Larkin passed an interesting milestone. For the first time, she was afraid of something. Not something physical, like a dog or loud noise, but something imaginary.

We have a pull-down staircase to our attic, and early on she became fascinated by the yellow cord hanging down from it. One time I pulled the cord, and the door began to open downward, its springs creaking weirdly. Larkin stared, transfixed, up into the void. "Dowken!" she said — her word for "darkness."

Later on, I began asking her, "Who lives up there?", then answering myself: "It's a mystery." She picked up the word, cheerfully mispronouncing it. "It's a mistletree, Dada!" she'd say. And so it went, until one day last week, when for no apparent reason the word — and the attic — took on a new dimension. I pulled on the cord, but this time as the stairs creaked down and darkness loomed overhead, Larkin's face showed a frown of worry.

"She's afraid," Molly said afterward. "We're going to have to stop making it scary."

Are we? I'm learning there's a divide between parents who approve of some spooky chills and those who don't. There's no doubt which camp Molly belongs to. She herself hates scares. One often-told story in our marriage concerns the night I dragged her to see The Blair Witch Project — then later hung a little talismanic effigy of sticks, like the ones in the movie, from the porch ceiling, and tricked her into going outside. I thought it was hilarious. She thought it was sadistic.

With Larkin, Molly has zero tolerance for anything like that. Larkin has a big book of teddy bear photos, and in one photo the bears are wearing masks. "Oooo," I'll say, "scary bears!" And Molly quickly corrects me, "No, not scary, just dressed up!" She doesn't even want Larkin to form the concept of scary.

Of course, everyone knows that life itself contains scary stuff, and that time will bring its share of the dreadful. But what lesson should parents of a toddler draw from this? Don't invoke fake scares, since she's going to get enough of the real thing anyway? Or the opposite — get her used to scariness by practicing it?

When I was little, my room had a door leading to a cavernous storage room, and on a winter night the wind would whistle through the crack beneath it. I'd lie in my bed, conjuring horrific beasts. I can recall the dread those fears provoked, and the shame, too. But I'm also aware that scariness tantalized my imagination. My father used to tell me a bedtime story about a haunted house and a group of friends who investigated it on a dark night. One by one they went in, only to meet gruesome ends, each on a different floor of the house. I shuddered — and begged him to tell it again and again.

So I'm of two minds about scariness. Meanwhile, Larkin is growing ever more alert to the concept. Just today, while carrying her down the back steps, Molly slipped and almost fell. That was scary, she said afterward.

"Scary?" Larkin asked. "Mama scary?"

Along with scariness comes badness. Recently we rented The Red Balloon, and Larkin was riveted by the scene in which the tough boys chase Pascal through the streets of Paris, trying to steal his balloon. She keyed right into their wicked intentions. "Bad boys," she said. "They take Pascal balloon away!" A few days later, Fabiola, who cares for Larkin in the mornings, reported that out of the blue, Larkin had begun talking about "los hombres malos," or simply "los malos."

And now the Monsters have appeared. This followed an episode of Curious George in which the cuddly little simian becomes terrified of the dark, and innocent objects in his room are transformed every night into monsters. Since then, Larkin's radar has been picking up strange presences. "The monsters are there," she'll say.

What monsters? Where?

"Over there," she says, pointing.

I doubt it's coincidental that a toddler's discovery of fear goes hand in hand with a new selfishness. In the last few weeks, the first-person possessive adjective has saturated Larkin's chatter. Everything is mine, mine, mine: my books, my blanket, my binky. This can get absurd. Her Lego tower falls over, and she cries out, forlornly, "My tower! My Legos!" I close the door to the bathroom, and she wails, "My bathroom!"

I suspect that such selfishness is literal — more about her self than her possessions. And that this new awareness of herself in the world brings with it the converse, the world beyond the self; discovering the "me" also means pondering the "not-me." Imagine what it must be like to realize you exist, when up till now you've just been…well, existing. It must spark fascination — and fear.

Upstairs in Molly's and my bedroom, a trap door in the floor leads to a back staircase that we blocked off during a renovation shortly before Larkin was born. The staircase once belonged to an in-law apartment, and now it serves as our emergency exit in case of fire, but basically it's a sealed-off crypt, a staircase to nowhere. Recently, while playing with toys on the floor in our room, Larkin discovered the trap door. She fingered the brass handle. "What's this?" she asked. I told her about the staircase and the former apartment.

"Is mystery down there, Dada?" she asked.

I wondered, what exactly does "mystery" mean to her? Is it anything dark? Anything behind a closed door? Anything we won't let her explore? "Yes," I said, "It is."

"I want to go down there!" she said, pulling at the handle. "I want to go to mystery, Dada!"

For a moment I had half a mind to unlock it, pull up the hinged trap door, and let her stare into the crypt. Maybe make a suitable ghostly moan as the dark depths opened up below. But then I rethought.

"Not today," I told her. "We'll do that some other day, OK, sweetie?"

She pondered it for a long moment. "OK!" she said, finally, and went back to her toys and the sunlit room.