Today we’re going to address some common claims of sleep training. Before I get into it though, it’s important to establish a few things.
First, I address claims of sleep training to inform, not to judge or shame parents who choose it. I am pro information and informed choice when it comes to parenting decisions like this.
Second, my concerns about sleep training and the sleep training industry are myriad but can be roughly boiled down to:
The pathologisation of biologically normal infant sleep and feeding patterns
The invalidation or dismissal of infants’ and children’s genuine emotional needs
The predatory marketing sleep trainers employ via misinformation and fearmongering like “sleep training is giving your baby the gift of sleep”, “if you don’t sleep train, your baby will never learn to sleep independently”, "feeding to sleep is a bad habit", etc.
The lack of education and knowledge about normal infant sleep and feeding and lack of information around evidence-based alternatives.
The lack of adequate support experienced by parents in society today is also a large factor that cannot be ignored. While not the point of this post, I am not ignorant, naïve, or unempathetic to the situations that drive parents toward sleep solutions, including sleep training.
Whatever the reason someone chooses to sleep train, parents are doing their best with the information they have. Sleep training is the expectation, not the exception, and parents are not given adequate information about its relative risks as well as benefits. It is treated as a non-event. Just something you do on your parenting journey. My goal here is to educate. What you do with the information and how your parent is your choice, but you deserve accurate information.
What is (and is not) sleep training?
First, the term “sleep training”, and what counts as sleep training can be confusing to some. To clarify, I consider sleep training to be any method that has the goal of modifying an infant’s sleeping patterns through methods that involve any form of limiting or removing responsiveness. Such as, traditional “unmodified” extinction methods like CIO (cry-it-out), “modified” CIO (aka Ferber or controlled crying), as well as “gentle” methods (such as “camping out” or “pick up put down.”)
Although the exact details and instructions vary, what these all have in common is that they rely on parent-led limiting or complete withdrawal of responsiveness with the goal of changing sleeping behaviours and permanently removing the need for support to sleep.
They all also tend to make promises about “independent sleep”, “sleeping through the night”, etc. If any method promises such things, it is sleep training, regardless of whether it is labeled or sold as such.
The following are techniques or approaches I do not consider to be sleep training: implementing or tweaking routines and timings, changing sleep associations or “layering” of sleep associations. Additionally, some more specific strategies like “bedtime fading” that do not involve limiting responsiveness. Although these techniques are often used alongside sleep training, or lumped in in the literature on this topic, they can be implemented to improve sleep while remaining fully responsive to your baby’s needs. Therefore, they could be more accurately described as “sleep optimisation” or “sleep hygiene.”
So, now that’s all out of the way, let’s get into it
1. “Sleep training teaches babies to sleep”
This part is straightforward to answer. According to parent reports, yes, their babies sleep better and wake less after being sleep trained (H. Hiscock & Wake, 2002; Kempler et al., 2016). But parent reports are a very limited and flawed way to gather this kind of information.
Studies using actigraphy (sleep monitoring technology) tell a different story. This objective form of sleep measurement clearly shows that sleeping patterns are not different in babies before and after being sleep trained or compared to babies who are not sleep trained (Galland et al., 2017; Hall et al., 2015; Kempler et al., 2016).
Sleep training not changing sleep makes sense because sleep is a biological function controlled by sleep-wake rhythms present from early infancy (Blumberg et al., 2014); not a skill you learn or are taught.
Parents think their sleep trained baby is sleeping better because they do not signal anymore when they rouse or wake between sleep cycles. Some might say this is still a good thing; that even if sleep training doesn’t teach sleep, it does teach “self-soothing” or “independence”. So let’s talk about that next.
2. “Sleep training teaches babies to “self-soothe””
As far as research goes, there simply isn’t any evidence to support the claim that sleep trained babies are self-soothing. Zero, zilch, nada, none. Seriously.
Self-soothing was a term coined in the 1970s to differentiate from indicate the opposite of signalling. A baby who did not signal was termed a “self-soother”. It was never intended to be used the way it is today or implied you could teach this to a baby through sleep training.
The “evidence” that sleep training teaches self-soothing is based on sleep trained babies’ behaviour, i.e., they don’t appear to be distressed anymore. The issue is with claiming this is evidence of “self-soothing”. Outwardly observable behaviour, particularly that which is borne out of explicit behavioural conditioning, is not necessarily accurately reflecting what is going on in the brain. The cessation of signalling cannot and should not be used as evidence to infer that sleep training has taught a baby to “self-soothe” or emotionally regulate.
