By Alex Golbin, MD
There was a period in the history of America when the use of pacifiers for small children was not fashionable. It took two generations of disturbed kids to realize that the pacifier does induce non-nutritive sucking movements, and the next generations of scientists to figure out “why”.
Non-nutritive sucking (movements of the lips as if the infant sucks the breast when it is fully fed) serves the very important physiological function of forming mature electrical activity of the brain, to assist in maintaining a stable attention or/and effective “switch” from one activity to another, say, from wakefulness to sleep or from crying to calmness.
Scientists consistently have demonstrated that non-nutritive sucking movements are universal for the animal world and for humans in every culture. Experimental studies on rabbit embryos show that sucking movements appears long before delivery and their amount directly correlated with the post delivery health of the animal.
The concrete mechanism of the positive effect of sucking is now well studied: rhythmic sucking movements elicit identical electrical rhythm in the brain. This so called “effect of synchronization” is essential for the brain, because we are born without such rhythms. Brain rhythms of calmness, alertness, attentions, etc. are developed later in life, and their development is reinforced by muscle activity of the different parts of the body. That is why sucking movements in a rabbit’s fetus after birth quickly changes into a scratching reflex – something that was used by trainers in the animal circus. If we symbolically thought that our brain is “God” and our body parts “slaves”, now we know that in some conditions the peripheral body parts teach the brain to mature.
In humans, if we do not provide a pacifier for our infants, many of them will develop bad habits, such as finger or clothes sucking, hair pulling etc. This is a message for a mom-to-be: be sure that your child has as many non-nutritive sucking movements as he or she needs if you want your child and you to have a chance to sleep at night.