Shabina Akhtar explains: Laughter is the biological reaction of humans to moments of humour. Depending upon the extent and pitch, laughter can be subcategorised as giggles, chuckles, guffaws etc. Smiling may be considered a mild silent form of laughter.

Prof Malati Ghosh, head of psychiatry department, NRS Medical College and Hospital, Calcutta, says, “Human laughter has its biological origins as a kind of shared expression of relief at the passing of danger. The relaxation we feel after laughing may help inhibit the fight-or-flight response , making laughter a behavioural sign of trust in one’s companions.”

Laughter is a part of human behaviour regulated by the brain. It provides an emotional context to our conversations. It is used as a signal for being part of a group ? it signals acceptance and positive interactions. Humour is a mature form of ego defence mechanism, which enables a person to focus on anxiety provocating issues without suffering from anxiety actually, she added.

We also tend to laugh on being tickled. The reason being that when anyone is tickled then there is an element of surprise followed by feelings like panic, laughter and sensation, which eventually breaks into peals of laughter. But we loose this element of surprise when we try to tickle ourselves. As our brain instantaneously comprehends what is about to happen.

The question was sent by Tuhin Purkayastha from Calcutta.