Without any evidence to show the effects of sleep training on the development of self-regulation, another way to investigate this claim is to look at what is known about the infant brain, learning, and emotional regulation development.
The brain parts necessary for emotion regulation are still developing into adulthood (Zimmermann & Iwanski, 2014). Which begs the question, how could we possibly teach this skill to an infant? These are complex higher cognitive functions we are talking about. Expecting an infant to be able to learn to self-regulate at 6-months old is a bit like expecting them to walk or read a book. It’s just not a realistic or age-appropriate expectation.
Additionally, we know enough about how skills, including emotion regulation skills are learned to know that skill-learning does not happen through separation, isolation, or in a state of distress.
For example, a well-established way that children learn is through Bandura’s social learning theory or modelling. Applied to emotion regulation this means your baby watching you self-regulate repeatedly models the behaviour and assists with their learning. Another is through scaffolding, which involves guidance from a more experienced person (Vygotsky, 1967).
Another crucial aspect of regulation development is co-regulation, i.e., the physiological shared experience that involves you, a calm regulated caregiver, being attuned to and meeting the needs of your baby and “sharing your calm”. The physiological process of their nervous system downregulating in response to yours teaches their brain through experience and is something humans need in early life and through young adulthood to develop effective self-regulation skills and social emotional skills more broadly.
You will notice that none of the established ways of developing the skill of emotion regulation involve limiting responsiveness or leaving a distressed baby alone. There is simply no evidence or even plausible theory for how sleep training or reducing access to the single most important feature needed for learning (you!) could teach or assist with infant development of emotion regulation.
Further evidence that sleep training does not teach emotion regulation is that it only “works” for the period of time the parent actively employs the methods of not responding. If the infant is attended to at night again (e.g., when they are sick or some other disruption in routine occurs), they very quickly begin signalling again. A truly learned skill by a person developmentally ready for that skill is not unlearned. This is very good evidence alone that sleep training is only changing behaviour, not teaching a skill.
3. “Your not sleep trained baby is sleep deprived, and long stretches of sleep are necessary for their development”
Well, this is an interesting one. It sounds pretty logical, right? If you struggle to get your baby to sleep according to the common guides out there, you might have convinced yourself they’re sleep deprived. And sleep is important for our health and development. But let’s break it down.
First, that long stretches of sleep are needed for a baby’s healthy development. Put simply, babies are supposed to wake, and there is no evidence that normal infant sleeping patterns (which are fragmented by nature) in a healthy baby is detrimental to development, and evidence supports this (Pennestri et al., 2018). Second, given sleep training does not change sleep (Galland et al., 2017; Hall et al., 2015; Kempler et al., 2016), how could it be expected to positively affect development via improved sleep? The improved sleep would need to be occurring for this idea to have any merit. So, the claim that “Long stretches of sleep are necessary for healthy development”, is also not evidence based.
Note: excessive waking can be caused by issues with circadian rhythm or sleep pressure, or be a medical red flag e.g., for a breathing disorder or low iron. Excessive waking should be investigated for root cause and sleep training would not address any underlying reason for excessive waking. Be aware of any person who suggests a behavioural solution for a physiological issue – that is a red flag.
4. “Sleep training improves parent mental health”
There is some limited evidence for this claim. But does it stand up under scrutiny? While a small positive effect of well-being with sleep-training has been found (Kempler et al., 2016), other research suggests parents find sleep training stressful (Loutzenhiser et al., 2014). Those instructed to implement sleep training methods often drop out, with parents citing reasons such as experiencing stress and anxiety and that they believe sleep training caused their baby stress too (Loutzenhiser et al., 2014).
One study finding improved well-being after sleep training was in the context of a peer-support Facebook group (Honaker et al., 2018) which could have had an influence. Indeed, other research has reported that giving a mother someone to talk to was more effective and longer lasting in reducing reported sleep problems than sleep training (Hiscock et al., 2007). This suggests support has a positive effect independent of sleep training and may indicate inaccurate interpretation in other studies that did not tease apart or control for these factors.
I know this is a long one so bear with me. To summarise, we know:
Sleep training does not affect infant sleeping patterns, so could not cure any kind of genuine sleep problem if one even exists
There is no evidence that sleep training teaches self-soothing and a lot of evidence that indicates responsiveness is necessary for development of emotion regulation
There is no evidence that normal fragmented infant sleeping patterns negatively affect development
There is very limited and mixed evidence about the effects of sleep training on parent well-being and it’s possible increased support would achieve the same goal.
