Interpreting the data
There have long been signs that newborn smiles could signal positive emotions to some extent. Smiles have been noted in the first few days of life as a response to stroking of the cheek or the belly. Newborns also smile in response to sweet tastes and smells. These findings were published decades ago when smiles were considered purely as innate reflexes. The reason that scientists at the time didn’t interpret them as emotional was partly because the smiles looked different to social smiles.
“Real” smiles – called Duchenne smiles – involve not only the major muscle that pulls the mouth to the side and upward, but also the muscles around the eyes. Neonatal smiles were thought to involve only the mouth region. However, when scientists micro-analysed facial movements, frame by frame, using a dedicated coding system, smiles from as early as one day of age were more often than not accompanied by cheek and eye movements.
More and more studies have since suggested that newborn babies do smile when they are awake, and that these smiles closely resemble real social smiles. And when newborns are in an interactive, awake state, they smile twice as much as compared to when they are asleep – more evidence that social factors could be involved. What’s more, babies often start with moving their cheeks and their brows before they smile, as if focusing their attention on the caregiver’s face. So it is completely possible that these newborn babies actually mean to smile.
Babies learn about the power of smiling early. While caregivers often smile at their newborns, this behaviour will be dependent on the baby’s state – they are less likely to smile if the baby is crying. As a result, babies quickly gain a remarkable ability to regulate the behaviour of their parents. If a baby keeps eye contact, blinks and smiles, their parent will likely smile back – making the smile rewarding.
Unsurprisingly, studies on mothers have shown that they are deeply affected by the smiles of their babies – even on a neurophysiological level. One study measured brain activity in mothers using fMRI scanning. When mothers saw their own infant smiling, activities in areas of the brain involved in processing emotions – including the amygdala and the limbic system – were enhanced. Dopaminergic brain areas, known as the reward system in the brain, were also highly active.
Unfortunately, behavioural studies with neonates are still scarce and require elaborate analyses to interpret the meanings of certain behaviour. While further studies are needed, it is plausible to assume that these early smiles have a social meaning. To many of us in the field, it is at the very least clear that these smiles are definitely more than just a reflex.