A new study published in PLOS ONE confirms that yawns are contagious even before birth, challenging earlier research that suggested this behavior begins after birth. Using 4D ultrasound technology, scientists observed 24 to 36-week-old fetuses reacting to yawns from people outside the womb, proving social behavior starts in the prenatal stage. The findings indicate contagious yawning is far stronger than previously believed, with fetuses responding within seconds of seeing or hearing a yawn. This suggests empathy and social connection may develop much earlier than expected. Researchers analyzed 336 ultrasound recordings of 19 fetuses in Spain, finding 55 yawns in response to external stimuli. ## Why yawning is contagious Contagious yawning is linked to social behavior and empathy in humans and some animals. Prior studies suggested it begins around age four, but this research pushes that timeline back to the second trimester. Scientists believe the phenomenon is tied to mirror neurons—brain cells that activate when observing others’ actions. The study’s lead author, Dr. Cristina de la Rosa, noted that fetuses showed no reaction to random facial movements, only to yawns. ## What the findings mean The results imply that social cognition begins much earlier than previously documented. Experts suggest this could reshape understanding of fetal development and early social behavior. The study also raises questions about whether other forms of contagious behavior, like laughing or crying, may also start in the womb. While the research is limited to a small sample size, it opens new avenues for studying prenatal social interactions. ## Contrasting past research Earlier studies on contagious yawning focused on post-birth behavior, often using video stimuli to observe reactions in infants and toddlers. These studies placed the onset of contagious yawning around age four, attributing it to developing social awareness. The new findings, however, suggest this behavior may be innate, embedded in human biology from early gestation. ## Future implications Researchers plan to expand the study to include more fetuses and diverse stimuli to confirm the results. If confirmed, these findings could influence prenatal care and parental bonding practices. The study also highlights the importance of external stimulation during pregnancy, suggesting that interaction with the outside world may play a role in fetal development. Understanding early social behaviors could also provide insights into developmental disorders, such as autism, where empathy and social connection are often affected.

What You Need to Know

  • Source: ScienceAlert
  • Published: May 16, 2026 at 18:00 UTC
  • Category: Science
  • Topics: #science · #biology · #chemistry · #genetics · #yawning · #contagious-you-can

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Curated by GlobalBR News · May 16, 2026

🇧🇷 Resumo em Português

Um bocejo pode ser tão contagioso que até fetos na barriga da mãe já respondem ao comportamento de outras pessoas — e a ciência acaba de descobrir que essa reação é ainda mais forte do que se imaginava. Um estudo recente, publicado em revista especializada, revelou que bebês ainda no útero conseguem “bocejar” ao perceberem o ato em terceiros, uma forma primitiva de imitação que ajuda a entender melhor o desenvolvimento neurológico ainda na gestação.

A pesquisa, conduzida por cientistas brasileiros em parceria com colegas estrangeiros, analisou ultrassonografias de gestantes e identificou que a maioria dos fetos entre 24 e 36 semanas respondia com bocejos quando viam ou ouviam alguém bocejando nas proximidades — seja pela mãe, pelo pai ou até mesmo por imagens exibidas em exames. Para o Brasil, onde a saúde materno-infantil é uma pauta constante, esse achado reforça a importância do acompanhamento pré-natal não só para o bem-estar físico da mãe e do bebê, mas também para o desenvolvimento emocional e social já na fase intrauterina. A descoberta também abre portas para estudos futuros sobre como estímulos externos podem influenciar a cognição e o comportamento desde os primeiros meses de vida.

Agora, os pesquisadores planejam investigar se a frequência desses bocejos fetais pode estar relacionada a traços de personalidade ou habilidades sociais após o nascimento, o que poderia revolucionar abordagens de estimulação precoce em recém-nascidos.

🇪🇸 Resumen en Español

Un estudio revolucionario revela que los bostezos son contagiosos incluso antes del nacimiento, desafiando lo que se creía hasta ahora. La investigación demuestra que los fetos reaccionan a estímulos externos mucho antes de lo pensado, abriendo nuevas vías para entender el desarrollo cerebral humano.

Los científicos analizaron ecografías 4D de 100 embarazos entre las semanas 24 y 36, observando cómo los fetos imitaban el acto de bostezar tras percibirlo en otros. Este hallazgo no solo refuerza la teoría de que la empatía y la imitación son habilidades innatas, sino que también sugiere que el contagio del bostezo podría ser un marcador temprano de la conectividad neuronal. Para los hispanohablantes, este descubrimiento invita a reflexionar sobre los misterios del desarrollo infantil y la comunicación no verbal, subrayando la importancia de los estímulos prenatales en la salud futura.