Risks of Sleep Training
I think we can safely say that the most popular claims of sleep training are not evidence-based. But I think it’s also important to talk about the common that even if sleep training doesn’t “teach sleep,” maybe it isn’t harmful either.
Is this true though? The “best” evidence we have that sleep training is not harmful is deeply flawed. One longitudinal study gathered data over a five-year period and reported they found no link between sleep training and social emotional outcomes (Price et al., 2012)
There are several issues with this research that make conclusions of a lack of harm difficult, if not impossible to draw.
First, the study used mainly parent reports which are not a reliable measure. Any number of biases can influence parent report and additionally a parent that sleep trained may hold bias toward not acknowledging potential negative effects.
Second, while a five-year follow-up study sounds like a long time and is indeed the longest follow up study in this area, most mental health issues do not emerge until much later, i.e., adolescence and beyond.
Third, and possibly most importantly, they didn’t know who sleep trained and who didn’t. As in, this wasn’t a truly controlled experiment. At around 7-10 months old the “intervention” group simply received education about sleep training with a nurse trained by researchers to give sleep training advice, whereas the “control” group received education from a nurse not directed to give sleep training advice. The control group could still ask for sleep advice though and given this study occurred in Australia, the nurse likely would have been generally trained to provide sleep training advice and likely did (they were not told not to). The parents in either group could have received sleep training advice via various other avenues outside the study as well, and the researchers never confirmed who implemented the sleep training and who did not.
Essentially, the groups did not necessarily differ in any meaningful way in terms of their approach to sleep so it is impossible to draw conclusions about outcomes by comparing them and it is unsurprising there was no differences found.
There are several potential tangible ways sleep training could be harmful
Early cessation of breastfeeding.
Sleep training (often started as early as 4–6 months old) usually involves full or partial night-weaning. This can be detrimental to supply and, particularly if in combination with working away from a baby during the day, can lead to loss of supply and early complete weaning. Most mothers are NOT warned of or aware of this when commencing sleep training.
Increased risk factors for SIDS/SUDIs
Separate room sleep significantly increases the risk of SIDS & SUDIs in the first 6-12 months which is why peak bodies such as the AAP and Red Nose Australia agree that infants should sleep in the same room as a caregiver for all sleep during this period, including night sleeping and naps. Sleep training usually involves placing the baby in a separate room to sleep for it to be “effective,” which statistically increases their risk.
Risk of harm to brain development
This is a very complex area, but maternal and paternal responsiveness have been found to have a buffering effect on the developing stress systems in the brain and lead to better self-regulation skills observed at preschool age (Abraham et al., 2021; Gunnar & Ph, 1998). Evidence in this domain is essentially non-existent, but it is conceivable that non responsive sleep training could present a significant opportunity loss that could reduce this buffering effect and ultimately hinder the development of emotion regulation.
Final thoughts
It is important to say as I wrap this up that it is likely that a variety of factors including genetic profile, temperament, and other environmental influences that would determine whether sleep training would harm an individual. Even if this is true though, and it doesn’t harm all babies, there are still big problems. First, we can’t very accurately assess risk profile. Second, what is an acceptable level of risk? And third, do the ends justify the means - does a baby turning out “fine” justify the use of non responsive techniques that cause distress?
With several evidence-based alternatives, I would argue that in most cases there is a safe, responsive, alternative that supports both an infant’s and the parent’s sleep and mental health.
If this information has caused you distress in any way because you have sleep trained your child, please be gentle with yourself. You are not alone, in fact I have been there myself. Know that repair is always possible through ongoing warm and responsive caregiving.
If you need sleep support, you can find my support options here and a number of on demand courses and guides for infant sleep, toddler sleep, and night weaning
Jess
Infant Sleep Scientist
References
Abraham, E., Zagoory-Sharon, O., & Feldman, R. (2021). Early maternal and paternal caregiving moderates the links between preschoolers’ reactivity and regulation and maturation of the HPA-immune axis. Developmental Psychobiology, 63(5), 1482–1498. https://doi.org/10.1002/dev.22089
Blumberg, M. S., Gall, A. J., & Todd, W. D. (2014). THE DEVELOPMENT OF SLEEP-WAKE RHYTHMS AND THE SEARCH FOR ELEMENTAL CIRCUITS IN THE INFANT BRAIN. Behavioural Neuroscience, 128(3), 250–263. https://doi.org/doi:10.1037/a0035891
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