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Child development experts have long known that the connection between caregivers and children is critical. Now a limited but growing body of research is zeroing in on laughter as a window into healthy brain development and a child’s blossoming social world.

Laughter, which emerges long before babies say their first words, could have underrecognized clinical significance, experts say — particularly in an age of digital distraction and at a time when parents are under significant stress. For young children, laughter isn’t just frivolity; as a physiological response to the unexpected, it helps them process the world. Experts say it may also serve as an important developmental marker, alongside walking and talking.

“Laughter is probably one of our most important social abilities,” said Sophie Scott, PhD, a professor of cognitive neuroscience at University College London, London, England.

Laughter and the Brain

The human brain has two systems for controlling vocalization. “One is evolutionarily ancient,” Scott said — associated with spontaneous, involuntary emotional reaction. “The other is the volitional vocalization network — in the lateral parts of the brain.” In newborns, that latter network is present but immature and not yet functional. Yet infants come into the world ready to engage with other people.

In typically developing babies, involuntary laughter — a reflexive, sensory-driven response — happens at about 3-4 months. This is associated with the brain’s limbic structures, which regulate emotion, memory, and behavior, said Gina Mireault, PhD, a developmental psychologist and professor at Vermont State University, Johnson, Vermont. Around 6 months, babies begin to laugh voluntarily — a milestone associated with developing motor and speech centers of the brain.

Most laughter is social, Mireault said. Research shows people are 30 times more likely to laugh around others. Young toddlers already understand laughter “in quite complex ways,” doing things to make their parents laugh or using their parents’ laughter to assess whether situations are worrying or safe.

Laughter as a Marker of Healthy Development

For a young child, laughter is a tool that helps them process the unexpected, determining whether a surprise is scary or funny, said Mary Helen Immordino-Yang, EdD, a professor of education, psychology, and neuroscience at the University of Southern California, Los Angeles. A jack-in-the-box can trigger cries if seen as a threat — or giggles if viewed as safe and playful.

“Laughter is really a sign of letting go of stress, letting go of worry or fear,” Immordino-Yang said, “experiencing things that are surprising not as unsafe but as pleasurable.”

The back-and-forth of shared experience and the physiologic attunement that naturally unfolds between children and the adults around them fundamentally shape a child’s development. Research shows that shared laughter activates neural reward circuits and elevates oxytocin in both the infant and the adult. Studies show the more synchrony there is between the two, the higher oxytocin levels climb. By 5 or 6 months, babies are more likely to smile or laugh in response to a parent smiling or laughing, according to research by Mireault.

Laughter has other benefits. It releases dopamine and serotonin, which contribute to calmness and creativity, said child development expert Jacqueline Harding, MA, Cert Ed, a visiting research fellow at Middlesex University London, London, England, and author of The Brain That Loves to Laugh. Relaxed states can also modulate pain perception and improve patient engagement, explaining why major pediatric medical centers labor to transform spaces into playful, happy environments.

Parental Stress and Digital Distraction

Because laughter is largely social, the digital age poses a threat. “You get less laughter if you’re on the phone, and less again if you’re just on text,” Scott said. High stress and distraction can also disrupt the co-regulatory loop between parents and children, reducing opportunities for levity. In 2024, US Surgeon General Vivek Murthy declared parental stress an urgent public health issue, with 33% of parents reporting high stress in the past month compared with 20% of other adults.

While “technoference” — a parent’s technology use in a child’s presence — remains understudied, a 2025 research review in JAMA Pediatrics found that parental screen use was negatively associated with children’s cognitive and psychosocial outcomes. Data from Pew found that 56% of parents said they spent “too much time on their smartphone,” and 68% said they felt distracted by their phones when spending time with their children.

Clinical Takeaways

For pediatricians, laughter could “provide an early inroad into typical development,” Mireault said. Some parents of children with autism, for example, report not understanding their child’s laughter — a sign that laughter may be rooted in internal sensory experience rather than shared social cues. “These emotional markers are just as important as the physical ones like walking and talking,” Mireault said.

Support for young families “is essential,” Immordino-Yang said. Neural circuits are rapidly changing for new parents, too. “Our biology is deeply social, and it’s not just one-sided,” Immordino-Yang said. “It’s not just the infant that’s developing through engaging with one another — it’s the parent as well.”

Clinicians can also encourage parents to see laughter as an antidote to stress, Mireault said. “Laughter is free. It doesn’t require anything special; it just requires togetherness,” Mireault said. “Your job as a parent is to just accept the invitation.”

The experts cited in this article had no relevant disclosures.