A comprehensive review underscores that babies’ facial and bodily expressions are vital in shaping social bonds, regulating emotions, and fostering early communication, challenging traditional views of infant reactions as passive responses.
Babies are not simply reacting to the world around them when they smile, cry or look away. A new review led by Milica Nikolic at the University of Amsterdam argues that emotional expression is an active part of development, helping infants connect with caregivers, shape social exchanges and regulate their own bodies as they grow. The review, which brought together 19 papers across psychology, neuroscience, biology and philosophy, treats expression as far more than a face showing happiness or distress. It includes posture, gaze, gesture, voice, blushing and tears, all of which can carry meaning in early life.
Research on infant development supports that view. The National Library of Medicine says babies show basic emotions such as anger, joy and fear from birth through facial expression, while infant social smiling emerges in response to parental interaction in the first weeks of life. Other work summarised in the review suggests that by around two to three months, babies begin using social expression more actively in face-to-face exchanges, rather than merely responding passively to others. In other words, a smile can be an invitation as much as a reflection of feeling.
The review also points to a two-way link between brain and body. Neuroscience studies indicate that producing an emotional expression is not simply the reverse of recognising one. The same brain systems may be involved, but not in identical ways, and injury to certain areas can disrupt the emotional tone of speech even when understanding remains intact. The authors also note that outward expression does not always match inner experience, because social rules, context, goals and self-control can all change what people show. In infants, this becomes especially visible in studies of heart-rate patterns linked with calming systems in the body: these patterns rise most clearly when baby and caregiver are emotionally engaged together, not when only one side is positive.
That social back-and-forth matters because emotional learning begins early. The review says self-conscious emotions such as shame, guilt and pride emerge in the first years of life, when children are starting to understand how they appear to other people. Other research has found that even 18-month-olds can use emotional cues aimed at someone else to guide their own behaviour. For parents and caregivers, the message is practical: responding to a baby’s signals, mirroring them and joining in warm interaction can help build attachment, emotional regulation and later social understanding. Expression, the review argues, is not just evidence of an inner state. It is part of how infants learn to live with other people.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
