I haven't done any proper research, neither any meta research on this - it's mostly based on personal experiences. I believe this subject eventually deserves more research.
My personal belief is that it's best for the child is to never use paper nappies, use textile nappies when needed, change often, and start some sort of "potty training" already when the child is new-born. While this for sure won't save one from horrors like depicted on the painting below, I'm quite sure it will save one from some of those situations. (Since the painting was made, we've gotten running water, hot water on the tap, wet wipes, showers and water closets, plastic bags, paper nappies, liquid soap, laundry machines ... while all those things may help a bit, I still think it can be quite horrid when the baby has produced brown, sticky, stinking goo, and spread it all over the place).
We have four children. We're no super-parents, we do have limited capacity, and we're living in a society where everybody is using paper nappies ... whatever we do at home may be messed up big time when the children starts in kinder garden (and school). We do try to use textile nappies frequently, but in the end of the day we're quite dependent on paper nappies.
One of our children stopped using nappies shortly after he was one, that's our success story. Our youngest is 9 months old and is still using nappies, I hope to wane him off before he starts in the kinder garden.
Hypothesis 1: children are born with some relevant instincts
Alternative hypothesis: infants are able to learn some tricks at a very young age.
I do believe that (most) children already as a newborn or at a very early age has some relevant skills, like:
- being more likely to do their things when getting certain cues (i.e. being dressed off, held by the thighs in a squatting position, hearing certain sounds)
- holding longer when being dressed than when being naked
- giving certain signals before doing their things
With my infants, every time I change the nappy, I also give them the chance of doing their toilet business in a non-messy way; I hold them over the toilet by the tights in a squatting position, tell them to do their stuff and wait a bit (and when they are old enough, I try using the potty). Frequently they will empty themselves while I hold them like that. The children have been very different, but most of them have responded well.
Of course, there is a chance that it's purely by coincidence - toilet events happen quite frequently at that age, hold the child for long enough and for sure sooner or later something will happen - but I strongly believe there is a correlation. I haven't made any systematic statistics, but for my youngest (now 9 months) I think that in 3/4 attempts the child is peeing within half a minute when I hold him like that, and sometimes he's shitting too. (I'm very happy with the latter, as it may save me from a lot of mess).
We have local health checkups every now and then, they measure the weight, and the baby should be completely undressed. Once I got advised by the employee to hold a textile in front of our son for protection, because "they frequently pee after they have been undressed". Yes, really ... of course they do! I had just been with him to the toilet to allow him to do that, so ... I did not consider it much of a risk.
As for the last sub-hypothesis - that infants does give some signals before they do stuff - this is based on rumors and not personal experiences. Perhaps it's due to the lack of super-parent powers, perhaps it only applies to some infants and toddlers and not mine, or perhaps the sub-hypothesis is just wrong. I've heard some say early "potty training" is more about parent training than training the infant. I'm not picking up those alleged cues quickly enough, but if we would not be using nappies at all we'd probably be in a completely different situation. Instant feedback, and we'd probably have much faster reaction times (both because we had to, and because we probably would have some sort of receptacle stand-by in the living room rather than taking the infant to the bathroom and spending time taking off trousers and nappies).
Hypothesis 2: it's possible get most children "dry" before they are one year old
If the parents have sufficient capacity and skills, it's possible to build on the instincts mentioned above and get the children dry at an early age. If the parents (like most Norwegian parents of today) insists that everything should go via the nappy, then the children learn to do it that way, and the opportunity for early training is lost.
As of 2019, the average Norwegian thinking is that children should stop using nappies the summer in the year they turn three (potty training in the winter time in Norway is quite hard - it's quite strict norms in the kinder gardens that the children should be outdoors a lot, and while being outdoors the children are typically dressed in such a way that potty training is very impractical), it seems that those thoughts are based on research done by Thomas Berry Brazelton, who advocated late and slow potty training and claimed there is no point at all i starting potty training prior to the age of 18 months. So in Norway today, potty training is commonly introduced only when the child is above two, many people in Norway think there is no point even trying earlier. The common saying is that they have no control at all of those processes prior to that age. Trying to teach the kid things it isn't physically able to do will most likely backfire. Brazelton has been working as a consultant for Procter & Gamble, and even been appearing in a Pampers commercial - I do believe his research has some bias to it.
