A recent study revealed that the laughing style of babies is the same as that of a chimpanzee. Professor Mariska Kret from Leiden University in the Netherlands explained that adults laugh while breathing out, whereas Chimpanzees and babies laugh while breathing in and out.

Several scholars have tried to explain how these similarities could occur.

However, Marina Darita Ross, a study leader, adds that the trait does not occur with the entire ape family but with the genetically closest species to humans, like the chimpanzees and bonobos.

Adults tend to inhale and produce sounds in fast fading bursts when they laugh. However, many researchers found the laughter in apes more challenging to describe.

How researchers conducted the study

To support her study, Kret compiled audio clips of children aged eighteen months to three years laughing and requested that her audience evaluate the rate at which they laughed.

For their control, the researchers added five clips of grown-ups laughing and presented them to an audience. Listeners agreed on the different patterns of laughter between adults compared with babies and chimpanzees. Researchers then employed the expertise of sound listeners who confirmed their findings.

Furthermore, researchers found that as the baby grew older, their airflow changed. For this reason, Davilla-Ross implored us to be open to the idea of finding other forms of vocalization in humans that come to the same conclusion.  In the meantime, Kret is currently working on a study with apes to determine if external factors can influence their laughter.

Laughing patterns in adults

The researchers also carried out a similar experiment and asked the audience to rate the laughter from the most to the least contagious. A recent publication by the Biology letters highlighted that people perceived the laughter produced from breathing out as positive.

The publication indicated that the laughter seemed to be louder and more controlled. Kret, who supported this theory, also recognized that this makes it easier for infants to communicate that they would like to continue playing.

According to the study, older babies produced an exhaling rate of laughter than the younger ones as they learned to use laughter as a communicative tool once they grew older.