Extinction sleep training is a method where you put your baby down awake at bedtime and do not respond to crying or fussing until a set wake time. The goal is to remove the reinforcement (your presence, rocking, feeding) that your baby has come to depend on for falling asleep, so they learn to settle independently. It’s sometimes called “cry it out” or CIT, and it’s the most straightforward of the behavioral sleep training approaches. A systematic review of sleep intervention studies for children under five found that extinction-based methods produced clinically significant improvement in more than 80% of children.
How It Works in Practice
The basic protocol is simple, which is part of its appeal and part of what makes it hard. After a consistent bedtime routine (bath, book, song, whatever you choose), you place your baby in their crib drowsy but awake, say goodnight, and leave the room. You don’t go back in to soothe, pat, rock, or feed until the next morning or a predetermined feeding time if your baby still needs overnight feeds.
The idea is rooted in behavioral psychology. When a baby cries at bedtime and a parent responds by picking them up or nursing them to sleep, the baby learns that crying produces comfort. In extinction, you stop reinforcing that connection. Without the payoff, the behavior (crying to summon a parent) gradually fades.
The Extinction Burst: Why It Gets Worse First
Almost every parent who tries this method encounters the same unsettling pattern: the first few nights are significantly worse than baseline. This is called an extinction burst, and it’s a predictable part of the process, not a sign that something is going wrong. When a behavior that used to “work” suddenly stops producing results, the child tries harder before giving up.
Research illustrates this clearly. In one study, babies who typically cried for 35 to 40 minutes at bedtime escalated to over 70 minutes of crying during the first two nights of extinction training. That’s a near-doubling of protest, and it’s the point where many parents break. If you respond during the burst, you’ve effectively taught your baby that extended, intense crying is what it takes to get a response, which can make the next attempt even harder.
How Long It Takes
Popular advice often promises results in three to five nights, and for some babies that’s accurate. Crying at bedtime does tend to drop off relatively quickly. But night wakings can be a different story. One study found it took three or more weeks for overnight wakings and crying episodes to drop below four per week. So while bedtime may improve fast, the full picture of consolidated sleep can take longer than many parents expect.
The wide range matters. Some babies respond dramatically within days. Others take weeks. Temperament, age, how entrenched the sleep associations are, and whether the approach is applied consistently all play a role.
When to Start
Most pediatric guidelines recommend beginning sleep training around four to six months of age. Before that, babies’ sleep patterns are still maturing, and they typically still need overnight feeds for nutritional reasons. Starting before four months isn’t recommended.
There’s also a practical window to consider. Separation anxiety typically kicks in around eight months, and training before that phase arrives can make the process smoother. That doesn’t mean it’s impossible after eight months, just that the protest period may be more intense.
Unmodified vs. Graduated Extinction
Extinction sleep training actually comes in several forms, and the version described above, with no parental check-ins, is called unmodified extinction. It’s the fastest but emotionally hardest approach. The alternatives share the same principle but soften the execution:
- Graduated extinction (often called the Ferber method) lets you check on your baby at increasing intervals, say every 5 minutes, then 10, then 15. You offer brief verbal reassurance but don’t pick the baby up.
- Extinction with parental presence allows you to stay in the room (often sitting in a chair near the crib) without actively soothing, then gradually move farther away over several nights.
All three approaches fall under the extinction umbrella, and the same systematic review found them effective. The choice often comes down to what parents can actually sustain. Unmodified extinction tends to resolve crying faster because there’s no intermittent reinforcement from check-ins. But graduated methods are easier for many parents to follow through on, which matters, since consistency is the single biggest factor in whether any version works.
Does It Harm Your Baby?
This is the question behind the question for most parents researching this topic. The concern is intuitive: letting a baby cry for extended periods feels wrong, and you may worry it causes lasting stress or damages your bond.
The cortisol evidence is reassuring. A study comparing extinction-based sleep training to gentler responsive methods measured infant stress hormones (cortisol) at bedtime across multiple time points over eight weeks. Cortisol levels measured 40 minutes after the baby was placed in their crib did not differ between groups at any point. There were no significant differences between the extinction group and the responsive group, and no significant changes over time within either group.
The longest follow-up study tracked families for five years after the intervention. At age six, children who had undergone behavioral sleep training showed no differences from control children on any measure the researchers tested: emotional behavior, conduct, sleep problems, psychosocial functioning, or chronic stress levels. Parent-child closeness, conflict, and attachment were also indistinguishable between groups. Parental depression, anxiety, and stress scores were no different either. The researchers’ conclusion was straightforward: behavioral sleep techniques produced no marked long-lasting effects, positive or negative.
That last point is worth sitting with. The five-year data suggests extinction training solves the immediate sleep problem without leaving a measurable footprint, good or bad, on your child’s emotional development or your relationship.
Why Parents Struggle With It
Knowing the research and living through the experience are two very different things. The extinction burst is genuinely difficult. Listening to your baby cry for over an hour on the first night, knowing you could stop it by picking them up, requires a level of resolve that many parents find unsustainable.
Inconsistency is the most common reason extinction fails. Going in to comfort after 45 minutes of crying teaches the baby that 45 minutes is the threshold, and the next night they’ll cry at least that long. This is why some sleep researchers and pediatricians actually recommend graduated extinction over unmodified: it’s slightly slower, but parents are more likely to stick with it.
Practical factors matter too. If you live in an apartment with thin walls, or if one parent is on board and the other isn’t, or if an older sibling is being woken up, the method may not be feasible regardless of what the data says. Sleep training works best when the whole household is prepared for several rough nights and committed to the plan.
Setting It Up for Success
If you decide to try extinction, a few conditions make it more likely to work. Your baby should be at least four months old, healthy, and gaining weight appropriately. The sleep environment should be safe: a firm mattress, no loose bedding, room temperature comfortable. A predictable bedtime routine of 20 to 30 minutes helps signal that sleep is coming.
Pick a start date when you don’t have travel, houseguests, or other disruptions on the horizon. You need at least a full week of consistency. Both caregivers should agree on the plan in advance, including exactly what “not responding” means (you’ll still go in for genuine safety concerns, illness, or a diaper blowout, but not for protest crying).
Keep in mind that the first two or three nights are the hardest, and that a temporary increase in crying is normal and expected. Many parents find it helpful to monitor their baby on video so they can confirm safety without entering the room. After the burst passes, most families see a rapid decline in both the duration and intensity of crying at bedtime.