There's nothing quite like that yelp of laughter you emit when being tickled.
Now, experts have confirmed that shrieks induced by tickling really do sound recognisably different to other types of giggles.
During a listening experiment, around 200 people tasked with identifying types of laughter.
This included tickling-induced giggles, laughter at a joke, chuckles at seeing something funny, and the guffaw at a humorous mishap.
The results revealed that people were able to identify tickling-induced laughter with around 60 per cent accuracy.
A second listening experiment and AI analysis of 887 YouTube clips revealed ticklish laughter exhibits less vocal control than other types.
Participants also rated ticklish laughter as being more involuntary.
The researchers, from the University of Amsterdam, said their findings highlight tickling as an evolutionary ancient play behaviour.
There's nothing quite like that yelp of laughter you emit when being tickled. Now, experts have confirmed that shrieks induced by tickling really do sound recognisably different to other types of giggles (stock image)
During a listening experiment, around 200 people tasked with identifying types of laughter (stock image)
Writing in the journal Biology Letters the team said: 'Laughter has deep evolutionary roots: many mammals, including chimpanzees, squirrel monkeys and dogs produce laughter-like vocalizations during play.
'In humans, laughing is one of the first complex social behaviours we engage in: human infants start to laugh within weeks of birth.
'Laughing is ubiquitous in human life, yet what causes it and how it sounds is highly variable.
'In a listening experiment, participants could accurately identify tickling-induced laughter, validating that such laughter is not only acoustically but also perceptually distinct.'
They said the heightened arousal observed in tickling-induced laughter, with its reduced vocal control, suggests it is an 'automatic response' to the act of being tickled.
Previous research indicates that laughing when tickled in our sensitive spots – under the arms, near the throat and under our feet – could be a defensive mechanism.
Evolutionary biologists and neuroscientists believe that we giggle when being tickled because the part of the brain that tells us to laugh when we experience a light touch, the hypothalamus, is also the same part that tells us to expect a painful sensation.
Studies suggest that we have evolved to laugh to show our submission to an aggressor, to dispel a tense situation and prevent us from getting hurt.
CAN LAUGHING AT YOURSELF IMPROVE YOUR MENTAL HEALTH?
A new study from researchers in Spain has found that laughing at oneself might be good for you. (file photo)
Researchers in Spain have discovered that laughing at oneself is not necessarily a bad thing.
A new study revealed that self-defeating humor might have an effect on how angry you are.
But the report explained how some people use humor to cover up negative thoughts.
The study said: 'The researchers are quick to point out that certain styles of humor may be employed to conceal negative intentions and feelings.'
One of the researchers explained the potential dark sides of the tactic, saying that the 'results suggest that humor, even when presented as benign or well-intentioned, can also represent a strategy for masking negative intentions.
'Humor enables individuals with low scores in honesty to build trust, closeness, etc. with other people and thereby use important information in order to manipulate them or obtain advantages in the future.'
