What is the scientific origin of laughter? (and the enormous amount of animal species emitting similar sounds)

Recent research has discovered that at least 65 species of animals – such as cows, parrots, dogs, dolphins or uracas – emit similar sounds when they play or even when they tickle them, as the apes occur and the apes and the rats.

This suggests that laughter is not something exclusively human, but has very old evolutionary roots, shared with other animals.

In fact, the laughter of the apes when playing could be the evolutionary origin of our laughter. Unlike speech, which requires complex language, laughter is instinctive and contagious, which reinforces the feeling of belonging to the group.

Scientists believe that this social function probably arose with the Homo Ergaster About two million years ago, since it generated group cohesion without language.

But why do certain stimuli find us funny? Gelotology, the science that studies laughter, has been looking for an answer to this question for years. And despite the more than twenty theories that try to explain it, there is no definitive consensus.

However, most current models coincide with three key factors: the perception of a violation of expectations (incongruity), the evaluation of that violation as harmless and the simultaneity of both processes.

That is, laughter appears when something challenges our expectations suddenly but harmless, and we process it immediately.

For example, if someone stumbles with a banana peel and gets up laughing, our brain records the surprise (“how unexpected!”) And, when there is no risk (“it is only a silly fall”), it releases that tension with a loud of relief because there is no real threat.

This mechanism explains why a failed joke does not cause grace (lack of surprise) or why a real accident is not comical (the event is not harmless).

However, not all humorous stimuli are universal.

Cultural, personal and contextual differences deeply affect what is considered funny. The same joke can be comic in a culture, offensive in another or completely irrelevant in a third.

But what happens in our brain since we perceive something funny until we laugh?

Several studies have shown that humor processing involves multiple regions. Thus, while the incongruity is detected in the dorsolateral prefrontal cortex, the temporary -occipital union evaluates its harmless character.

Once this absence of risk has been confirmed, changes in the periacueductal gray substance are produced and the reward circuit is activated (releasing the neurotransmitter dopamine), which finally triggers laughter.

Interestingly, not all laughs are the same. The emotional laugh linked to a state of genuine pleasure is innate and spontaneous, mainly activating brain structures associated with emotional reward, such as the Accumbens nucleus and the tonsil.

On the other hand, voluntary laughter is learned and works as a social tool to imitate or reinforce emotional ties and depends on brain areas responsible for conscious movements.

Thus, each type of laugh reflects different neuronal mechanisms: automatic against the social.

In addition, it has been observed that young people tend to show greater activation in areas linked to emotional pleasure, which reflects a more intense and primary experience of humor.

On the other hand, more those areas related to complex processing, associative reflection and autobiographical memory are lit in adults.

This would explain how due to accumulated experience, adults contextualize humor through memory and prefer complex styles (such as sarcasm), while young people, with less vital experiences, seek immediate stimuli (such as physical or absurd humor).

Beyond its emotional and social dimension, laughter also has a powerful therapeutic effect.

When we laugh, the endogenous opioid system – related to sensations of pleasure and calm – is activated, promoting the release of neurotransmitters such as dopamine and serotonin, key substances in psychological well -being and in the reduction of stress.

Several studies support the efficacy of laughter to improve the quality of life, especially in the elderly, where the frequency of laughter is associated with lower risk of functional disability.

The so -called risotherapy helps reduce cortisol levels (stress hormone), relieve depression and anxiety, improve sleep quality and even increase pain tolerance.

The positive effects of laughter also extend to the hospital scope: in children and adolescents subject to medical procedures, the presence of clowns has shown significantly reduce anxiety, pain and stress.

In short, laughter is not just a pleasant hobby or an occasional luxury. It is a fundamental pillar in our health and social welfare. Learning to laugh more, looking for reasons for joy in everyday life, can be as crucial for our life as taking care of food or physical exercise.

Laughter has the ability to transform our biology, our mind and our relationships. Perhaps the humorist Victor Borge (1909-2000) was right when he said it is the shortest distance between two people.

*This article was published in The Conversation and reproduced here under the Creative Commons license. Click here To see the original version.

** Marta Calderón García is a researcher in cognition, behavior and neurocriminology at Miguel Hernández University in Spain.

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