Newborn babies laugh, just like giggling chimpanzees.
That is according to a new study, which found that – just like their non-human cousins of primates – babies breathe and breathe in while they bark happily.
Adults and older children, on the other hand, generally laugh with an out-breath.
Psychologists made the discovery after studying video's of 44 children between the ages of three months and 18 months.
Newborn babies laugh just like giggling chimpanzees. They inhale and exhale during a couple, while adults and older children tend to breathe out (stock image)
Principal researcher Dr Disa Sauter, of the University of Amsterdam, said: "Adult people sometimes laugh at the inhalation, but the relationship is clearly different from that of the laugh of infants and chimpanzees.
& # 39; Our results so far suggest that this is a gradual, rather than a sudden, shift. & # 39;
The recordings were analyzed by 102 psychology students who assessed the extent to which the babies laughed during exhalation and inhalation.
The findings showed that the youngest babies often laughed during inhalation and exhalation.
But laughter from older babies was mainly produced during exhalation.
The researchers are looking to see if there is a connection with what triggers laughter, which also changes with age.
Like non-human primates, babies & younger babies laugh when they are tickled or engage in other forms of physical play.
One study found that – just like their non-human cousins of primates – babies breathe and breathe in while they are happily kirren (stock image)
As people get older, laughter begins to emerge from social interactions.
Dr. Sauter added: "I would like to see if our findings apply to vocalizations other than laughter.
& # 39; Ultimately, the research can provide insight into the vocal production of children with developmental disorders.
& # 39; If we know how normal developing baby's sound, it may be interesting to study babies who are at risk to see if there are very early signs of atypical development in their non-verbal vocalization of emotions. & # 39;
The findings were presented at the annual meeting of the Acoustical Society of America in Victoria, Canada.
WHO IS SMARTER: CHIMPS OR CHILDREN?
Most children surpass the intelligence levels of chimpanzees before they are four years old.
A study conducted by Australian researchers in June 2017 tested children on foresight, which is said to distinguish humans from animals.
In the experiment, researchers saw a grape drop through the top of a vertical plastic Y-tube.
They then followed the reactions of a child and a chimpanzee to their attempts to grab the grape on the other side before it hit the ground.
Because there were two possible ways in which the grape could leave the pipe, the researchers looked at the strategies the children and chimpanzees used to predict where the grape would go.
The monkeys and the two-year-olds only covered a single hole with their hands when they were tested.
But at the age of four the children had developed to a level where they knew how to predict the outcome.
They covered the holes with both hands and caught what fell through each time.