Extinction: Why Cry It Out is Extinct

I have argued before that no modern sleep expert recommends pure “cry-it-out” (CIO) sleep training. Here I want to explain in more depth where CIO stands currently. In order to simplify the discussion, I’ll call it by its more technical name, extinction. Some versions of this method are widely recommended today. One kind, unmodified extinction, has all but disappeared, or become extinct. That’s a shame, because it is highly effective, as I’ll explain below.

When it comes to any kind of human or animal behavior, “extinction” refers to the disappearance of a behavior in the presence of a stimulus. Pavlov famously could make his dogs salivate when he rang a bell (the stimulus). The dogs had learned that the bell meant Dr. Pavlov was about to feed them. That was only the first part of the experiment. In the second part, the dogs stopped salivating after a while. In other words, the salivating behavior “extinguished” with time.

Extinction in Sleep Training

When it comes to sleep training, the behavior we are trying to extinguish is crying. In sleep training, there are now three versions: Extinction with parental presence, graduated extinction, and unmodified extinction.

Extinction with parental presence is a version of CIO where the parent stays in the baby’s room, but does not respond to cries. With time, the caregiver moves farther away from the crib. Finally, the baby sleeps alone. This method has been championed by Kim West. She renamed the method “The Sleep Lady Shuffle”.  The terms get even more confusing because West’s followers refer to her method as “bedtime fading”. This is very different from true fading techniques.

The graduated variety is today better known as “Ferberization“. The method involves answering the baby’s cries, but doing so at longer intervals every night until the baby goes to sleep on her own.

Finally, we come to the true dinosaur, the unmodified CIO technique, sometimes called “cold turkey”. The villain of the CIO story is a late-19th century pediatrician named Luther Emmett Holt. The first time we see the words “cry it out”, they appear in Holt’s 1894 catechism “The Care and Feeding of Children.”


Holt’s book is not a “sleep book”. In fact, there is no section on bedtime routines such as the kind we’ve grown used to. There is, however, a section on the types of infant cries and what to do about them. The section that follows is really about “problem crying”.

What should be done if a baby cries at night?

One should get up and see that the child is comfortable—the clothing smooth under the body, the hands and feet warm, and the napkin [diaper] not wet or soiled. If all these matters are properly adjusted and the child simply crying to be taken up, it should not be further interfered with. If the night cry is habitual some other cause should be sought.

How is an infant to be managed that cries from temper, habit, or to be indulged?

It should simply be allowed to “cry it out.” This often requires an hour, and in extreme cases, two or three hours. A second struggle will seldom last more than ten or fifteen minutes, and a third will rarely be necessary. Such discipline is not to be carried out unless one is sure as to the cause of the habitual crying.

Holt is describing a particular kind of crying here. This is crying born of habit. These are babies who have learned that crying can draw her parents’ attention. I suspect he is referring to babies who’ve acquired “object permanence“. That is, the baby knows that mom or dad is still there when they leave the room, and she can induce them to come back.

Dr. Holt is not describing a way to get a baby to fall asleep. He is describing a solution to a problem. That sleep problem is “bad sleep associations“. For example, the baby won’t sleep unless she has physical contact with a parent, or if she has a binky in her mouth. Likewise, sleep books that discuss “cold turkey” or any other CIO technique are aimed at families that already have developed bad sleep associations and want to reverse them.extinction 3

The Moa is Extinct. So is the Cold Turkey

Of the three types of extinction methods, only unmodified extinction, or cold turkey, has disappeared. It has ceased to be (see video below). And yet, cold turkey has been tested experimentally and found to be extremely effective. Several arguments agains cold turkey have been raised, not least that the method stresses the baby and caregivers. These objections have also been tested and so far have proven to be false. Even the most-cited article arguing for the negative effects of CIO  failed to show that the stress hormone cortisol goes up in crying babies!

The main reason cold turkey has gone extinct is that it is really difficult to listen to a child cry. Most parents can’t handle it. I know I couldn’t (the boys’ mother was the stronger partner). Listening to crying becomes even more difficult because of a thing called the “extinction burst”. This is an increase in crying as the sleep training process proceeds. Sometimes the burst happens after it appears that you’ve succeeded and the baby is sleeping through the night. In either case, the stress for parents becomes too much.

A second reason, perhaps more important, is that many parents believe cold turkey CIO will psychologically damage the baby. There is absolutely no evidence for this. To the contrary, the evidence suggests that babies sleep trained with unmodified extinction get good quality sleep. Parents report better sleep for themselves and their children. Overall there are only positive results for the family.

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The reasons for the disappearance of a perfectly good sleep training method appear to be cultural, rather than scientific.

One more cultural factor deserves mention: consistency. Probably the number one reason why any of the extinction methods fails is that parents cannot or will not stick to the plan consistently. Consistency is the number one most important feature of any sleep training method, whether you are doing scheduled awakenings, bedtime fading, or the “Sleep Lady Shuffle” (which is, to repeat, extinction with parental presence).

To Extinguish This Line of Argument

  • The bottom line is that extinction methods are effective.
  • Extinction methods do not harm your baby or your bonding with her
  • Consistency, consistency, consistency. This is the essential piece of solving any sleep problem

Finally, let us explore the true meaning of life extinction with the help of our panel of experts, John Cleese and Michael Palin.

Sleep Schedules: Who Makes Them?

New parents who buy baby books and browse the internet may come to believe, reasonably, that there are two basic “philosophies” of sleep schedules for babies: parent-led and baby-led. It’s true that there are different philosophies out there (including combination philosophies), but no philosophy ever made a baby schedule.

“Schedule” is a funny word. In English the word schedule implies a scheduler, someone who makes the schedule. I explain to my clients that sleep schedules are a lot less scheduled than parents care to admit.

