Sep 17, 2025 07:00:00

A baby's cry physically 'makes adults' faces heat up' - study finds

You may have heard people say, 'When you're raising a child, you start to understand the meaning of a baby's cry.' New research has found that a baby's cry when it's in pain can physically heat up an adult's face.

Nonlinear acoustic phenomena tune the adults' facial thermal response to baby cries with the cry amplitude envelope | Journal of The Royal Society Interface

https://royalsocietypublishing.org/doi/10.1098/rsif.2025.0150

The Sound of a Baby Crying Can Make Adults Physically Hotter : ScienceAlert
https://www.sciencealert.com/the-sound-of-a-baby-crying-can-make-adults-physically-hotter

When you hear a baby crying, even if it's not your own baby, you may wonder if they're okay and feel anxious about whether their parents can handle the situation appropriately. For babies who can't express themselves verbally, crying is an important way to get the support they need from their caregivers, so crying can be unbearable to listen to.

Of particular importance is the cry that babies make when they experience pain that could be life-threatening or injury-related. It has been found that babies who are in actual pain cry in a different voice than babies who are experiencing mild discomfort.

A baby's pain cry differs from other voices in the way it's produced: by contracting the rib cage and forcing high-pressure air through the vocal cords, it produces a range of pitches and dissonances that acousticians call ' nonlinear phenomena.' 'NLP has been established as a reliable indicator of the level of distress and pain expressed by babies,' says bioacoustician Renee Rego of Jean Monnet University in France and her team.

It is generally known that caregivers can distinguish between cries of simple discomfort and cries that indicate a more pressing problem, such as pain, but the mechanisms by which people's bodies respond to and distinguish between these types of cries are less well understood.

To investigate the physiological effects of crying babies on the adult nervous system, the researchers conducted a study on 41 participants, 21 men and 20 women, with an average age of 35.

The subjects listened to two sounds: a baby crying during a bath due to mild discomfort, and a baby crying during a vaccination. A thermographic camera tracked changes in facial temperature. Facial temperature rise is controlled by the autonomic

nervous system, a largely unconscious part of the nervous system that regulates functions like heart rate, breathing, and digestion.

The results of the experiment showed that when subjects heard crying sounds with higher levels of NLP, their facial temperature rose more dramatically. This suggests that crying sounds containing NLP are more effective at attracting adults' attention at a physiological level than crying sounds with little or no NLP. The response to crying sounds containing NLP was observed equally in male and female subjects.

The research team stated, 'Changes in listeners' facial temperature are an indicator of autonomic emotional responses and reflect the pain expressed in the baby's cry.' 'Our results indicate that NLP levels in the cry dynamically modulate listeners' facial thermal responses, regardless of gender.'

The participants in this study had little or no experience caring for babies, so the results do not reflect the physiological responses of parents to the sound of a crying baby. Future research may reveal how physiological responses to NLP vary depending on parenting experience.