I need to address something that happened on my Instagram page. After sharing expert opinions from 6 internationally recognized child development and sleep experts who advise against cry-it-out sleep training, a sleep trainer came to my comments claiming their expertise was “not valid” and “not science.”
Let me be clear: Professor James McKenna has spent 30+ years studying mothers and babies IN AN ACTUAL LABORATORY. Dr. Margot Sunderland is the Director of Education at the Centre for Child Mental Health. Dr. Helen Ball runs the Parent-Infant Sleep Lab. These aren’t Instagram influencers – they’re pioneering researchers with decades of peer-reviewed publications.
This sleep trainer then dumped 14 studies in my comments, claiming they prove CIO creates secure attachment and causes no harm. I recognized some of these studies – they’re the same ones I was given in sleep school years ago to justify CIO. Reading them critically is what made me question everything.
The crazy part? She clearly did not read through them because some of them did not exist and others were actually against sleep training! She must have been sent these studies in her sleep course and did not bother to check them!
Before we dive into the flawed studies, let’s establish who the ACTUAL experts are:
These aren’t “opinions” – this is SCIENCE.
McKenna & Ball’s Research involves:
Parent-Reported Studies involve:
Which would YOU trust?
John Bowlby, the GRANDFATHER of attachment theory, observed something crucial in hospitals:
“Children stopped crying when parents weren’t allowed to visit for DAYS. Staff thought they were ‘better’ – eating and sleeping well.”
But Bowlby recognized: THEIR DEFENSES WERE UP
This is EXACTLY what happens with CIO. Not self-soothing. SHUTTING DOWN.
What Actually Happens When Babies Cry Alone:
Neurological Impact:
The Baby Isn’t “Learning” – They’re experiencing toxic stress that can:
Babies CANNOT Self-Soothe
Self-regulation doesn’t develop until ages 5-7!
What sleep trainers call “self-soothing” is actually:
“Any uncomforted infant mammal will stop crying. It’s not an achievement – it’s resignation.” – Dr. Margot Sunderland
Now, let’s examine each of the 14 studies the sleep trainer cited to support her claims that CIO creates secure attachment and is harmless:
Citation: Gradisar, M., Jackson, K., Spurrier, N. J., Gibson, J., Whitham, J., Williams, A. S., Dolby, R., & Kennaway, D. J. (2016). Behavioral Interventions for Infant Sleep Problems: A Randomized Controlled Trial. Pediatrics, 137(6), e20151486. doi: 10.1542/peds.2015-1486
Critical Flaws:
Critical Commentary by Dr. Sarah Blunden (2016): “This paper suggests that controlled crying does not result in any detrimental impact on either the infant or the parents but I feel that the methods and the subsequent conclusions as reported disallow this assumption… I would argue that this data makes it impossible to deduct that controlled crying does or does not impact attachment or stress.”
Citation: Hiscock, H., Bayer, J. K., Hampton, A., Ukoumunne, O. C., & Wake, M. (2008). Long-term mother and child mental health effects of a population-based infant sleep intervention: cluster-randomized, controlled trial. Pediatrics, 122(3), e621-7. doi: 10.1542/peds.2007-3783
Key Problems:
Conclusion: This study does NOT prove CIO creates secure attachment or is beneficial for babies’ development.
Citation: Mindell, J. A., Kuhn, B., Lewin, D. S., Meltzer, L. J., & Sadeh, A. (2006). Behavioral treatment of bedtime problems and night wakings in infants and young children. Sleep, 29(10), 1263-1276.
This is actually a comprehensive review that analyzes 52 treatment studies, NOT a single study supporting cry-it-out creating secure attachment.
What This Review Actually Shows:
Citation: Mindell, J. A., Du Mond, C. E., Sadeh, A., Telofski, L. S., Kulkarni, N., & Gunn, E. (2011). Efficacy of an internet-based intervention for infant and toddler sleep. Sleep, 34(2), 245-252.
Critical Problems:
Conclusion: Shows that when parents stop responding, babies stop signaling. This is learned helplessness, not secure attachment.
This is a BOOK, not a research article. Given the issues with Mindell’s other research, this cannot be used as evidence for CIO safety.
Citation: Price, A. M. H., Wake, M., Ukoumunne, O. C., & Hiscock, H. (2012). Five-year follow-up of harms and benefits of behavioral infant sleep intervention: randomized trial. Pediatrics, 130(4), 643-651. doi: 10.1542/peds.2011-3467
Major Methodological Flaws:
Dr. Darcia Narvaez’s Critique: “This is an unconscionable and unscientific conclusion since there is no way that the authors studied all possible effects… You are encouraging irresponsible parenting behavior that will do great harm to children.”
