Don’t throw the baby out with the cortisol

Photo by Flickr user queguenae. Click for sourceI have a bullshit switch. It gets triggered when I hear certain phrases. ‘Neuroplasticity’ is one, ‘hemisphere’ is another and ‘raises dopamine’ is a regular button pusher. That’s not to say people can’t use these phrases while talking perfect sense, but I find it useful that they put me on my guard.

Most recently, I’ve found the phrase ‘raises cortisol’ to be a useful way of alerting me to the fact that the subsequent words may be a few data points short of a bar graph – potentially some poorly understood drivel.

This has been recently by demonstrated by scaremongering advice handed out to parents based on the claim that some vaguely specified study has ‘shown’ that something or other ‘raises cortisol levels’ in children.

The experts then go on to explain that cortisol is ‘bad’ for the developing brain because, as we all know, at least according to the scientific stereotype, cortisol is the ‘stress hormone’.

A few weeks ago psychologist Penelope Leach claimed that leaving babies to cry means “huge quantities of the stress hormone cortisol are being released in that baby’s brain, flooding his brain and his central nervous system, and one of the things we’ve learnt is that lots of cortisol washing about is really not good for the developing brain”.

This claim is apparently also in her new book and it made headlines around the world: ‘Crying babies at risk of brain damage’, ‘Leaving your baby to cry could damage its brain new book claims’, ‘Letting newborns cry is bad for them: study’ and so on.

The excellent Neuroskeptic blog noticed that ubiquitous psychologist Oliver James was recently advising people that leaving children in childcare could raise the risk of behaviour problems later in life because a study found that cortisol “levels had doubled within an hour of the mother leaving them in daycare”.

These claims both reflect one-dimensional thinking about how the brain works. Yes, stress tends to raise cortisol levels and there is good evidence to suggest that chronically high levels of stress and cortisol may be detrimental to brain, but this conclusion is typically drawn from people who have been through some fairly serious shit, wars, deprivation, trauma, or have specific hormone problems.

There is remarkably little research on cortisol, everyday stresses in young children and none to suggest normal variation damages the brain in any way. In fact, a couple of studies suggest that higher cortisol levels in young children are related to better mental performance but you probably won’t hear about these. You’ll also not hear about the recent study in the Journal of Pediatrics that found that breast-fed infants had higher cortisol levels.

That’s not to say that all of the studies have found a positive effect (there’s a fair research base on how higher cortisol levels during pregnancy can, in some situations, lead to later problems) but just that its common that ‘experts’ in vaguely related field will cherry pick brain studies to support what they already say.

This is particularly effective when it chimes with our folk neuroscience: dopamine equals addiction, cortisol equals stress, serotonin equals enjoyment, the right-hemisphere equals creativity and so on. None of which makes sense its own. They’re all useless when used as stereotypes.

As Neuroskeptic notes, virtually every form of physical activity raises cortisol levels, so you can’t just blithely apply the over-generalisation without making a nonsense of the world.

Or indeed, of childcare.

Link to Neuroskeptic on cortisol and pop childcare advice.

6 Comments

  1. Posted May 12, 2010 at 3:49 am | Permalink

    Sometimes the baby has to cry. Yes it is horrible but if you get up every time the binky drops out of their mouth they will have you up 7 times a night for the next 7 years. Better to just rip that bandaid off and let them cry it out.

  2. woly
    Posted May 12, 2010 at 7:35 am | Permalink

    Just out of curiosity, I was wondering if you could link me to some neuroplasticity research that sets off your bullshit switch? :)