If my first hypothesis is right, then at least the idea that infants and toddlers below two "have no control at all of those processes" is either wrong, or perhaps just irrelevant. As said, we do have one anecdotal evidence, one of our children stopped using nappies indoor in the kinder garden shortly after turning one (that's before the 18 months absolute "age limit" for starting with potty training, suggested by Brazelton), and I've also heard from a colleague that his son stopped using nappies even before turning one. The adults in both kinder gardens were very much surprised, they thought it was impossible!
It's also relevant to check on other cultures where nappies aren't being used and other historical times, where good nappies haven't been available. My guess is that when nappies aren't being used, the children stop making a mess at a much earlier age. Like in China, even though paper nappies are becoming normal there, the tradition has usually been to have a hole in the trousers so the baby quickly can do it's stuff without messing up the clothes. According to Wikipedia a skilled caretaker will notice when the baby needs to do their stuff, so that they can hold it over a toilet or other receptacle, avoiding to mess up the environment. (When does a typical Chinese baby get dry?)
Hypothesis 3: Children using nappies may learn strange toilet patterns
When peeing into a paper nappy, it may be smart to pee little by little, letting the absorbents in the nappy soak up the liquids before releasing more. I do believe many users of paper nappies eventually learn to do this. I think I've seen this pattern in some of my kids:
One having frequent accidents after stopping using nappies. The normal is that the child releases everything when having an accident, but this child was "leaking" just a small amount on every accident.
One of them had a period over a couple of months with big problems, needing to pee like every 15-30 minute. Mundane things like taking the metro was really a problem. I don't know if it's related to nappy usage, but could be.
Our youngest ... I usually get him to pee into the toilet when I'm changing on him, but it seems to me that he's often stopping, without completing. Sometimes he can bee a little bit more after some seconds pause.
Hypothesis 4: Some children get so used to doing their stuff in the nappy that it's difficult for them to learn to do things in the potty or toilet
I've observed one boy that, on the age of 3, denied shitting in the appropriate place. Whenever he felt the urge, he would sneak away, find a private place and do it in the nappy.
On a related note, I've seen much older boys that have been unable to do their number one out in the nature, without a toilet. This may be for other reasons though.
Requirements for becoming "dry"
To become dry, the child needs those abilities:
Being able to do stuff on "command" or on a trigger. I think we have relatively good routines on this, offering them the choice of doing their things when we change on them, and we have had some success on this with all our children.
Being able to hold on the absence of such triggers. This is much more difficult. The infants and toddlers have a tendency to empty themselves on a whim. Using textile nappies may possibly help teaching the child that peeing while being dressed is a bad idea, as they become less comfortable once they get wet. However, they need to be changed relatively often - if they are not changed frequently, the normality will be wet nappies, and the potential to learn is somehow lost - and the child needs the opportunity to do his stuff in an orderly manner frequently.
Being able to communicate that one has toilet needs. Here the most difficult learning may possibly be at the parents side - learning to understand subtle signals given by the infant or toddler. For Brazelton and others it's a requirement that the child has a minimum of verbal communication skills before one starts with potty training.
Completing the toilet mission. As said above, it seems to be a problem sometimes that they pee just a little bit and stops.
Holding throughout a night, or eventually waking up to do toilet visits in the middle of the night. Infants tend to wake up in the middle of the night, but I guess very few parents try to allow the infant to do toilet visits in the middle of the night. I suppose the very most parents (at least in Norway) see no use of that, it may also require quite some energy from the parents. Some children struggle with it and uses nappies night time several years after they have gone otherwise "dry", some may "leak" during the night time even well into school age - perhaps the risk could be reduced through training on night time toilet visits while the child is an infant?
Elimination communication on Wikipedia.
Arbritrary images from Wikimedia Commons have been used in this post: