It’s true – if you squeeze both of your baby’s hands they are likely to open their mouth. This response is called the Babkin Reflex – one of many primitive reflexes: We covered the palmar grasp reflex in week 24; “A Newborn’s Grasp is So Strong, It Can Hold Its Entire Body Weight Whilst Hanging from Its Arms” and the parachute reflex in week 37; “Babies Can Skydive!”. The video below, from here, shows this reflex in action.
The Babkin reflex doesn’t always just make a baby’s mouth open, they can also exhibit head flexion (nodding type movement), arm flexion (bending at the joints), head rotation, or any combination of these responses. The response becomes suppressed as babies become older and mostly disappears as they reach 5 months old. However, it’s also worth noting that not all babies exhibit this reflex, as noted in this study, and its absence during the newborn period is not necessarily an abnormal finding.
The relationship between our hands and mouth is evident throughout our life; babies use their hands to knead the breast when feeding, children mimic the movement of their handwriting with their tongues, have you ever found your tongue between your teeth as you thread a needle? Does your jaw tighten when you clench your fists? … You can stop trying now!
Don’t be tempted to use this technique to turn your newborn bundle of joy into a human Pez dispenser, you will not receive any little sugar pills!