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6 Hidden Myths Behind Baby Sleep Training Advocacy

Beware the biases against babies.

Key points

  • Studies have shown that babies are not “fine” when they stop crying.
  • Babies expect constant caregiver presence and need an external womb experience until at least 9 months old.
  • If parents succeed in making their baby not need them to be present, then damage has been done.

Ignorance about baby needs fuels adult mistreatment of them, with ramifications on their health and wellbeing, social and moral capacities for the long term. Such ignorance leads to myths that adults believe and apply, in part because they don’t have their own experience and they’ve been taught not to follow their instincts. Ignoring baby needs perpetuates the cycle because the babies become adults who don’t have well-shaped emotions and instincts to guide their behavior. They have to rely on experts to “know” anything. And much of that knowledge is unwise, small-picture, based on misconstrued studies.

What are the mythical assumptions behind using cry-it-out (total extinction, unmodified extinction) or even controlled crying (graduated extinction) sleep training to get babies (0-2 years old or so) to sleep on their own? Here are several.

Myth 1: Isolating babies is not harmful to them.

This is the notion that if you cannot see it, nothing bad is happening. On the contrary. Baby mammals, like humans, are meant to be physically on or next to caregivers 24/7 until they themselves choose to move away. Babies have many needs.

There are lots of animal studies (and observations) on the needs of mammalian babies for parental presence. (And remember that human babies need much more than rats or mice.) For example, Hofer (1987, 1994) examined physiological regulation in rat babies (who are much less social than humans) and has demonstrated that separation from the mother causes dysregulation in multiple physiological systems like breathing, heart rate, hormones. Schanberg (1994) showed that growth slows down when rat babies are separated from their mothers. In humans, we cannot do experiments but can see effects of extreme neglect in children’s brains where the brain slows its growth of networks and communication pathways scheduled to come online at those particular times.

Compared to rats, humans have much more of a brain to develop. At (full-term) birth—humans have 75 percent more of the brain to grow (90 percent by age 5!) (Trevathan, 2011). So the animal studies give us only a hint at how early experience can affect development—the way human babies are treated by caregivers has even more effects on them than for any other animal because they are born so immature.

We have massive mental health problems in the USA and other advanced nations where babies are routinely isolated and distressed. There are even now specialists in baby depression! (See more information here and here). Babies can get depressed when they are physically isolated from caregivers (not held). Poor sleeping and eating, or lack of expression can be signs of depression. Sleep training to force them to sleep alone can exacerbate depression.

Sure, it is possible that these babies have inherited epigenetic imprints from their parents’ experienced distress, but it is more likely that their own experience has made them depressed. Animals studies show us that regularly separating a baby from the mother alters the brain (the first 10 days of life for rats is comparable to the first 6 months for human babies).

Myth 2: Putting babies into a distressful situation is not harmful to them.

Extended stress destroys tissues in mammals, impairing organ function and health (Kumar et al., 2013). Isolation is distressful for rat and mouse babies and has all sorts of ill effects like disorganizing stress response systems and undermining the expression of genes that control anxiety (McEwen, 2003; Meaney, 2001). The effects are much greater for humans. Leaving babies to cry unaided is highly distressful and physically and psychologically toxic.

Imagine being in an extreme panic attack but your best friend locks you in a room alone while saying, “Never mind, you’ll be fine." how would that affect the trust you have for that friend? Your relationship will be forever changed. Babies, of course, don’t understand any of this but feel deep panic and will shut down when stress goes on too long.

It is true that most research studies examine extreme cases of abuse or neglect. Why? Because:

  • The damage of extreme neglect or abuse has already been done and a control group of uninjured humans can be compared. (In other words, it is unethical to set up these types of experiments.)
  • Because we cannot set up ongoing experiments of neglect, we cannot see how it affects ongoing brain development at critical points of maturation for a particular system.
  • Current measurement tools are unable to provide detailed effects since we still know very little about brain function.
  • Most brain studies don’t determine how normal the brains being studied really are (how were they developed?) so we don’t have a baseline for optimal development for comparison. Contrasting today’s “normal brains” against abused/neglected brains is unlikely to be testing optimality vs suboptimality. Instead, it’s looking at different types of suboptimality (since these days very few babies and young children are provided with what they need).

Myth 3: The baby does not need to be with a caregiver at night.

Babies need adults to learn self-regulation from the presence of caregivers. Period. Leaving a young baby alone can dysregulate development in small or large ways depending on many factors. Without an adult presence, a baby’s self-regulatory systems may not be developed properly and can be undermined. Dr. James McKenna’s research demonstrates how important the presence of the caregiver is for baby self-regulation.

Myth 4: Babies must be taught to be independent.

