Parenthood in early infancy is equal parts tedium and astonishment. The trick is telling the two apart.

This is harder than you might think. Pointing, for example, is not an obviously astonishing act. I have already pointed several times today and no one was astonished. But when a baby points ecstatically at a puppy, or responds to someone else pointing at that puppy, we should marvel at him: We have just witnessed an astonishingly complex act. In fact, by pointing, that baby is, in a very real way, acting out what makes us uniquely human.

Over the last decade, a series of studies out of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have made a very good argument for marveling at your pointing infant. A group of psychologists there have documented that infants, beginning at around 1 year of age, point and react to other people pointing in remarkably sophisticated ways. Babies point to refer to events in the past and the future. They point to refer to things that are no longer there. They can figure out, when an adult points across the room toward a group of objects, what exactly the adult is gesturing toward (the toy they’ve previously played with, say). They can deduce that, by pointing, an adult is trying to communicate something specific (find that toy hidden in that bucket). And not least of all, babies point because they want to share their experience of the world—that puppy—with someone else.

These may just be the talents out of which humans managed to assemble minor things like culture and language. “The basis of language is all right there in gestures,” says Malinda Carpenter, a developmental psychologist at Max Planck, who conducts research on larger issues of cultural cognition. When Carpenter sees an infant pointing out a clown to his mother, she sees a meeting of the minds: That baby is coming together with someone else to share his experience of—and his attitude toward—something else.

This is declarative pointing—showing something to someone else. (It’s very different from imperative pointing, which is pointing to request something. Imperative pointing is what Donald Trump does.) Of course, you could interpret this kind of pointing in a less sophisticated way than a meeting of the minds. Maybe the infant just wanted more attention. Maybe he just wanted the experimenter to see the toy, not to share in having seen it. Maybe he was just pointing for his own sake; maybe it had nothing to do with anyone else.

So Carpenter and her colleagues designed an experiment: They put infants in a highchair across from a screen with lots of closed windows; when a window opened, a puppet popped out. The infants did what any sensible person would do when face-to-face with a gyrating puppet: They pointed. To test different interpretations of what that pointing meant, the experimenter varied his reaction. The only reaction that the babies found satisfying—the only reaction that inspired them to keep pointing for each puppet—was when the experimenter looked back and forth between them and the puppet, saying things like, It’s Grover! That’s so interesting! The infants were delighted by this response. They wanted the adult to share the totally awesome experience of this totally awesome puppet. When the experimenter failed to do this, Carpenter says, “The kids stopped pointing for this weird adult, who wasn’t giving them what they wanted.” When the adult only looked at the infant, the infant often pointed again at the puppet, as if to say, No, you dunderhead—over there.

The infants didn’t just want attention to themselves. They wanted someone to share in their experience of the world. “It’s just so rewarding to have somebody else share your opinions about something,” Carpenter says. “Especially for a 12-month-old baby, but also for us. Imagine if you had a friend who never found the same things interesting that you did. It’s really rewarding for us, too.”

If you look closely enough at those outstretched fingers, you can see the roots of human cooperation. Our primate relatives don’t point declaratively. They point imperatively, like Donald Trump, and they will point to inform an experimenter where an object is—but only when there’s something in it for them, like food. But an ape wouldn’t point to a puppet, or anything else, for that matter, just because it was really cool. It’s a question of motivation, Carpenter says. “It’s just not important for them to share their opinions of things with others.”

Pointing to share an opinion builds on the foundation of what psychologists call joint attention—when two people pay attention to the same thing (and are aware that they’re both paying attention to that thing). Joint attention arises out of what Michael Tomasello, who heads the Developmental and Comparative Psychology Department at Max Planck, has called the nine-month revolution. Out of it grows the basis of pretty much all human achievement: the motivation and the ability to work together toward shared goals. (Apes never get there: They have the attention part but not the jointness.)

All this is enough for the appearance of pointing in infancy to be the most interesting mundane gesture ever. But as Carpenter and her colleagues have demonstrated, declarative pointing is not the only sort that babies do. “Infants from 12 months on, and even earlier in some cases, are pointing to express all kinds of complex meanings,” Carpenter says. For example, they will point just to inform you of something. “So if you’ve dropped something and don’t realize it, infants will point it out to you. There’s nothing in it for them. It’s just to help you.” In addition, babies will not just point to refer to an object that is no longer there—what psychologists call an absent referent—they take into account whether the adult has previously seen the object or not. In some cases, they seem to be trying to tell the adult what was there.

They can also deduce meanings based on who is pointing. When an adult and a baby are tossing toys in a basket together and the adult points to a toy and says, “There!” the baby will toss that toy in the basket too. He understands the pointing to refer not just to the toy but to the game they’re playing together. However, when another adult who isn’t playing the game points to an object out of the blue and says, “There!” the baby won’t toss it in the basket. (Who knows what that crazy adult means?) They also deduce meanings based on how purposeful the pointing appears: If an adult points to an object while looking distractedly at her wrist, the infant seems to assume that this pointing is happenstance, not an attempt to communicate with him.

Pointing, in other words, seems to call on a sophisticated understanding of what is going on in the heads of other people. “That suggests that they can do so much more with pointing prelinguistically than we ever thought before,” Carpenter says. Until recently, people thought that this sort of knowledge only emerged with language. Carpenter herself went to graduate school because she was interested in language. But then she started looking at prelinguistic gestures. “And everything’s already there! I completely lost interest in language because you can see so much complexity already in infants’ gestures.”

My youngest child is now 10 months old. We have exchanged deeply meaningful glances about fish pull-toys. He holds fabric vegetables up for shared approval.

We don’t know why pointing happens when it does. But in all likelihood, sometime soon—after months of my pointing toward interesting things and him drooling and staring dumbly at my finger—it will click. His head will turn.

And then, perhaps when he sees a totally awesome puppet, he will stretch out his own finger. This is a thrilling moment. Instead of listening to yet more of my opinions—and keep in mind that I’ve been monopolizing the conversation for a year now—he can offer his own. As Carpenter says, “The infant herself is able to say, ‘This is what I’m interested in.’ ” And she knows that you’ll be interested in what she has to say.

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Nicholas Day’s book on the science and history of infancy, Baby Meets World, will be published in April. His website is nicholasday.net.