Hearing a baby cry can trigger a range of responses in adults, such as sympathy, anxiety and a strong urge to help. However, new research suggests that a deeper physical reaction is also occurring. A baby’s cry, particularly if it is in pain or distress, makes our faces physically warmer.
Since they can’t speak yet, babies cry to communicate their needs, whether they’re in pain or want some attention. When a baby is in distress, they forcefully contract their ribcage, which produces high-pressure air that causes their vocal cords to vibrate chaotically. This produces complex disharmonious sounds known as nonlinear phenomena (NLP).
To study how adults respond to crying babies, scientists played 23 different recordings to 41 men and women with little to no experience with young infants. At the same time, a thermal infrared imaging camera measured subtle changes to their facial temperatures. A rise in temperature in this part of the body is governed by the autonomic nervous system, a network of nerves that controls unconscious processes such as breathing and digestion. After each cry, the participants rated whether the baby was in discomfort or in pain.