For parents around the world, the scope of parenting practices and advice has long been a source of much debate and differing opinions, especially regarding "sleep training." In a joint opinion piece by Professor Darcia Narvaez, a psychology professor at the University of Notre Dame, and Catriona K tannion, an assistant professor at the University of Southern Denmark, published on the British iNews website, the subject of "sleep training" remains one of the most divisive issues. This relates to whether leaving children alone to cry themselves to sleep is beneficial to the extent claimed by proponents of this method or not.
It has been acknowledged that children tend to become distressed easily and struggle to sleep through the night. However, these days, many parents adopt a different approach, with little or no intervention if their child wakes and begins to cry.
### Encouraging Self-Soothing
Some researchers, bloggers, and doctors advocate for "sleep training," claiming it helps children learn to self-soothe. The researchers state, "But as researchers into the biological and psychological needs of infants for the past fifteen years, we can confidently say that this is simply a myth because sleep training actually undermines what early childhood experts call the need for secure, stable relationships and care, in addition to violating parental instincts to soothe their little ones."
### Heritage of Mammals
From an evolutionary perspective, sleep training conflicts with the mammalian heritage of humans, which emphasizes caring companionship from responsive caregivers who provide ample affection and a comforting presence. As social mammals, children require tender touch and calming care as they learn self-regulation and how to live outside the womb. If caregivers do not physically embrace and be present with their infants for several hours a day, multiple systems can become maladaptive, as stress responses can become overstimulated, meaning the brain is always on the lookout for threats, even when such threats do not actually exist (for instance, when someone accidentally bumps into you but you perceive it as a deliberate provocation).
A significant part of the problem with trying to train a child to sleep is that it undermines key aspects of child development, such as brain functions, social and emotional intelligence, and self-confidence with oneself, others, and the world.
### Isolated Monkey Infants
Experiments conducted with isolated monkey infants have proven that denying them maternal touch (even though they can still smell, hear, and see other monkeys) leads to various brain issues and social distortions. Humans belong to social mammals and need responsive and nurturing care, at the very least. Human infants are particularly immature at full term (40-42 weeks), with only 25% of an adult's brain size in place because, as humans evolved to walk upright, the female pelvis became narrower.
### From 1.5 to 3 Years
Due to the narrow female pelvis, infants appear fetal-like compared to other animals until around 18 months old, when the upper skull bones finally fuse. The human infant's brain triples in size by the age of three, and during the early months and years, the child's brain and body establish multiple systems and respond to the care they receive. Stress responses can become hyperactive if children are not kept content most of the time — leading to potential long-term physical and mental health issues.
### Continuous Biobehavioral Synchronization
Continuous biobehavioral synchronization with parents (i.e., the condition of physical presence coupled with heart rhythms, autonomic function, brain wave coordination, and coordination of hormone secretion such as oxytocin) is crucial in a child's life, laying the foundation for self-regulation and social and emotional intelligence in the future. Because this "cry-it-out" sleep training can be harmful to a rapidly developing brain and psyche, researchers have documented how sleep training can activate fight-or-flight instincts and irritability in infants in the face of severe distress due to being deprived of comforting physical touch.
### Lack of Social Trust
When the distress of separation and unresponsiveness persists for long periods, the infant may calm, but they retain limited energy. This withdrawal can manifest as a lack of social trust, which can carry into adulthood. These patterns can persist into adulthood when extreme situations lead to a closure in thinking and feeling when individuals are triggered by panic or anger.
### Foundation for Healthy Development
Children's brains and bodies are deeply shaped by caregiving practices, and this shaping continues throughout life unless treated or intervened upon. In other words, parents have a significant impact on their children's character and social-emotional intelligence. When parents feel calm and at ease, it facilitates healthy development in children.
### Genuine Care
Genuine care and responsiveness mean the ability to adapt to what children need, helping them stay calm, attending to gestures and facial expressions indicating discomfort, and moving gently to restore balance. Importantly, a child's cry is a late signal of need, so ignoring all signals and signs until reaching the point of crying means that parents may have waited far too long before addressing their infant's needs.
