In a jocular TED-Ed lesson written by Sasha Winkler and animated by Hannah Rybak, narrator Susan Zimmerman explains the science and beneficial biology behind spontaneous laughter, noting how this behavior is not unique to humans.
Importantly, humans are not the only animals today that do something like laughter. … Scientists have since compiled evidence of at least 65 species— mostly mammals, but also some birds— that vocalize during social play. Some, unsurprisingly, are our closest relatives.
The lesson further notes that laughter in humans is instinctive from a young age, operating as a social pathway.
Some scientists …hypothesize that laughter gradually became something we could use not just during play but within speech to convey subtle meanings and a range of contexts to show our emotions. This is thought to be one of the reasons that laughter is contagious:it’s like an invitation to share in someone’s emotional state.
Laughter can also help to improve one’s health.
When we laugh, our brains release feel-good neurotransmitters like endorphins, and decrease levels of stress hormones like cortisol. Some research even suggests that people who laugh more can cope with stress more effectively and have better cardiovascular health.