The idea behind extinction (or full extinction to differentiate it from graduated extinction) is that you want to extinguish the behaviour (crying) by not responding to it. As with the check-and-console method, go through your bedtime routine, put them in their crib awake, say good night and walk out. This is certainly the most controversial sleep-training method, and even experts disagree on what you should do next—it all depends on what stage your baby is at developmentally, as well as what works for the parents.
It might be strange to think of sleeping as a skill that does not come naturally. As a new parent, you’re probably so exhausted that you pass out as soon as your head hits the pillow. Your baby, however, doesn’t have this same ability yet. Although they spend a lot of time sleeping, they need to learn when to sleep (day vs. night) and how to sleep. Until they do, they need your assistance, which is why you (as you should) help soothe them to sleep at bedtime and comfort them when they wake in the middle of the night. Sleep training is teaching your baby how to sleep without any help from you - just like you’re able to fall asleep without anyone there to help you do it.
As you might suspect, this method can be very difficult, depending on temperament, and can take many days or weeks. It can be difficult to avoid engaging with your child (and “watching them cry” is very difficult), and it will likely be a little confusing to the child (particularly younger ones) when you don’t. However, with time and consistency, this can be a good option for parents who do not want to leave their child alone to cry but who haven’t had success with other methods, either.
Pantley offers a gentle and gradual approach to all aspects of sleep, customized to your baby's needs. She recommends rocking and feeding your baby to the point of drowsiness before putting him down – and responding immediately if he cries. Parents are urged to keep sleep logs, nap logs, and night-waking logs. Pantley also describes a six-phase process for teaching a child to sleep in a crib.
The age of your baby might determine what kind of sleep-training method you choose, though. You could try a gentle shush-pat technique with a five-month-old, but you’ll likely have to leave a one-year-old in the crib as they protest (cry or scream) about the new bedtime arrangement. Don’t attempt a formal sleep-training method before four months, until your baby is able to go longer in between feeds and their circadian rhythm starts to develop. (Many babies this age still feed in the night—contrary to popular thinking, sleep training isn’t synonymous with night weaning.) Dickinson says that many four-month-old babies are biologically able to go through the night without a feed, but that doesn’t mean you shouldn’t respond and feed them if other methods of calming them aren’t working. Since every situation is different, we recommend checking with your doctor before withholding your baby’s night-time feeds.