Laughter is of two types - genuine and artificial- states a new study published in the current Quarterly Review of Biology.

The study, which explains how laughter has evolved over the past seven million years, found that the first type is spontaneous and stimulus-driven, while the second, is strategic and, at times, downright cruel, also nicknamed “the dark side of laughter “.

One type of laughter arises spontaneously from the perception of a certain class of events, while the other is used strategically in interaction to influence others or modulate one’s own physiology.

The researchers said that people who spontaneously laugh more are genetically superior to those who hardly ever chuckle. They could be healthier, happier, more attractive or more cooperative.