Why Babies Laugh, with Gina Mireault, PhD | Speaking of Psychology

Why It Matters

Understanding when and why babies laugh reveals early social cognition and attachment cues, offering parents and professionals a non‑verbal metric for healthy developmental trajectories.

Key Takeaways

• Babies begin voluntary smiling around six weeks, laughter emerges at four months.
• Unexpected sounds, touches, and incongruity trigger infant giggles.
• Infants can discern humor without parental cues, laughing independently.
• By six months, babies intentionally create funny situations for caregivers.
• Early laughter patterns may predict attachment quality and social development.

Summary

The episode explores infant laughter as a developmental milestone, featuring Dr. Gina Moreau of Vermont State University. She explains that involuntary smiles appear in utero, voluntary smiling emerges around six weeks, and genuine laughter typically surfaces at four months, often in response to surprising noises, tactile stimuli, or incongruous events.

Research from Moreau’s Infant Laughter Lab shows babies can differentiate ordinary from absurd situations without parental prompting. In a “comedy club” experiment, six‑month‑olds laughed more when parents remained neutral, indicating independent humor detection. By five to six months, infants begin to imitate funny actions and intentionally disrupt expectations—knocking over towers or tearing paper—to elicit caregiver laughter, demonstrating early intentionality.

Memorable examples include a newborn’s first laugh at a sudden sneeze, a clown‑nose foam ball that sparked giggles without adult cues, and the universal appeal of peekaboo and tickling. The discussion also touches on “polite” or fake laughter emerging around six months, and notes that other mammals, especially primates, exhibit comparable laughter behaviors.

These findings suggest that infant laughter is a social signal linked to attachment formation and cognitive development. Parents can view early giggles as cues of emerging social understanding, while clinicians might consider atypical laughter patterns as early indicators for further developmental monitoring.

Original Description

Before babies have the words to tell us what they're thinking, they can laugh. Developmental psychologist Gina Mireault, PhD, explains how she sets up a “baby comedy club” in her lab; what babies find funny and why; when babies start trying to make other people laugh; and what studying laughter can tell us about babies’ cognitive development and how they experience the world in their first year of life.

__________________________________

The American Psychological Association is the leading scientific and professional organization representing psychology in the United States, with more than 157,000 researchers, educators, clinicians, consultants and students as its members.

To learn more about APA visit http://www.apa.org

Follow APA on social media:

Facebook https://www.facebook.com/AmericanPsychologicalAssociation/

Twitter https://twitter.com/apa

LinkedIn https://www.linkedin.com/company/american-psychological-association/

Instagram https://www.instagram.com/apa_org/

Threads https://www.threads.net/@apa_org