This link actually takes you to “The official World Association of Sleep Medicine (WASM) standards for recording and scoring periodic leg movements in sleep (PLMS)” – NOT a study about sleep training. The importance of actually checking what you have been provided!
Citation: Blunden, S. L., Thompson, K. R., & Dawson, D. (2011). Behavioural sleep treatments and night time crying in infants: Challenging the status quo. Sleep Medicine Reviews, 15(5), 327-334. doi: 10.1016/j.smrv.2010.11.002
PLOT TWIST: This paper actually SUPPORTS the position AGAINST sleep training!
The authors:
Citation: Blunden, S., Osborne, J., & King, Y. (2022). Do responsive sleep interventions impact mental health in mother/infant dyads compared to extinction interventions? A pilot study. Archives of Women’s Mental Health, 25(3), 621-631. https://doi.org/10.1007/s00737-022-01224-w
This Study SUPPORTS Responsive Methods Over CIO:
Citation: Matthey, S., & Crnõec, R. (2012). Comparison of the effects of a behavioural sleep intervention and a social support intervention on maternal mood and infant sleep. Journal of Reproductive and Infant Psychology, 30(2), 135-149.
No access to verify this study.
Citation: Kahn, M., Barnett, N., & Gradisar, M. (2022). Implementation of Behavioral Interventions for Infant Sleep Problems in Real-World Settings. The Journal of Pediatrics, 255, 137-144.e2. https://doi.org/10.1016/j.jpeds.2022.10.038
Critical Problems:
Both studies have nothing to do with sleep training or attachment. They argue that sleep deprivation affects children, which doesn’t support using CIO.
Citation: Lecuelle, F., Challamel, M. J., Kahn, M., Mindell, J. A., Bruni, O., Claustrat, B., Anders, R., Franco, P., & Putois, B. (2025). Should you let your baby cry at night? The “no” rumor persists, despite insufficient scientific evidence with cortisol-stress measures. Sleep Health. https://doi.org/10.1016/j.sleh.2025.01.001
This is an OPINION PIECE, not research!
Major problems:
After thoroughly reviewing all the studies cited by the sleep trainer, here’s what I found:
The pattern is clear: This sleep trainer was given a list of “studies” in her training course and never verified them. She’s telling parents on my Instagram page that leaving babies to cry creates “secure attachment” based on research she hasn’t even read.
If these facts make you uncomfortable with CIO methods you’ve been taught, there’s another way! We offer certification in attachment-based, responsive sleep support that:
Professional discount available.
Trust your instincts. Your baby’s cries are communication, not manipulation. Meeting needs builds trust. This is how secure attachment forms.
We don’t need research to tell us how a baby feels crying alone. You wouldn’t leave an elderly parent with dementia crying. You wouldn’t ignore a sick partner. Why do we normalize this for babies who are even MORE dependent?
The answer is simple: babies can’t speak. They can’t tell us their experience. So we project adult needs onto infant biology.
Sleep trainers attend weekend courses, receive a list of flawed studies, don’t read them critically, then tell vulnerable parents that leaving babies to cry (sometimes to vomiting) for 12+ hours daily “promotes secure attachment.”
This shows a fundamental misunderstanding of attachment theory. There is ZERO chance that being unavailable to a crying baby for half their life promotes secure attachment. None.
This isn’t about shaming anyone. I believe most sleep trainers genuinely think they’re helping families. But good intentions don’t make misinformation okay.
Parents deserve accurate information to make informed decisions. When someone cites studies they haven’t read to support methods that go against every parental instinct, we need to speak up.
Read the studies yourself. Ask questions. Your baby’s emotional wellbeing depends on it.
Remember:
Let’s raise the standard together. For the babies. 💕
If you’re a sleep coach feeling uncomfortable with what you’ve been taught, know that we have a certification program and professionals discount. We never use sleep training and achieve the same results while honoring attachment and infant mental health.
#SleepTraining #CryItOut #AttachmentTheory #InfantMentalHealth #SleepScience #ResponsiveParenting #InfantDevelopment #SecureAttachment #ParentingScience #BabyBrain #GentleSleep #NightParenting #EvidenceBasedParenting #SleepCoaching #InfantSleep
