I remember a lamp that stood on the floor in the opened doorway to the bedroom where my sister Liv and I slept. My mother put it there every night so the darkness would never be total. This is an old memory and around it are the usual fogs that dim recollection, but the light offered the hope that blackness would not snuff out the visible world entirely during my anxious transition to sleep.

Bedtime rituals for children ease the way to the elsewhere of slumber — teeth brushing and pajamas, the voice of a parent reading, the feel and smell of the old blanket or toy, the nightlight glowing in a corner. For the child bedtime means double separation, not

only from wakefulness but also from Mother and Father. I wonder how many glasses of water have been fetched, how many extra stories have been read and lullabies sung, how many small backs and arms and heads have been rubbed in the past week in New York City alone.

In the “Metapsychological Supplement to the Theory of Dreams,” Sigmund Freud wrote,

We are not in the habit of devoting much thought to the fact that every night human beings lay aside the wrappings in which they have enveloped their skin as well as anything which they may use as a supplement to their bodily organs…for instance their spectacles, their false hair and teeth and so on. We may add that they carry on an entirely analogous undressing of their minds and lay aside most of their psychical acquisitions. Thus on both counts they approach remarkably close to the situation in which they began life.

Children are even closer to that beginning than we adults are. Night looms larger because time moves more slowly — a child’s day represents a much larger percentage of life lived than it does for any parent. The mental capacities of young children do not include the rationalizations grownups use to explain to themselves that a fear is unjustified. The three-year-old does not yet live in a world of Newtonian physics. Not long ago, I saw a film of a psychology experiment, in which young children worked hard to get their oversized bodies into toy cars.

Sleep resistance, bouts of insomnia, nightmares, night terrors, crawling into bed with parents in the middle of the night – all these are so common among children it seems fair to call them “normal.” Infants, of course, are notorious for refusing to sleep and wake on command. The exasperated parent can now call a counselor who, for a fee, will come to your house and address your baby’s “sleep issues.” As far as I can tell, these interventions are directed more at exhausted parents than at the welfare of children. They consist of behaviorist techniques that “teach” the offspring to give up hope for comfort at times inconvenient for her progenitors. The message here is an early-life version of self-help.

But sleep training is counterintuitive. When your baby cries, you want to go pick her up and rock her back to sleep. If anything has become clear to me it is how quickly advice about raising children changes. In the early twentieth century when the dictates of behaviorism reigned supreme, experts on childcare advocated strict feeding and sleeping regimens and discouraged parents from playing with their children. I am always suspicious of those who impose “rules” on child rearing. Every child is different in terms of temperament and learning, and every parent responds to a particular child, not some generalized infant or youngster. And much of that response is not intellectual but deeply felt.

The truth is that a baby develops emotionally and cognitively through the reflective exchanges he has with his mother (or what is now called the “primary care-giver”). The essential brain development that regulates emotion takes place after birth, and it happens through the back-and-forth of maternal-infant attunement — looking, touching, comforting. But there is also an intrinsic alarm system in the brain that the neuroscientist Jaak Panksepp calls the PANIC system. All mammals exhibit what scientists call “distress vocalizations” when they are separated from their caretakers. They cry when they’re left alone. As Panksepp writes, “When these circuits are aroused [PANIC system] animals seek reunion with individuals who help create the feeling of a ‘secure neurochemical base’ in the brain.”

I couldn’t bear to let my baby cry in the night, so I didn’t. For years I read to my daughter while she drifted off to sleep, her fingers in my hair. As she grew older, I continued to read to her and, after I had said goodnight, she would lean over and switch on a tape of Stockard Channing reading one of the Ramona books by Beverley Cleary. The tape had become a transitional object — a bridge between me and sleep. D.W. Winnicott, the English pediatrician and psychoanalyst coined this term for the things children cling to — bits of blanket or stuffed animals or their own fingers or thumb — that occupy a space between the subjective inner world and the outside world. These objects are especially necessary at bedtime when, as Winnicott writes, “From waking to sleeping, the child jumps from a perceived world to a self-created world. In between there is need for all kinds of transitional phenomena — neutral territory.” I vividly remember my sister Asti’s ragged blanket — she called it her “nemene.” One of my nieces used three pacifiers — one to suck and two to twirl. How she loved her “fires.”

There is no reason we should expect young children to enter the nocturnal darkness of sleep and dreams without help. Parental rituals and transitional objects serve as vehicles for making the passage and, indeed, to a child’s ability eventually to comfort himself. Freud was surely right about the strangeness of preparing for bed and about the fact that the human mind is undressed in sleep. The so-called executive part of the brain — the bilateral prefrontal cortex — is largely quiet, which probably accounts for the disinhibition and high emotion of many dreams. It is not always easy to go to that region that lies beneath wakefulness, to relinquish the day and its vivid sensory reality. And for a small child the most vital part of that reality is Mother and Father, the beloveds she must leave behind as she drops into the very private land of sleep.

Siri Hustvedt is the author of four novels, including “The Sorrows of an American” and “What I Loved,” and two books of essays. Her most recent book, “The Shaking Woman or A History of My Nerves,” is a neurological memoir. Her work has been translated into 29 languages. Her Web site is sirihustvedt.net.