It takes several months for babies’ brains to grow into the understanding that when an object is out of sight, it still exists. (This is called object permanence.) Just think, when parents are not present, the young baby has no sense that they might be nearby. For that baby, they are gone—out of sight/out of feel. Young babies have no sense of anyone unless that person is sensed right there. So when a baby is left alone, it would be normal for a baby to have a severe stress reaction with a fight-flight reaction. But babies cannot move so they are stuck, unable to run to the parent for help (which we all know they would do if they could).

If this mobilizing reaction goes on too long, the baby’s body has to downshift to a self-preservational mode. It turns into a freeze-faint reaction where the body slows down to preserve its life, slowing down energy use and growth. The baby will look catatonic. It’s strange adult logic that thinks this is good for the baby. Too much or too many times of this experience will have an effect on trust, and health (and morality).

Myth 4: Good babies sleep through the night.

No one, not even adults, sleep through the night (Bonnett & Arand, 2007). (See more about sleep here). Adults often don’t realize that they wake up periodically throughout the night. They just tend not to panic, unlike a baby would, who needs and expects caregivers nearby.

Babies are growing rapidly, thousands of synapses being created a second—why would we want to interfere with this scheduled development? Babies require support like an external womb to keep them growing till 9 to 18 months old when they start to resemble the newborns of other animals. When babies wake up they need to feel safe and secure so that growth continues. If they go into a panic state, they slow down growth and increase distrust in their own needs and the supportive nature of the world. Think of how this undermines emotional intelligence.

Myth 5: When babies stop crying, they are fine.

Wendy Middlemiss and colleagues (2012) have shown that babies are not “fine” when they stop crying (even though parents may feel great). A baby learns not to signal their needs if caregivers ignore them. Some might think this is good (don’t bother me, baby!) but it really is not good unless you are trying to raise a person with limited social skills, self-awareness, and social motivation.

Like isolation, crying in babies undermines growth and development because it creates toxic stress and for brain/body systems (and psyche!).

Myth 6: Sleep training studies can inform us about long-term effects on child wellbeing.

Most sleep training research studies whether an intervention is effective at shutting down the baby so parents get more sleep. These studies typically do not study effects on baby development and wellbeing. The studies often use a standard of “intent to treat” where they even don’t monitor what the comparison group is doing. So there is no way to reliably gauge what a baby has really experienced. As a result, even when they measure an outcome, it is unreliable and limited in trustworthiness.

Bottom line for babies: Babies evolved to need an external womb experience till at least 9 months (due to immaturity at birth and rapid epigenetic growth after birth). They expect constant caregiver presence. They should not be distressed while the brain is developing rapidly or there may be long-term ramifications.

Bottom line for parents: Babies need the constant presence of caregivers. It’s best that parents figure out a way to reshape their lives around this need. If parents “change” a baby to not need them present, then damage has been done.

Bottom line for researchers and medical personnel: Take the mammalian baby baseline seriously and use a precautionary principle. Only make recommendations to go against 30 million-year-old practices if you have high-quality longitudinal (10-60 years), multivariate analyses of relevant wellbeing variables. Barring this, help parents and communities figure out ways to meet babies' needs (as well as the needs of parents).


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Hofer, M.A. (1987). Early social relationships as regulators of infant physiology and behavior. Child Development, 58(3), 633-647.

Hofer, M.A. (1994). Hidden regulators in attachment, separation, and loss. In N.A. Fox (Ed.), Emotion regulation: Behavioral and biological considerations. Monographs of the Society for Research in Child Development, 59, 192-207.

Kumar, R., Kumar, S., Ali, M., Kumar, A., Nath, A., Lawrence, K., Singh, J.K. (2012). Impact of stress on histology and biochemical parameters of liver and kidney of mice. Innovative Journal of Medical and Health Science, 2, 63 – 66.

McEwen, B. S. (2003). Early life influences on life-long patterns of behavior and health. Mental Retardation and Developmental Disabilities Research Reviews, 9(3), 149–154.

Meaney, M. J. (2001). Maternal care, gene expression, and the transmission of individual differences in stress reactivity across generations. Annual Review of Neuroscience, 24, 1161–1192.

Middlemiss, W., Granger, D.A. Goldberg, W.A., & Nathans, L. (2012). Asynchrony of mother–infant hypothalamic–pituitary–adrenal axis activity following extinction of infant crying responses induced during the transition to sleep. Early Human Development, 88 (4), 227-232.

Schanberg, S. (1995). The genetic basis for touch effects. In T. M. Field (Ed.), Touch in early development (pp. 67-80). Mahwah, NJ: Erlbaum.

Trevathan, W.R. (2011). Human birth: An evolutionary perspective, 2nd ed.. New York: Aldine de Gruyter.

Worthman, C.M. & Melby, M. 2002. Toward a comparative developmental ecology of human sleep. In: Adolescent Sleep Patterns: Biological, Social, and Psychological Influences, M.A. Carskadon, ed. New York: Cambridge University Press, pp. 69-117.

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