the faces of the other people in the café I’m sitting in.
Babies soon lose this skill: By 9 months, like adults, they’re no good at all at telling apart monkeys. That’s because as time passes, infants are able to see only what they already see in the world. This is a phenomenon called “perceptual narrowing” and it is best known for its effect on language acquisition: Very early on, infants stop being able to tell the difference between certain speech sounds that they’re not hearing. We have to hear these phonemes to know them. And we have to see the monkeys to know them, too. (This works the other way too: Monkeys exposed only to human faces prefer human faces.)
This affects how we see other humans, too. My wife, studying in Nanjing at a time when there were very few white people in Nanjing, had her fairly cosmopolitan Chinese roommate ask her, “How do you people tell each other apart? You all just look the same.” She wasn’t being rude; she was genuinely bewildered. Hilariously, when my wife returned to New York, she kept mistaking people on the street for people she knew. And then she thought, My roommate was right: All white people really do look the same. After a year of just seeing Chinese faces, she was, at least temporarily, no longer able to differentiate non-Chinese faces. Of course, this is famously the case with Americans who never leave America, too: Hence, all [insert ethnicity here] look the same. This isn’t racism. It’s just perceptual narrowing. And it happens fast: At birth newborns don’t prefer faces of their own ethnicity; at 3 months, they do.
Sadly, the science suggests that my youngest, who just turned 11 months, now has eyes only for humans. When I take him to the zoo, he sees other primates the same way I do: As other. It’s my fault. If I had the first year of his life back, I’d do my best to have more macaques around the house.