The philosophy I share with my clients is based on my belief that sleep schedules are a type of spontaneous order: The baby sleeps and eats at (roughly) the same time every day. It looks like a schedule! In fact, it is a schedule. But there was no scheduler.


I’ll get to my account of where I believe the two philosophies came from. But first, a word about the tendency to divide the world into groups.

Lumpers and Splitters

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Thiago Splitter

There world is divided into two parts: People who divide the world into two parts and people who don’t. That’s a joke, of course. But like many jokes, it reveals a truth about human nature. Some people are “splitters” and some are “lumpers”.

Splitters tend to see the world as divided up into categories. The task of the splitter is to find the appropriate category for everything. A splitter asks “how is this thing different from that thing?”

The world is divided into two parts: People who divide the world into two parts, and people who don’t.

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He is a lumper. Look it up

Lumpers tend to see the world as a series of connections among things. The task of the lumper is to find ways to lump everything into as few categories as possible. A lumper asks “how is this thing like that thing?”


I am a lumper by nature. I don’t know how or why I got this way. For me, lumping is the most intellectually-satisfying way to make sense of the world.  It informs the way I look at sleep schedules. Having said that, I don’t “lump together” the various sleep schedule philosophies into one group. Rather, I believe that the various philosophies arrive at the same end-point: the child (and parents) settle into a pattern that appears to be a schedule. Babies contribute to the development of a schedule, and parents play a role as well, but there is an important third party that plays a crucial role as well. I’ll get to that at the end of this post.

Baby Sleep Schedules: Parent-led vs. Baby-led

Prior to the 19th century, nobody thought much about baby sleep schedules, either parent-led, or baby-led. The concepts simply didn’t exist. All a mother had to guide her was the advice and counsel of experienced mothers in her community, first and foremost her own mother. Therefore, if one could say that there were such a thing as child-rearing philosophies, these were traditional philosophies. That is to say they were based on tradition: familial and cultural.

In mid-19th century, coincident with the creation of pediatrics as a medical specialty, there emerged what could be called the “era of scientific parenting”. Pediatrics came into being to solve two problems: infant mortality and malnutrition. By the middle of the 20th century, both problems had been largely solved in the developed world, leaving pediatrics, temporarily, with no reason for being.

The Origins of the Parent-led Schedule

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Luther Emmett Holt, MD

One of the giants of the early days scientific parenting was Luther Emmett Holt, who in 1894 published “The Care and Feeding of Children“. Originally intended as a teaching manual for nurses in New York City, Holt’s book quickly spread in popularity to the reading public. It takes the form of an extended FAQ, with questions and short answers.

The section on sleep in Holt’s book is remarkably brief. Holt’s advice is clearly prescriptive, particularly with respect to feeding and sleeping:

How can a baby be taught to be regular in its habits of feeding and sleeping?

By always feeding at regular intervals and putting to sleep at exactly the same time every day and evening.

When should regular training be begun?

During the first week of life. (p 109)

Holt may not have invented parent-led schedules, but the publication of his book gave the imprimatur of the medical establishment to the method.

The Baby-led Revolution

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Holt’s prescriptions lasted about 60 years, until the publication in 1946 of a book called “The Commonsense Book of Baby and Child Care” by a Connecticut pediatrician named Benjamin Spock.

“Trust Yourself. You know more than you think you do.” With this famous opening line, Spock fired the first shot at medical establishment prescriptions about feeding and sleeping. Spock counseled parents to trust their own instincts and to pay attention to the baby and her signals. It’s difficult to imagine just how controversial this idea was in the mid-20th century. These ideas were so dangerous to his own standing in the medical establishment that Spock couches his recommendations in extremely cautious language. In his chapter called “Schedules”, Spock begins by saying

“Your doctor will prescribe the baby’s schedule on the basis of his needs, and you should consult him about any changes. The following sections are mainly a general discussion of what schedules are all about…”

But Spock then goes on to argue, persuasively in my view, that baby-led feeding and sleeping habits pre-date “scientific pediatrics” and have been in fact the way babies have fed and slept from the beginning of time until Holt. Spock advocates an essentially baby-led feeding and sleeping schedule, and he endured a barrage of criticism because of it. He nevertheless prevailed, and until the modern resurgence of the parent-led schedule movement, Spock reigned.

The Sun

It’s human nature to see a pattern and to conclude that someone created the pattern. Such is the case with sleep schedules. By a few months of age, most babies tend to sleep and eat at about the same times every day. Some people believe that parents were essential to creation of the schedule. Not coincidentally, these tend to be people who favor parent-led methods of child rearing. Others, who favor baby-led methods, believe that the baby made the schedule.

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The rhythm

Both camps ignore the crucial role played by light. From a very early age, babies start to sleep longer at night, and to stay awake longer throughout the day. How do they do this? The light that strikes their eyes causes them to synchronize their sleep-wake cycles to night and day. We get sleepy at night and alert during the day.  All the baby needs to do to synchronize this “circadian rhythm” to day and night is to see light during the day, and to see darkness at night.

So parents and babies rely on the crucial participation of a third partner: the sun. Little babies wake up when they are hungry and then fall back asleep, but with time, they develop a circadian rhythm that is tuned to the day-night cycle. They sleep longer during the night and less during the day. The sun helps push them into a schedule, as much or more than they schedule themselves, and more than parents schedule them.

The system isn’t perfect. No system is. The schedule gets thrown off. Babies have busy days, they get overstimulated. They get sick and need more comfort. But the basic schedule remains unchanged and so do the influences that created the schedule.

How do you create a good sleep/feed schedule? The best advice I can give is to stop trying to make a schedule and allow the schedule to make itself.