Laughter as an Evolutionary Adaptation

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Laughter is a social behavior which typically signifies a shared joy among individuals. It is an evolutionary adaptation common among many social primate species and it is believed to be associated with social bonding among individuals, similar to grooming behavior.

Laughter is characterized by its rhythmic structure as bursts of sounds occurring at regular intervals.

Unlike other primate species who tend to produce laughter on both the inhale and exhale of a breath, humans produce laughter solely through the interruption of a single exhale (i.e. ha-ha-ha).

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This distinct characteristic of human laughter is thought to be a more recent evolutionary development as it relates to the way we produce sounds when we communicate (i.e. we communicate by modifying an exhale). With chimpanzees and other primates producing laughter on both the inhale and exhale, laughter for them is more closely associated with exerted breathing (i.e. panting).

As such, evolutionary researchers believe that laughter may have evolved in primates through play behavior. Primates play by chasing one another, a behavior that tends to lead to exertion and heavy breathing (again - panting). This type of breathing may be accentuated by the individual in order to convey joy to the other and signify that they are having fun.

Humans on the other hand, tend to laugh as a form of communication.

Social Brain Hypothesis

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According to the social brain hypothesis of laughter the human brain is believed to have grown rapidly along with population increase. As the group became larger, it naturally became more complex socially. This social complexity can be quite challenging at times for the individual especially in terms of bonding with larger groups. As such, communication developed in humans as a way of bonding with larger groups in short amounts of time. For instance, grooming behavior and one on one play which lead to social bonding in many primate species, takes a lot of time and becomes increasingly harder to do as group size increases. Communication solves this evolutionary problem.

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Laughter is an extension of communication. In large groups, laughter signals to others that they are a part of the group – that they are involved and/or participating in what is going on.

The interesting and somewhat confusing thing about laughter is that the mechanism to be able to laugh is an innate quality that we are born with rather than a learned behavior. It is actually built into our genetic code to be able to laugh which makes it even more challenging to understand. However, one explanation for this is that laughter acts as a release mechanism.

During conversation there tends to be a buildup of energy in the brain for the individual. This cortical excitation, that tends to take place in the part of the brain responsible for vocalization, needs to be relieved in some way. As such, if the individual does not have anything to say or a means to say it, the stored energy is released in the form of laughter.

Fun fact about @leaky20

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I have been told on many occasions by many different people that my laugh is more like a cackle ahh-ha-ha-ha. I think that this really fits my whole bird persona. lol

Thanks For Reading

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References:

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Marijuan, P. C. & Navarro, J. (2010). The bonds of laughter: a multidisciplinary inquiry into the information processes of human laughter. Quantitative Biology - Neurons and Cognition.

Van de Braak, H. (2013). Evolutionary Psychology. Harlow, Essex: Pearson