Friday, September 14, 2012

Disequilibrium at the Half-Year

   As Q-ball very quickly approaches 18 months of life, I am reminded of what I consider to be yet another fascinating observation by Gesell. 
    By observing over 10,000 infants and children, Gesell concluded that all children go through predictable stages of development, but the timing (starting points and length) are specific to each child.  The stages are composed of periods of equilibrium  and disequilibrium.  As you may imagine, the periods of disequilibrium can be tough on the child. Rapid growth and development can lead to issues with eating, sleeping, and behavior.  Consequently, these times can also be rough on parents.  And guess what Gesell's first period of disequilibrium is?  18 months!  
     As you can see in the diagram below, Gesell's stages of development progress in a spiral pattern- the periods of disequilibrium happening around the half-year and the periods of equilibrium occurring at the year mark.    
Photo credit:
    So, what behaviors can I expect around this time period?
  • Difficult, impatient (occasionally)
  • Frustrated when she can’'t communicate, cries or tantrums when not understood (I can see the frustration, but luckily we don't have too many tantrums.)
  • Can'’t make body do what she wants (I really haven't observed this.)
  • Can'’t do what she is asked, if she doesn't ’want to do it (Hmm....this is an interesting idea. I've always thought of reluctance to do something you don't want to do as a choice. I certainly see that she is starting to exert her opinions about what we do and don't do.)
  If your child is hitting a "half-year" and you've noticed some out of character behaviors, don't despair!  He'll will swing back to equilibrium in no time!

Halverson, L.& Guddemi, M. (2008). Stages of development: Ages 2 to 7.  Retrieved from
Understanding your child: A development point of view. (n.d.) The Gesell Institute. Retrieved from


  1. Amy_YouShallGoOutWithJoySeptember 14, 2012 at 4:47 PM

    Interesting. I was just reading something similar on the Ask Moxie archives the other day. I didn't notice anything out of the ordinary with Gus until about 20 months, but I blamed the 6 straight weeks of travel and other disruptions to our schedule. Now he is 22 months, and has not been sleeping properly for about 3-4 weeks--which I have seen called an 18 month sleep regression (occurring anytime between 18 and 24 months, apparently). At least, I am certainly hoping that the refusal to take naps every other day is a phase and not an indication of things to come!

  2. Ah! refusal to take a nap is very frustrating (we may have just had a similar episode here where I got a little more frustrated than I would have liked...) I certainly believe in disequilibrium, growth spurts, etc., but, as you mention, with travel and other life events, I do always wonder how they conduct these studies without outside influences.

  3. As mama to an often unsettled 2.5 year old, I'm very comforted by this information. I always learn something from your Friday posts!


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