  3. bowser
    Posted May 12, 2010 at 9:27 pm | Permalink

    Before my second child was born (me and my wife’s daughter), I thought that I knew enough about babies and what it takes to do a good job of raising a kid. My son was 8 when she was born and he’s a good kid; bright, thoughtful, kind, considerate, etc. So, I thought that babies are babies; just little eating, sleeping, pooping, peeing machines… boy, was I ever wrong.
    Right from day one my daughter had (and has) a much different personality than my son did even as a newborn. As time has gone on those differences have become even more clear, not only in terms of personality but with cognitive development, social cognition, etc. as well.
    With our son we devoutly followed the attachment parenting regimen. It worked well for us, and to my mind well for our son too. However, our daughter was such that we couldn’t do everything the attachment way… sometimes she goes into meltdown mode and absolutely will not let either of us touch her during that time… we’d love to be able to hold her, comfort her, help her feel better, etc. but she’s not that way… sometimes she just needs to cry it out. That has been difficult for me personally, it’s anathema to what you’re supposed to do when you use attachment methods. But, it’s her decision, not ours, and that’s why I think it’s okay. It’s not a situation we are forcing on her. Even at 20 mos. now, we’re letting her make those decisions.
    And she’s in day-care 3 days a week. Cortisol causing brain damage? Theoretically, sure. Practically? This seems to be another case of applying conclusions from study on one topic to another topic that they don’t really apply to. Sad, but it’s a fact of life in academics; I see it all the time. Just look at the recent work of people like Chomsky, Lakoff, and Dawkins the past few years.

  4. Posted May 13, 2010 at 12:38 am | Permalink

    Isn’t there another take on this cortisol and babies thing. Some things I have read (i’m not a scientist) indicate that corisol blocks some of the ability to learn. By that logic, when the aby cries, the cortisol flies, and the baby doesn’t “remember” a thing about it. Could even get toughened up by it.

  5. Ryan
    Posted May 14, 2010 at 7:02 pm | Permalink

    Now obviously a lot of this is BS, but still I wouldn’t be so quick to assume there’s a huge difference between say, the stress of being at war and the stresses of childhood. After years of knowing nothing but your parents’ love and having them as your only comfort, being left in a new environment where they are suddenly gone, you have no idea if they’re ever coming back, and you’re surrounded by things you don’t understand and people you can’t communicate with could very well be a traumatic experience.
    I’m not arguing against daycare because hey sometimes its what you’ve got to do. But it doesn’t seem totally ridiculous that if done incorrectly, it could induce stress significant enough to cause long-term effects.
    Similarly, I couldn’t really see myself being someone who just lets a child cry it out. Maybe I’ll feel differently if I get “one of those kids” but I know a lot of families that get by just fine without ever having to leave their child screaming in the dark for hours on end. And our 2 year old son sleeps through the night no problem without ever having had to cry himself to sleep. From the baby’s perspective it really seems like it would be an overwhelmingly terrifying experience.

  6. Posted April 3, 2013 at 5:39 pm | Permalink

    I don’t think we need to talk in extremes. I believe that the essential point here is that when babies cry, it is the way they are attempting to tell us something is not right with them. If we haven’t seen other earlier cues or their needs haven’t been met, they then cry to alert us.
    As parents, we automatically respond to a crying baby… or we should. It’s built into us.
    Once we begin to shut that down and not respond, then we are blocking off a vital part of ourselves which needs to be functioning in order to take care of our distressed infant.
    Infants are not crying to manipulate. They have needs and if those needs are not met, they cry. Many cultures around the world are shocked and dismayed to hear that in North America, babies cry. It is not the norm!
    If babies needs were being met (skin to skin, holding, calming, in someone’s arms, nursed) they would have less need to cry as a last ditch effort to have someone pay attention to them.
    Studies show that babies left along to cry it out, begin by making very loud cries to draw attention, then the cries diminish slowly, becoming whimpers and finally they do stop. Not because they are fine, but because they move into a state of apathy – the message they receive is no one cares about my distress, so they give up. It’s simple.
    How is it that we can’t see this? How is it that our instinctive parenting is not functioning? How is it that we are a society that believes that babies can be spoiled if we hold them often and respond to their distress immediately?
    We are not creating independent children and adults by refusing them love and nurturing. Instead they will be clingy and insecure. The research supports this. The information is out there. But aside from looking at research… simply look at your distressed infant. We are made to respond to cries. Block that out and you run the risk of becoming insensitive and your baby suffers as a result.
    Oh, and this one is also a myth – babies cry to exercise their lungs….. tell that to the crying 7 week old… or 7 day old…


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