The physical development a foetus goes through is truly impressive! In only nine months they grow from a single cell into an amazing human baby. And during that time, they also learn a variety of things that they will use in the world outside the womb, without knowing what the purpose is while they are learning it.
You might remember from an earlier article that before birth, babies can learn to discriminate their mother’s voice from others. During the third trimester of pregnancy, they have become so familiar with their mother’s voice that they recognise it clearly and actually respond to it! At around the 25th week, researchers have found that a foetus’ heart rate increases when they hear their mother talking, compared to when they hear a stranger’s voice. This increase in heart rate happens because the infant becomes more alert when they hear their mother’s voice.
But learning before birth goes way beyond that. Before they are born babies show a similar increase in heart rate to hearing their father read a story. This is particularly interesting because, unlike their mother’s voice, which is likely to be relatively loud and clear, as it is a lot closer and resonates to the foetus via the mother’s body, other voices are more muffled due to the layers of protection between the baby and the outside world. But even then, they still learn to pick out their father’s voice well before they are born.
Another, perhaps even more surprising, thing is that babies can already discriminate flavours before they are born, and this continues to influence their taste afterwards. Research has found that if a baby’s mother had been drinking a glass of carrot juice four days a week for three weeks during the last trimester of pregnancy their infants liked the taste of carrot more around the time they started eating solid foods. Very recently, other researchers looked at babies’ facial expressions in the womb when their mothers ate kale versus carrots. Using a 3D scan, they could see that the faces of the babies whose mothers ate kale looked more ‘cry-like’, whereas mothers who had eaten carrots showed more of a ‘laughter-face’. Although those facial expressions resemble expressions of children and adults when they taste something they like and dislike, we do not know whether it means the same thing before birth. So, despite the ‘cry-like’ features, do not feel discouraged to let your infant explore the taste of kale, it might be just muscle movements that react to the new and bitter flavour, and they might actually like it!
So, the time a baby spends in the womb turns out to be about much more than just a time for physical growth and development. Many psychological processes, from social foundations to the development of taste, get started before a baby is even born and will help them to find their way in the outside world.