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New Research on Cortisol, Crying, Infant Brain Development and The Morality of Babies

A crying newbornOver the past couple of weeks I’ve read two interesting articles that stuck with me. The first, Leaving baby to cry could damage brain development, parenting guru claims is from The Guardian. This article describes the difference between the two heads of the attachment vs. routine-based parenting in the UK, Penelope Leach and Gina Ford. Leach claims that scientific research shows elevated cortisol levels in babies who are left alone to cry repeatedly, and these elevated cortisol levels are toxic to a newborn’s developing brain. Ford is a proponent of the controlled crying method of “training” babies to sleep independently.

The other article is this one, The Moral Life of Babies, from the New York Times. Here, researchers describe experiments they have done with babies and young toddlers to examine what kind of moral sense babies have. Do babies understand the difference between acting “nice” and “mean”? Which do they prefer? Do babies really come into the world as a blank slate, requiring parents and caregivers to painstakingly train a sense of right and wrong through careful discipline? They found that even young babies have certain expectations about consistency and predictability in the world, and by one year of age babies can differentiate between helping and hindering behaviour, and prefer helpers to hinderers.

While the psychologist in me loves reading about the neurology of the newborn brain and the experimental minutae of morality experiments, these articles simultaneously piqued my interest and seemed rather self-evident. Can you imagine headlines screaming, “Babies are Human Beings Who Prefer When Other Humans Are Kind to Them!” Seriously: this is breaking news?

And yet, this is what I love about science, and psychology/neurology especially. Using science to prove what you know intuitively, or to discover the intricate details of exactly how that particular preference/relationship/reflex works. Millions of women intuitively know that breastfeeding is good for their babies, and now we have scientific research that shows many of the benefits of breastfeeding. Millions of parents can’t bear the sound of their baby’s cry, and now we know that repeated, prolonged crying raises a baby’s cortisol levels and can result in a child with an overactive adrenal system.

According to the Ask Dr. Sears website, Science Says: Excessive Crying Could Be Harmful to Babies, increased cortisol levels inhibit brain development, change functional areas of the brain, destroy nerve connections and result in, “increased aggression, impulsivity, and violence later in life because the brainstem floods the body with adrenaline and other stress hormones at inappropriate and frequent times,”

I would like to know more about how this relates to the kind of crying that goes on in the ordinary course of sleep training that an average family might experience. It is easy to see how cases of extreme child abuse, in which a parent or caregiver is absent or unresponsive for much of the day, for weeks or months on end, could result in brain-damagingly high cortisol levels. But what about a baby who cries for 45 minutes or an hour, for three or four nights in a row and then goes off to sleep peacefully on his own from then on, as many of the sleep training experts claim? What about a baby who cries alone for 20 minutes before every single nap or bedtime, for a year or two? What about a baby who suffers from colic and screams for hours, whether or not she is in a parent’s arms? These questions are not intended to lump anyone into the “child abuser” category, I’m just wondering out loud how these various scenarios in which we might find a distressed baby crying repeatedly might result in different neurological effects.

However, my favourite quote from the Ask Dr. Sears website is this one:

Infant developmental specialist Dr. Michael Lewis presented research findings at an American Academy of Pediatrics meeting, concluding that “the single most important influence of a child’s intellectual development is the responsiveness of the mother to the cues of her baby.”

It is reassuring to know that the work we do as parents, all the hours spent cuddling a toddler to sleep, breastfeeding on demand, reassuring a child who is afraid of the dark or carrying a teething baby who doesn’t want to be put down, all that difficult, often thankless and seemingly endless work is actually the single most important influence of a child’s intellectual development.

You can go on and chuck out those Baby Einstein DVDs now.

Stop the presses! It’s late-breaking news! Baby Benefits When Mom Responds!

Image credit: kennymatic on Flickr.

Comments on this entry are closed.

  • Dionna @ Code Name: Mama May 24, 2010, 6:24 pm

    I think it is information like this that gives us solid evidence against sleep training. Who wants to do anything that they *know* will harm their child’s developing brain? It just doesn’t make any sense.
    .-= Dionna @ Code Name: Mama´s last blog ..Breastfeeding and Bathrooms Do Not Mix =-.

  • Page @ Baby Dust Diaries June 1, 2010, 5:15 am

    I love this post too! It is featured in the May Gentle Discipline fair! Bling it out here: http://docs.google.com/View?id=adcp4gds9fvq_297gd5jv6dw
    .-= Page @ Baby Dust Diaries´s last blog ..May Gentle Discipline Fair =-.

  • Deb Chitwood June 1, 2010, 5:58 pm

    Great post! It’s interesting how often what feels right IS what’s right.
    .-= Deb Chitwood´s last blog ..Ideas from Montessori Schools – Albert Lea Montessori =-.

  • Kory September 2, 2011, 3:14 am

    “You can go on and chuck out those Baby Einstein DVDs now”
    It’s official. You’re awesome.

  • lynn September 23, 2011, 4:03 pm

    I can honestly say I believe every ounce of this article and what they found. My oldest daughter almost never cried and was easily consoled when she did. My youngest daughter though had reflux so bad, nothing consoled her, she screamed and cried about 20 hours of the day every day for the first year of her life, it was miserable for her and me alike. She has since been diagnosed @ FOUR YEARS OF AGE with ADHD and Oppositional Defiant Disorder. She is not autistic, but can be very violent at time and is verrrry impulsive. Dont get me wrong, she is very smart, and ahead on a lot of her development. But I truly believe her lack of self control and defiant behavior and impulsiveness is because she cried alll the time as a baby whether I held her or not.

    • michelle September 23, 2011, 7:57 pm

      Wow, that sounds so tough. Dealing with inconsolable crying is one of the hardest things to do as a parent. Even though the brain is wired to pick up a baseline early in life, it’s still forming connections and able to learn new ways of doing things throughout a person’s entire life. The brain really is an amazing thing! If you’re interested in learning more about how the brain changes later in life, check out The Brain That Changes Itself by Dr. Norman Doidge.

  • granmasue March 3, 2012, 12:37 pm

    good job michele!

  • Marie January 7, 2013, 10:04 am

    Good article. I feel the same about letting a baby cry. We did try controlled crying once and he did sleep better. But he has gone back to some of his old ways and I don’t want to let him cry anymore. It was hard enough the first time and my husband had to be there to stop me. It went against the grain so much that I was in tears when we had to let him cry.

    I have decided I am not doing that again just so that our DS will fit into my sleep cycle. So we are trying Elizabeth Pantley’s “No cry sleep solution”. Not sure if this will work, but this is better than letting him cry for 10 minutes.