Why we are Laughing every time , We are Happy are not ?

How do our brains know when something is funny? As science reporter Tanya Lewis explains, it's thanks to the frontal lobe of our brain, which is responsible for our emotional responses. So while the left side is responsible for interpreting the words and structure of a joke, the right side determines whether that joke is funny or not.

Research has also shown that the limbic system at the centre of the brain - which contains the amygdala and hippocampus and processes our most basic emotions, such as hunger and fear - is also triggered when we see or hear something funny. This activity eventually stimulates the motor region of the brain to become active, and that's what produces the physical reaction of laughing and the vocal expulsion of sound.

On average, humans have this laughter reaction around 17 times a day, and as far as we know, we're one of the only species on the planet that laughs. Some primates do show signs of laughter when they're tickled, but scientists aren't quite sure if this is the same as human laughter.

The best part about all of this is that laughter is actually good for you. As the video above explains, researchers at the University of Maryland in the US have linked laughter to the healthy function of blood vessels - something that can lower your chance of a heart attack. And laughter also boosts heart rate and the production of certain antibodies, which strengthens our immune system.