Another very common change in "context" that is oftentimes overlooked is the onset of new motor skills, most notably rolling over, crawling, and walking. All these fabulous physical milestones change the way your baby sees the world in fundamental ways. Here's one of many similar questions I've received:

I just received your book and found out that we are now entering a good
sleep training phase since my son turns 1 this coming Friday.  I want to get
him to start falling asleep on his own, but if I try to put him in his crib
while he's only half asleep, he just stands right up like he's on automatic
pilot.  If I then leave him he starts to cry and I don't want to use any of
the CIO methods. Besides, that doesn't work with him because it just
escalates into a frenzy. I still have his crib in our room and want to get
him into a firm sleep habit before trying to move him into his own room. I
can't figure out how to get him to relax though….

This is a classic age when SOME kids have a hard time falling asleep. And it has a lot to do with the new motor skills they're learning and practicing — namely walking. About the 12th month mark is when many kids start learning to walk and all hell can break loose with their sleep habits because their little minds and bodies are furiously practicing. By the way, children can start walking as early as 8 months (oh… I pity the parents that have to deal with those little daredevils) and as late as 18 months with no long-term benefits or problems. When we watch people do things, even if we are currently not doing them ourselves, a fascinating thing happens in our brains. The same pattern of neurons fire whether we're watching someone move their arm , for example, or if we ourselves are moving that arm. This  fascinating discovery is considered by some to be the most important one made by neoroscientists for decades –  "mirror neurons." So it may be that when children are watching others walking and when they are put in their cribs alone, what they are doing is not only moving their feet, poppinp up and down holding the bars of the cribs, cycling their little legs, and so on. They are also probably imagining the act of walking — both when they're awake and asleep, dreaming. This may be why many kids' sleep is disrupted as they're at the cusp of mastering physical skills. There are no direct studies that have mapped the neuronal activities of babies asleep in their cribs when they're just starting to walk, but that would be my strong hunch of what's going on.

The same holds true of the other major physical milestones — they too have the potential to disrupt sleep. So, rolling over (around 5-6 months), crawling (around 8-10 months) and walking (around 12-14 months) may be difficult times for sleep training also (Again, please keep in mind that these age-spans are approximate. My kids didn't hit any of these milestones "on time" if that matters to anyone). And remember the title of this post was supposed to be the continuation of Part I and Part II about how context can have an impact on sleep-training or can disrupt already well-established sleep habits. The reason this post is also about context is that when children learn new motor skills their WHOLE WORLD is blown apart. So many of the most important parts of their contexts undergo radical changes. The baby that can suddenly roll over begins to feel the wonder of intentionally changing their body posture, their view, their physical feeling of how the exist in the world. The baby who can finally crawl finally feels the incredible miracle of being able to reach and chase stuff that's so far been out of his reach. The baby who previously had to point or squak to get you to get her some toy across the room can now DO IT HERSELF!  YIPPEEEEE! Now mulitply that miracle by 100 when walking begins. Oh how fast he can now move to the desired object! How much fun it is to hurl yourself onto couches and into grass and to push, push, push chairs and tables and plastic lawn mowers and so, so much more. The world around these babies is indeed changing dramatically and, as we talked about before, these shifts in contexts can have a major impact on sleep (as well as moods and thinking styles… but that's another post).

Um, yeah, remember I said that I had a bunch of posts in the hopper waiting to be automatically uploaded at regular intervals? Well that didn't work as well as I had planned, did it? I have no idea what happened, but it seems that nothing has yet been posted. Sorry… and onward.

I am currently travelling with our two lovely but CRAZY three-year olds. Crazy in that they are completely unpredictable. We flew overseas and of course I was sure they'd eventually SLEEP overnight. You know, on that OVERNIGHT flight?! They did not sleep ONE WINK. How does that happen? They were up until 2 am and they seemed permanently set on party mode. I was convinced that the rest of our trip would be fraught with sleep HELL. I certainly was prepared to be up ten bajillion times per night as they adjusted to being jet lagged. And yet, for the first 3 nights of our trip they've slept 14 hours straight through the night, 13 hours and 12 hours, respectively. Go figure… I don't know why any of you listen to me. I have NO IDEA what's up with this sleep stuff. But enough about me let's move on to the reader's question:

Great questions. Let's start with question #1: The short answer is, yes. Timing ANY big transition is best done outside of the sensitive developmental windows. As you may have figured out by now, I think that the developmental transition periods are periods of vulnerability during which children are sensitive in general and changing any established habits — including, but not limited to naptimes and bedtimes — are more difficult during these stages. Extending this idea, I actually think that events such as potty-training, entering a new daycare, changing caregivers, and weaning could best be done (IOW, more easily and with less distress) outside of these sensitive developmental stages. But returning to the specific question, being "all done" would be ideal, but of course circumstances in our lives usually don't align themselves perfectly with optimal developmental timing. All we can do is to try to time things as far away from these ongoing sensitive periods; but remember, these ages are approximate and you've got a little leway on both sides of the ages spans we talk about here (and in the book).

In terms of the second question, yes, the dirty little secret that very few people talk about is that MOST of us have to sleep-train our children more than once. Illness, travelling, a new sibling, moving houses, and parents going back to work (or changing hours) may all be reasons why hard-won sleep habits can disintegrate and sleep-training efforts will need to be renewed. From our experience with our own children and hearing many stories from countless parents, I DO believe that the subsequent sleep-training efforts are usually more easily implemented and cause generally less distress for the whole family. BUT THIS IS NOT BASED ON ANY RESEARCH EVIDENCE. I need to be clear about what I have a strong feeling about, based on experience and anecdotal evidence, and what is backed up by empirical evidence. Also, we may have to use different methods at different
developmental stages. For example, I think straightforward Ferberizing
can work quite well for some children around 6 months or so, but 3
year-olds are not going to be easily "Ferberized." So not only do we often have to sleep-train a few times, but we may need to be flexible with the methods that will be most effective over these repeated efforts.

So back to the second part of question #2, I think that sometimes, if kids have already learned to put themselves back to sleep at one time, when those habits get shaken up (by illness or travel, for example), you can "remind" kids how to do it, even during developmental transition periods. This is because these "booster" sleep-training sessions may not trigger the same sorts of fears of loss, anxiety about the "unknown"; basically, they may not be loaded with the same intense emotions the second, third or fourth time. So, if I were you, I would TRY to re-train as soon as you get back from all your travelling. Implement your preferred sleep-training method for a few days and if after 3 days or so things don't start improving, then you may indeed want to wait for a couple more months. But you may be surprised by how easily your baby "remembers" the skills she learned so well a few months ago. 

Enjoy your time away, good luck with the "re-training" and keep us posted with how it goes. Because there are no systematic studies on this exact topic, I am genuinely interested in whether this advice is sound. Anyone else have any datapoints a la Moxie? Any other parents have experience with sleep-training multiple times? Was it easier each consecutive time? Did it depend on what age you were "retraining"? I'd love to conduct a study on this…