Research shows prolonged crying lowers IQ in babies

Here’s a fascinating research project coming out of Norway, in cooperation with the National Institutes of Health, focused on the cognitive consequences of prolonged crying in young babies. As you’ll see, the conclusions very much bear out what we attachment parenting advocates have been evangelizing for years:


Research on long term cognitive development in children with prolonged crying.
BACKGROUND: Long term studies of cognitive development and colic have not differentiated between typical colic and prolonged crying.
OBJECTIVE: To evaluate whether colic and excessive crying that persists beyond 3 months is associated with adverse cognitive development.
DESIGN: Prospective cohort study. A sample of 561 women was enrolled in the second trimester of pregnancy. Colic and prolonged crying were based on crying behaviour assessed at 6 and 13 weeks. Children’s intelligence, motor abilities, and behaviour were measured at 5 years (n = 327). Known risk factors for cognitive impairment were ascertained prenatally, after birth, at 6 and 13 weeks, at 6, 9, and 13 months, and at 5 years of age.


RESULTS: Children with prolonged crying (but not those with colic only) had an adjusted mean IQ that was 9 points lower than the control group. Their performance and verbal IQ scores were 9.2 and 6.7 points lower than the control group, respectively. The prolonged crying group also had significantly poorer fine motor abilities compared with the control group. Colic had no effect on cognitive development.
CONCLUSIONS: Excessive, uncontrolled crying that persists beyond 3 months of age in infants without other signs of neurological damage may be a marker for cognitive deficits during childhood. Such infants need to be examined and followed up more intensively.


This should be pretty convincing data, with a research group of 327 babies, if you’re still unsure about whether you should let your baby “cry it out” or if you’re thinking of trying any of the progressive desensitization sleeping methods promoted by various so-called experts.
I’d also like to take this opportunity to point out that a family bed — or at least a crib in the same room as the parents — further minimizes excessive crying too, with the positive long-term outcome indicated by this research.
If I may say so, it’s nice to find that research bears out what we attachment parents have been preaching for years…

18 comments on “Research shows prolonged crying lowers IQ in babies

  1. Thanks for posting this study! There’s a good reason why, when a child cries, the parent feels a strong instinctual urge to pick up and comfort the child. We always would get up and comfort our children whenever they needed it, and now that they’re middle-school aged, they’re very well adjusted and self confident. Lesson for new parents: now that my children are older, as a parent, I miss those early experiences, including comforting them to sleep.

  2. No one wants to let babies cry, but I don’t think this research necessarily supports your position.
    I see a few problems with your assumptions. After looking at the link, I didn’t see any reference to this prolonged crying being the “crying it out” type of crying to which you are referring. It is also hard to know if the children who tended to cry more had another similarity that might have influenced their IQs. The relationship does not seem to be a causal relationship at all but correlational. Furthermore assuming that IQ is static is somewhat problematic. Many factors influence IQ and IQ can vary over time.

    • @beth.. no beth, IQ is almost entirely genetic and extremely static. It might vary as a young person’s brain develops, but that is the extent of it.

  3. Your title and statement is misleading and completely at odds with the research presented. The research is for children who “cry excessively beyond three months of age” not children who “cry it out” or cry for prolonged periods of time, as you say. In other words, it is the age at which the child cries, not the length of individual crying episodes that the research is based upon.
    Also, the research article’s conclusion states that excessive, uncontrolled crying beyond three months of age “…may be a marker for cognitive deficits during childhood.” A “marker” is an “indicator” of a problem that already exists. Your title, however says “prolonged crying lowers iq in babies.” That’s a pretty big leap!
    I don’t know who your readers are, but I hope they read more critically than you seem to do.

  4. With due respect, I must agree with the posters who call you to task about assuming this study refers to sleep training via controlled crying. It patently does not.
    The study clearly refers to “prolonged crying after three months” and “excessive, uncontrolled crying.” This is far different from the (relatively) short, specific times that parents *allow* crying to occur during sleep training.
    Excessive and uncontrolled crying refers to the baby who cries *despite all attempts to soothe*, who tests every frayed parental nerve and still won’t stop. “Cry it out” (which I’m no cheerleader for) involves controlled periods of time when the child cries, and only at bedtimes. And it shouldn’t last long.
    And there’s nothing in the study that says crying *causes* lower IQ. It’s simply a symptom of an already-present neurological problem.

