Head-Banging and Rocking in Babies

   At almost exactly 9-months, Q-ball started head-bopping, bouncing, and plain just rocking out by herself.  She was clearly creating some pretty awesome tunes in her head.  Sometimes she'd start when she was supporting herself on a chair; sometimes while she was sitting, using her wooden spoon as a drumstick; and sometimes mid-crawl she'd just start rocking back and forth, like a Olympic sprinter in his box before a race.  She always started to display some head rocking activity before nap or bedtime- while we were rocking in our chair, she would gently exaggerate the movement.  So, what's going on?

Credit: Schlinger, H

   First of all, these "rhythmical stereotypies" as famed infant development researcher Esther Thelen (I've discussed her work previously here) termed them, are totally normal for infants under 1 year.  While researching the topic, it seemed that many nervous parents look into what they fear are abnormal behaviors.  But, have no fear!  These movements are actually are of your baby's neuromuscular maturation (i.e. your brain being able to control muscle movement vs. movement by reflex.)  In fact, as I will explain, some studies have show that the more rhythmical stereotypies (especially head banging and head rolling) a baby displays, the better. 

   Thelen actually identified 47 different movement patterns as rhythmical stereotypies, grouping them into four different categories- leg and feet movements, torso movements, arms, hands, and finger movements, and head and face movements.  The most common movements are kicking, rubbing feet against the floor, waving arms, and banging hands against the floor.  Head banging and head rolling (which seem to be most worrisome to parents) are also forms of rhythmical stereotypies.  Hand gazing is yet another example- one that Q-ball commonly also practices.  These movements typically start at about 3 months (the time when reflexes start to decline) and peak at around nine months (which is now for Q-ball!) 

     Because nearly all healthy babies exhibit these movements, most researchers agree they occur innately in humans.  But, the environment also appears to play a role.  When I read this, I realized that this was true in Q-ball's case.  I first noticed her hand gazing practice while I was breastfeeding her when she was about 4 months old.  Even now, she is most likely to make this movement when she is breastfeeding or when she is in her highchair.  Similarly, the gentle head rocking I mentioned in the beginning of this post appears to be related to sleepy times. 

       It is true that rhythmical movements like the ones babies display can also be a symptom of mental retardation or other mental illness.  However, research has found no links in rhythmical movements in the first year and later mental illness.  In fact, one research found that higher levels of rhythmical movements in the first year is related to higher levels of later cognitive performance in boys (sorry, girls, not true for you, although this may simply be because boys are more active than girls, even as infants.)  Additionally, these researchers found that rhythmical movements at 13 months for both boys and girls in social settings can be a way to communicate (like when babies rock towards a toy or banging a stick on the ground) and may again indicate higher cognitive skills. 

     So, enjoy watching your infants head bang, bang spoons, and dance!  It certainly means that they are learning to control all of their different muscles and may mean they will be smarter later!

Sources:

Kroeker, R., Unis, A., & Scakett, G.P. (2002). Characteristics of early rhythmic behaviors in
children at risk for developmental disorders. Journal of American academy of child and adolescent psychiatry, 41(1), 67-74.

Schlinger, H. (1995). A behavior analytic view of child development. Plenum Press: NY.

Thelen E. (1979). Rhythmical stereotypies in normal human infants. Animal behavior, 27(3), 699-715.