  5. I appreciate those people who have come here and considered the research. While I am making a leap from correlational data to discuss causality, I think I could make the same statement from a different direction and have something that’s just as true: The correlation researchers have found between excessive crying and a drop in IQ strongly suggests that there’s an additional value to attachment parenting inasmuch as it helps minimize periods of extended crying.
    But even without that, man, it gives me the shivers to hear “sleep training” coming out of the mouths of otherwise rational adults. The reason that children crying during bed time doesn’t last long is because you desensitize them and convince them that their fears and need for other people are something they have to deal with internally, to “get over it”, and they give up.
    Try this experiment some time: let a young child cry until they’re exhausted (I’ve seen children do this, I would never do it with my own children) and you’ll see that they fall into a zombie-like stupor, completely unplugged and not present at all. Perhaps that can help lead them to sleep, but it’s not a path I choose for my children, nor do I expect that it’s a great message for them to receive as wee ones either.

  6. While I understand your desire to support your style of parenting, I sincerely believe you must have not read the study which you are touting in support of your ideas. No matter how you try to rephrase your statement, you cannot use this article to promote a parenting style or show causality. (indeed your rephrasing still implies causality). Prolonged crying is also assumed on your part to be because the infant is left to deal with it on its own. Anyone who has experienced a child with prolonged crying knows that one can feed, bounce, swing, pace, and weep right along while the child still continues to cry. Prolonged crying is the state of colic that continues more than the first three months, not a result of parenting style.
    When people like you try to twist science and its results to suit their own desires, and support their own ideas instead of presenting the actual facts, you do a disservice to science and the truth.

  7. In our experience, over 90% of all colic is the result of some sort digestive upset. This can be either gassiness that infants newborn digestive system is unable to process, or acid reflux, also caused by inability of infants immature digestion to process food efficiently. In some rare cases, colic sysmptoms may manifest due to seperation anxiety, over-stimulation or other external environmental factors. I doubt the causality or connection between colic and IQ. If there is excessive crying that is related to a brain disfunction, then I would not agree that is colic.

  8. Dave:
    Your twisted logic is beyond words. First you take scientific research and jump across the Grand Canyon and then you suggest:
    “I think I could make the same statement from a different direction and have something that’s just as true: The correlation researchers have found between excessive crying and a drop in IQ strongly suggests that there’s an additional value to attachment parenting inasmuch as it helps minimize periods of extended crying.”
    This is a different (conveniently more vague) whacked out rationalization of the same statement. You just jumped from LA to Tokyo using a less substantive explanation!
    Babies cry for attention. Period. It’s that simple. Ever watch Super Nanny or Nanny 911? Perhaps you or your friends have been featured. Then again, perhaps not. You’re perfectly happy not having any life whatsoever… as a parent, during you child’s infancy. Your life, hobbies, career… even your purpose is essentially forfeited and replaced with “raising my child – FOREVER!” (nothing else… nothing)
    When your child goes off to college or have his/her own life (assuming you let him/her) you then graduate to a more mature and well-documented psychosis called “helicopter parenting” (http://seattlepi.nwsource.com/lifestyle/209473_copterparents.html) wherein you are so “in love” with your child (mental umbilical still attached) that you’ve forgotten how to live a life beyond the child. What’s more, you decide to actually block your child from having purpose in his/her life. Procreation is not only the number one reason we’re here on Earth, it’s the ONLY reason we’re here. Can’t you see how extreme your condition is?
    Thankfully, attachment parents retain the know-how (and somehow the time) to eat food and drink water every day so that they can blog about their psychosis as if it’s the “better way” to parent.

  9. One of the most interesting things about running a parenting web site is that people are so darn PASSIONATE about parenting, particularly about their own approach to parenting. Jeff, I respect your perspective and support your right to have a different perspective, but until you walk a mile in my shoes, please skip the insults and gratuitous hostility. If you’re willing to be hoodwinked by “Super Nanny” and other television drivel that’s staged (do you ever get to see the households where she can’t get things to improve? Hmmm….) that’s your choice. Just don’t use that as the filter to judge what we’re doing and the choices we’re making as we raise our children.
    And for the record, we have plenty active social lives, both have hobbies we pursue, classes we take and evening events we frequent. Do you?

  10. Dave:
    I don’t think my comments are hostile and you do nothing to defend your leaps of logic in your response. How can you?
    I’ve walked in your shoes. How do you know I’ve not? Fairly presumptuous.
    Do you believe that television executives are out to do battle with the “attachment theory?” I believe they’re out to sell advertising. How? In this case, by pointing cameras at the most illogical and, yet common, human behaivors in existance. Attachment parenting being one of them… wherein parents are so concerned with how to love their kids that they refuse to offer children ANY alone time.
    So, what have I learned on your board? I’ve learned that you presume a lot, are willing to sacrifice your own critical thinking (to protect your theories) and, most disappointing of all, run a Web site that expresses your opinion and welcomes others — yet passes judgement on others’ opinions in the end and holds your beliefs as right (others are simply wrong). Why? You’re you and I’m me and I’ll never be you so I’m wrong.
    Respect my opinion, indeed. I think this blog is mostly about talking to yourself and others with like minds. I don’t find this to be the least bit productive in terms of critical thinking. Just my opinion 🙂

  11. I’d say that we’re dancing a passive aggressive dance here, Jeff, and suggest that there’s not much point in going any further in this discussion. You come onto our weblog and insult not just us, but the parenting strategy we – and thousands of other parents – have chosen, then get surprised that I don’t seem to appreciate your “insight”?
    That’s your right, I suppose.
    But I really don’t see any value in continuing the conversation any further. Good luck to you with your path and your parenting decisions. However you do it, parenting’s a tough job…

  12. Thank you for posting this page. I am doing a paper for my environmental class, and I came across your page. I think there is no better way to raise a child than to give them your utmost love and attention, which is what attachment parenting really comes down to, without even going into the details. I completely agree with your views and commend your dedication to your values and standards…I am sure you have a wonderful family, keep up the good work! Thanks again…

  13. great article! thanks for posting. i enjoy your blog very much. i also commend you on your ability to leave certain comments.
    sleep training, IMHO, is abuse. plain and simple!

  14. May the research prove it or not, but I 100% agree that excessive crying in baby is a dangerous signal and can be a symptoms of mental disorder.
    As a new mom of just 3 months old baby, I had a hard time getting my baby to stop crying. I had read many articles and blogs on “baby cryingâ€? topic and I have found that at the most (maximum) the baby cries about 3 hours in 24 hours, and if the baby cried more than this on consistent and daily basis then it can be called as a excessive crying and definitely it is a dangerous sign and alert signal for parents to give more attention toward their crying baby.

  15. Well, i have read through the column, and the comments following, and it doesn’t make alot of since to me. It talks about letting a baby cry it out lowers cognitive reasoning, but colic has no life-long effects. I’m not the smartest guy in the world, but it sounds like if i let my child cry, they will have a lower IQ, but if they develop colic(a lot worse than CIO method), they will somehow be better off. I hope no one got paid for this research.

  16. Wow, excessive crying in a baby lowers their IQ?! My first born son did not stop crying due to silent reflux for the first 4 months of his life. He was literally awake crying for up to 7 hours straight sometimes. During that time he co slept with me and I very much practiced “attachment parenting”. The only thing that stopped his crying was when he went on medication at 16 weeks old. If you were to compare him now to other children his age he would be considered “advanced”. My 2nd born was a gentle bub who co-slept with me until 4 months old when he started to settle himself to sleep. He never cried but compared to his peers would be considered as being behind in meeting his milestones. You should NEVER make assumptions, every child is different, and it is very dangerous to write articles such as this.

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